{
    "name": "Sleep Align Night-Time Symptom Reference",
    "description": "Fifty night-time symptoms mapped to the sleeping position associated with them, the likely mechanical cause, the conservative change described by mainstream sources, the condition each is commonly confused with, and the sign that means see a clinician. Every row cites a published source. Rows with no established position link say so.",
    "url": "https://sleepalign.org/night-symptom-reference/",
    "license": "https://creativecommons.org/licenses/by/4.0/",
    "attribution": "Sleep Align (sleepalign.org), CC BY 4.0",
    "version": "2026-08-29",
    "row_count": 50,
    "rows": [
        {
            "id": "arm-numb-night",
            "region": "Arm & hand",
            "symptom": "Arm goes numb during the night",
            "timing": "During the night",
            "position": "Lying on the arm, or with it trapped under the body, head or a partner",
            "mechanism": "Sustained body weight on a nerve cuts its blood supply and blocks signalling. The classic sleep case is radial nerve compression at the mid upper arm.",
            "change": "Change position so nothing rests on the arm - keep it out from under the head, body or partner.",
            "not_this": "Cervical nerve root compression, or systemic neuropathy from diabetes or B12 deficiency.",
            "red_flag": "Numbness that persists after moving, or a wrist that cannot lift itself (wrist drop).",
            "source_name": "StatPearls, NCBI Bookshelf",
            "source_url": "https://www.ncbi.nlm.nih.gov/books/NBK532993/",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "hand-numb-which-fingers",
            "region": "Arm & hand",
            "symptom": "Which fingers go numb tells you which nerve",
            "timing": "Any time in bed",
            "position": "not established",
            "mechanism": "Each nerve supplies fixed digits: median serves thumb, index, middle and the radial half of the ring finger; ulnar serves the little finger and ulnar half of the ring; radial the back of the thumb web.",
            "change": "no positional change described",
            "not_this": "Numbness across the whole hand or both hands suggests systemic neuropathy, not local compression.",
            "red_flag": "Numbness that does not match one nerve map, or comes with weakness, confusion, slurred speech or facial droop.",
            "source_name": "StatPearls, NCBI Bookshelf",
            "source_url": "https://www.ncbi.nlm.nih.gov/books/NBK544247/",
            "source_2_url": "",
            "source_note": "Nerve distribution map, not a positional complaint - no position link claimed."
        },
        {
            "id": "hands-tingling-night",
            "region": "Arm & hand",
            "symptom": "Hands tingling at night",
            "timing": "During the night",
            "position": "Wrists flexed or curled in sleep; side sleeping was linked to fewer night symptoms",
            "mechanism": "Curling the wrists in sleep narrows the carpal tunnel and squeezes the median nerve. A survey of healthy adults found 33% reported weekly night tingling.",
            "change": "Sleep with the wrists straight. The same survey linked flexed wrists to more symptoms and side sleeping to fewer.",
            "not_this": "Peripheral neuropathy from diabetes, thyroid disease or B12 deficiency rather than positional pressure.",
            "red_flag": "Numbness that is constant rather than intermittent, hand weakness, or wasting at the base of the thumb.",
            "source_name": "HAND (SAGE)",
            "source_url": "https://journals.sagepub.com/doi/10.1177/1558944717735942",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "pinky-ring-numb",
            "region": "Arm & hand",
            "symptom": "Little and ring finger numb at night",
            "timing": "During the night",
            "position": "Elbow bent, often with the hand tucked under the head or pillow",
            "mechanism": "A bent elbow stretches and compresses the ulnar nerve behind the inner elbow and reduces its blood supply, so the ring and little fingers go numb.",
            "change": "Keep the elbow straight at night - for example a towel wrapped round the straight elbow, or an elbow pad worn backwards.",
            "not_this": "Compression higher up at the neck or thoracic outlet, or a generalised neuropathy.",
            "red_flag": "Muscle wasting in the hand, weakness, or symptoms lasting more than six weeks.",
            "source_name": "AAOS OrthoInfo",
            "source_url": "https://www.orthoinfo.org/diseases--conditions/ulnar-nerve-entrapment-at-the-elbow",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "thumb-index-numb",
            "region": "Arm & hand",
            "symptom": "Thumb, index and middle finger numb at night",
            "timing": "During the night",
            "position": "Wrist bent, hand curled under the pillow or body",
            "mechanism": "Bending or extending the wrist raises carpal tunnel pressure from a normal 2-10 mmHg to eight to ten times that level, compressing the median nerve.",
            "change": "Keep the wrist in a straight, neutral position at night instead of letting it curl.",
            "not_this": "Cervical radiculopathy at the neck, or diabetic polyneuropathy producing a similar finger pattern.",
            "red_flag": "Constant rather than intermittent numbness, or visible wasting of the thumb base muscles.",
            "source_name": "StatPearls, NCBI Bookshelf",
            "source_url": "https://www.ncbi.nlm.nih.gov/books/NBK448179/",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "arm-falls-asleep",
            "region": "Arm & hand",
            "symptom": "Arm falls asleep and wakes you",
            "timing": "During the night",
            "position": "Limb trapped under the body, head or a partner",
            "mechanism": "Prolonged pressure on a nerve restricts signalling and blood flow like a kink folded into a hose, so sensation drops until the position changes.",
            "change": "Shift position and free the limb. Sensation normally returns once pressure comes off the nerve.",
            "not_this": "Persistent paresthesia from diabetes, B12 deficiency, thyroid disorder or multiple sclerosis rather than pressure.",
            "red_flag": "Tingling on both sides at once with weakness or loss of balance, or sudden one-sided weakness.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/symptoms/24932-paresthesia",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "hands-swollen-morning",
            "region": "Arm & hand",
            "symptom": "Hands swollen or puffy in the morning",
            "timing": "On waking",
            "position": "not established",
            "mechanism": "Hand volume rises overnight in healthy adults by an average of 4.3%, about 20.9 mL, attributed to reduced movement and circadian fluid shift rather than posture.",
            "change": "no positional change described",
            "not_this": "Inflammatory arthritis, or heart, kidney, liver or thyroid disease causing true fluid retention.",
            "red_flag": "Swelling in one limb only, sudden or painful swelling, or swelling with breathlessness or chest pain.",
            "source_name": "American Society for Surgery of the Hand",
            "source_url": "https://meeting.handsurgery.org/files/2018/ePosters/HSEP43.pdf",
            "source_2_url": "",
            "source_note": "Conference ePoster, 36 healthy volunteers. Peer-reviewed version exists but full text was not retrievable."
        },
        {
            "id": "fingers-stiff-waking",
            "region": "Arm & hand",
            "symptom": "Fingers stiff on waking",
            "timing": "On waking",
            "position": "not established",
            "mechanism": "Joints stiffen after hours without movement. An inflamed joint lining prolongs that stiffness and leaves the small hand joints swollen, hot and tender.",
            "change": "no positional change described",
            "not_this": "Rheumatoid arthritis or osteoarthritis rather than anything about the bed, pillow or position.",
            "red_flag": "Morning stiffness lasting longer than 30 minutes, or fingers that cannot fully close into a fist.",
            "source_name": "NHS",
            "source_url": "https://www.nhs.uk/conditions/rheumatoid-arthritis/symptoms/",
            "source_2_url": "",
            "source_note": "Sources tie this to arthritis, not to bed setup. No position link claimed."
        },
        {
            "id": "arms-above-head",
            "region": "Arm & hand",
            "symptom": "Numbness when sleeping with arms above the head",
            "timing": "During the night",
            "position": "Habitual shoulder hyperabduction, arm raised overhead through the night",
            "mechanism": "Raising the arm narrows the thoracic outlet and compresses the lower brachial plexus and subclavian vessels, numbing the inner arm and ulnar-side fingers.",
            "change": "Correct the habitual overhead sleeping posture - the authors note this everyday habit change is achievable and preventive.",
            "not_this": "Ulnar compression at the elbow, or median compression at the wrist, lower down the arm.",
            "red_flag": "Wasting of the hand muscles, weak grip, or arm swelling and discoloration.",
            "source_name": "Annals of Rehabilitation Medicine",
            "source_url": "https://www.e-arm.org/journal/view.php?number=36",
            "source_2_url": "",
            "source_note": "Single case report plus general thoracic outlet material. Position link is real but thinly evidenced."
        },
        {
            "id": "elbow-bent-tingling",
            "region": "Arm & hand",
            "symptom": "Elbow tingling when the arm is bent at night",
            "timing": "During the night",
            "position": "Elbow held bent for long stretches in bed",
            "mechanism": "Bending the elbow stretches the ulnar nerve over the bony inner elbow and reduces its blood supply, producing tingling toward the ring and little fingers.",
            "change": "Sleep with the elbow straight, and avoid holding the arm bent for long periods.",
            "not_this": "Neck nerve root compression or generalised neuropathy rather than local elbow pressure.",
            "red_flag": "Symptoms that are severe, last more than six weeks, or come with hand muscle wasting.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/diseases/21997-cubital-tunnel-syndrome",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "outer-thigh-numb",
            "region": "Leg & hip",
            "symptom": "Outer thigh numbness or burning at night",
            "timing": "Any time in bed",
            "position": "Hip extension with the leg straight; hip flexion such as sitting relieves it",
            "mechanism": "The lateral femoral cutaneous nerve is compressed under the inguinal ligament at the groin. Prolonged hip extension and tight waistbands increase that pressure.",
            "change": "Loosen or remove tight belts and waistbands. Sources describe hip flexion easing symptoms and prolonged extension aggravating them.",
            "not_this": "Lumbar radiculopathy, which usually includes back pain and is not confined to the outer thigh.",
            "red_flag": "Leg weakness, or accompanying back pain - this nerve problem is purely sensory.",
            "source_name": "StatPearls, NCBI Bookshelf",
            "source_url": "https://www.ncbi.nlm.nih.gov/books/NBK557735/",
            "source_2_url": "",
            "source_note": "The hip-extension link describes daytime posture; no source ties this to a sleeping position."
        },
        {
            "id": "leg-numb-side-sleeping",
            "region": "Leg & hip",
            "symptom": "Leg goes numb when sleeping on your side",
            "timing": "During the night",
            "position": "Side lying with body weight on the lower leg, or legs crossed",
            "mechanism": "Sustained pressure from body weight or crossed legs interrupts nerve signalling. The common peroneal nerve at the fibular head is especially exposed.",
            "change": "Change position to release the pressure. Feeling should return once the limb is extended.",
            "not_this": "Peripheral neuropathy or diabetes-related nerve damage, which is persistent rather than position-triggered.",
            "red_flag": "Numbness affecting both sides equally, or weakness, foot drop or loss of balance.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/symptoms/24932-paresthesia",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "foot-numb-night",
            "region": "Leg & hip",
            "symptom": "Foot numbness at night",
            "timing": "During the night",
            "position": "Not established for sleep; symptoms are linked to extremes of ankle dorsiflexion and eversion, and to walking or standing",
            "mechanism": "The tibial nerve is compressed inside the tarsal tunnel on the inner ankle. Symptoms may worsen at night and typically improve with rest.",
            "change": "no positional change described",
            "not_this": "Peripheral neuropathy, commonly diabetes-related, which is often worse at night.",
            "red_flag": "Toe weakness, muscle wasting, claw-toe deformity, or a foot sore that will not heal.",
            "source_name": "StatPearls, NCBI Bookshelf",
            "source_url": "https://www.ncbi.nlm.nih.gov/books/NBK513273/",
            "source_2_url": "",
            "source_note": "Source notes night worsening but describes no bedtime position or positional change."
        },
        {
            "id": "calf-cramps-night",
            "region": "Leg & hip",
            "symptom": "Calf cramps at night",
            "timing": "During the night",
            "position": "Foot passively held in plantar flexion during sleep, leaving calf fibres already shortened",
            "mechanism": "The foot sits passively in plantar flexion during sleep with the calf fibres maximally shortened, so uninhibited nerve stimulation leads to cramping.",
            "change": "Loosen the sheets and covers at the foot of the bed.",
            "not_this": "Restless legs syndrome, which is an urge to move, usually not painful, and lasts longer.",
            "red_flag": "Severe continuing cramping, or muscle weakness accompanying the cramps.",
            "source_name": "American Family Physician",
            "source_url": "https://www.aafp.org/pubs/afp/issues/2012/0815/p350.html",
            "source_2_url": "https://www.mayoclinic.org/diseases-conditions/night-leg-cramps/expert-answers/faq-20058069",
            "source_note": "Mechanism from AAFP; the bedding change is Mayo Clinic."
        },
        {
            "id": "toe-cramps-night",
            "region": "Leg & hip",
            "symptom": "Toe cramps at night",
            "timing": "During the night",
            "position": "Not established for toes specifically; the passive plantar flexion described for night calf cramps is the nearest documented posture",
            "mechanism": "Involuntary muscle spasm in the foot. Contributors listed include dehydration, tight or ill-fitting shoes restricting circulation, muscle strain and low electrolytes.",
            "change": "Loosen sheets and covers at the foot of the bed. Tight shoes are a documented daytime trigger for foot cramps.",
            "not_this": "Peripheral neuropathy, which causes numbness, tingling or electrical pain rather than a tightening muscle.",
            "red_flag": "Cramps that are frequent or severe, or occur with muscle weakness.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://health.clevelandclinic.org/dont-let-foot-cramps-charley-horses-slow",
            "source_2_url": "",
            "source_note": "No source describes a toe-specific night position; mechanism is borrowed from the calf-cramp literature."
        },
        {
            "id": "restless-legs",
            "region": "Leg & hip",
            "symptom": "Legs restless with an urge to move at night",
            "timing": "Falling asleep",
            "position": "not established",
            "mechanism": "Not mechanical. An urge to move triggered by inactivity and by attempting to sleep, temporarily relieved by leg movement or walking.",
            "change": "no positional change described",
            "not_this": "Night leg cramps, which are painful and brief. In children it is sometimes misread as growing pains or ADHD.",
            "red_flag": "Symptoms disrupting sleep or daily function. Low brain iron may be responsible.",
            "source_name": "NINDS",
            "source_url": "https://www.ninds.nih.gov/health-information/disorders/restless-legs-syndrome",
            "source_2_url": "",
            "source_note": "Not positional at all - tied to rest and inactivity generally."
        },
        {
            "id": "hip-pain-side-sleeping",
            "region": "Leg & hip",
            "symptom": "Hip pain when sleeping on your side",
            "timing": "During the night",
            "position": "Lying on the affected hip - pain is usually worse at night and when lying on that hip",
            "mechanism": "The bursa covering the greater trochanter becomes inflamed and a tight iliotibial band can press on it, with body weight adding load in side lying.",
            "change": "Side sleepers lie on the hip that is not painful, with one or more pillows between the legs.",
            "not_this": "Referred pain from spine disease, or inflammatory arthritis such as rheumatoid arthritis.",
            "red_flag": "Hip pain not improving after a week or two of rest, or blocking daily activities.",
            "source_name": "AAOS OrthoInfo",
            "source_url": "https://www.orthoinfo.org/diseases--conditions/hip-bursitis",
            "source_2_url": "https://www.arthritis.org/health-wellness/healthy-living/managing-pain/pain-relief-solutions/sleep-positions-joint-pain",
            "source_note": "Mechanism from AAOS; the pillow-between-legs change is Arthritis Foundation."
        },
        {
            "id": "si-joint-pain-night",
            "region": "Leg & hip",
            "symptom": "Sacroiliac joint pain at night",
            "timing": "During the night",
            "position": "Sleeping on the side with the pain",
            "mechanism": "Inflammation of the sacroiliac joint where the lower spine meets the pelvis. Loading it by lying on the painful side or holding one position aggravates it.",
            "change": "Avoid sleeping on the painful side; a pillow under the knees when lying on the back.",
            "not_this": "Ankylosing spondylitis, an inflammatory arthritis for which sacroiliitis is often an early symptom.",
            "red_flag": "Morning stiffness lasting longer than an hour, or new or worsening low back pain.",
            "source_name": "Mayo Clinic",
            "source_url": "https://www.mayoclinic.org/diseases-conditions/sacroiliitis/symptoms-causes/syc-20350747",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "tailbone-pain-lying",
            "region": "Leg & hip",
            "symptom": "Tailbone pain when lying down",
            "timing": "Any time in bed",
            "position": "Lying on your back loads the coccyx; lying on your side reduces pressure on it",
            "mechanism": "Direct pressure and strain on the coccyx. Excess weight can make the tailbone lean backwards, and low body fat reduces its cushioning.",
            "change": "Lie on your side to reduce pressure on the coccyx.",
            "not_this": "Rarely, infection or cancer such as chordoma, prostate or colorectal cancer.",
            "red_flag": "A high temperature with tailbone pain, or pain in another area at the same time.",
            "source_name": "NHS",
            "source_url": "https://www.nhs.uk/conditions/tailbone-coccyx-pain/",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "knee-pain-side-sleeping",
            "region": "Leg & hip",
            "symptom": "Knee pain at night when side sleeping",
            "timing": "During the night",
            "position": "Side lying with the knees pressing together",
            "mechanism": "Joints lubricate less when you are not moving, and in side lying the knees press against one another, adding direct pressure.",
            "change": "Side sleeping with a small pillow between the knees, or back sleeping with a pillow under them.",
            "not_this": "Inflammatory arthritis such as rheumatoid arthritis, or gout, rather than positional pressure.",
            "red_flag": "Knee pain that keeps you awake - healthy knees usually do not hurt at night.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://health.clevelandclinic.org/why-do-i-have-knee-pain-at-night",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "jaw-sore-morning",
            "region": "Head & face",
            "symptom": "Jaw sore or aching in the morning",
            "timing": "On waking",
            "position": "Stomach sleeping, or a hand propped under the head pushing the jaw sideways",
            "mechanism": "The head cannot rest in line with the cervical spine, and a supporting hand puts tension on the jaw and pushes it toward the opposite side.",
            "change": "Avoid stomach sleeping and keep hands out from under the head, so the head rests in line with the cervical spine.",
            "not_this": "Night-time teeth grinding, bite misalignment, or a damaged or infected tooth that hurts more lying down.",
            "red_flag": "Jaw pain with chest discomfort, or pain worsening on exertion - possible heart problem, emergency care.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://health.clevelandclinic.org/waking-up-with-a-sore-jaw-you-may-grind-your-teeth-at-night",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "teeth-grinding-jaw",
            "region": "Head & face",
            "symptom": "Teeth grinding at night with a sore jaw",
            "timing": "During the night",
            "position": "not established",
            "mechanism": "Repetitive clenching and grinding during sleep leaves the jaw muscles tired, tight or sore, and can produce a dull headache starting at the temples.",
            "change": "no positional change described",
            "not_this": "Sleep-disordered breathing - people who grind more often have snoring and breathing pauses during sleep.",
            "red_flag": "Loud snoring or witnessed breathing pauses alongside grinding, or a jaw that locks and will not fully open or close.",
            "source_name": "Mayo Clinic",
            "source_url": "https://www.mayoclinic.org/diseases-conditions/bruxism/symptoms-causes/syc-20356095",
            "source_2_url": "",
            "source_note": "No sleep-position or pillow factor described by the source."
        },
        {
            "id": "ear-pain-side-sleeping",
            "region": "Head & face",
            "symptom": "Ear hurts from sleeping on that side",
            "timing": "During the night",
            "position": "Side sleeping with the ear compressed against the pillow, reported more often on the right ear",
            "mechanism": "Sustained pressure on the ear's thin skin and cartilage behaves like a pressure sore. In one case symptoms began after switching to a firmer pillow.",
            "change": "Sleep on the opposite side, pad the ear with sponge or foam, or use a donut-style pillow with a central hole.",
            "not_this": "A skin cancer such as basal or squamous cell carcinoma, or actinic keratosis, which can look similar.",
            "red_flag": "A lump that grows, bleeds, crusts or persists once pressure is relieved - biopsy may be needed.",
            "source_name": "Cleveland Clinic Journal of Medicine",
            "source_url": "https://www.ccjm.org/content/90/5/277",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "headache-on-waking",
            "region": "Head & face",
            "symptom": "Headache present on waking",
            "timing": "On waking",
            "position": "not established",
            "mechanism": "Sources tie this to sleep itself rather than head posture - insomnia, breathing pauses, teeth-grinding tension across the face and head, oversleeping, or alcohol.",
            "change": "no positional change described",
            "not_this": "Obstructive sleep apnea - more than half of people with sleep apnea have headaches.",
            "red_flag": "Waking headaches three or more times a week, or loud snoring with breathing pauses during sleep.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://health.clevelandclinic.org/waking-up-with-a-headache",
            "source_2_url": "",
            "source_note": "No pillow or position factor described. This is a breathing-disorder route, not a pillow problem."
        },
        {
            "id": "face-numb-side-sleeping",
            "region": "Head & face",
            "symptom": "Face or cheek numb after sleeping on one side",
            "timing": "On waking",
            "position": "Any position holding steady pressure on one side of the face or head for a long stretch",
            "mechanism": "The position presses on a nerve or limits blood flow to it, like folding a kink into a hose. Feeling returns after the pressure is released.",
            "change": "Shift position to take pressure off the area - transient pressure numbness resolves once the position changes.",
            "not_this": "A nerve or central cause such as stroke, rather than simple positional pressure.",
            "red_flag": "Numbness with weakness, loss of function, loss of balance or facial droop - treat as possible stroke, emergency.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/symptoms/24932-paresthesia",
            "source_2_url": "",
            "source_note": "Source describes positional pressure numbness generically, not the cheek specifically."
        },
        {
            "id": "sleep-lines-face",
            "region": "Head & face",
            "symptom": "Sleep lines and creases on the face from the pillow",
            "timing": "On waking",
            "position": "Side and stomach sleeping",
            "mechanism": "Compression, tension and shear forces against the pillow distort the skin, forming lines that run perpendicular to expression lines on the forehead, lips and cheeks.",
            "change": "Sleep on the back, or use a pillow designed to minimise facial contact with the sleep surface.",
            "not_this": "Expression wrinkles from repeated facial muscle movement, which differ in cause, location and anatomical pattern.",
            "red_flag": "None described by the source. A new or changing mole or lesion, rather than a fading crease, warrants a dermatologist.",
            "source_name": "Aesthetic Surgery Journal",
            "source_url": "https://academic.oup.com/asj/article/36/8/931/2613967",
            "source_2_url": "",
            "source_note": "The source describes no red flag; the referral line is a conservative addition, not a sourced claim. A '65% of sleep time in the lateral position' figure was dropped - it sits behind the paywall and could not be verified."
        },
        {
            "id": "drooling-side-sleeping",
            "region": "Head & face",
            "symptom": "Drooling when sleeping on your side",
            "timing": "During the night",
            "position": "Side or stomach sleeping",
            "mechanism": "Sleeping on the back lets gravity keep saliva in the mouth, while side or stomach sleeping lets gravity pull it out instead.",
            "change": "Sleeping on the back keeps saliva in the mouth.",
            "not_this": "Mouth breathing from nasal congestion, allergies, swollen adenoids or sinusitis, or reflux.",
            "red_flag": "Excessive or sudden drooling, or trouble swallowing - can signal a neurological condition such as stroke or Parkinson's.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/symptoms/22384-drooling",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "dry-mouth-waking",
            "region": "Head & face",
            "symptom": "Dry mouth on waking",
            "timing": "On waking",
            "position": "not established",
            "mechanism": "Snoring and breathing with the mouth open during sleep can lead to dry mouth.",
            "change": "no positional change described",
            "not_this": "Medicines - hundreds of drugs reduce saliva - plus Sjogren syndrome, radiation to head or neck, and tobacco.",
            "red_flag": "Dry mouth that does not go away needs review. Snoring or breathing pauses point to a breathing-disorder assessment.",
            "source_name": "Mayo Clinic",
            "source_url": "https://www.mayoclinic.org/diseases-conditions/dry-mouth/symptoms-causes/syc-20356048",
            "source_2_url": "https://my.clevelandclinic.org/health/diseases/22734-mouth-breathing",
            "source_note": "The snoring clause of the red flag comes from the Cleveland Clinic mouth-breathing page."
        },
        {
            "id": "one-nostril-blocks",
            "region": "Head & face",
            "symptom": "One nostril blocks when you lie on that side",
            "timing": "Any time in bed",
            "position": "Lying on one side - the lower dependent nostril congests while the upper nostril opens",
            "mechanism": "A corporo-nasal reflex plus hydrostatic engorgement. Lying down raises central venous pressure by up to 8 mmHg, swelling the nasal lining independent of sympathetic control.",
            "change": "Turning onto the other side changes which nostril is open; the spontaneous cycle resumes if one position is held.",
            "not_this": "The normal nasal cycle, present in 70-80% of adults, with phases lasting 30 minutes to 6 hours.",
            "red_flag": "Blockage always on the same side regardless of position, or with bleeding or facial pain - ENT review.",
            "source_name": "Rhinology Online",
            "source_url": "https://www.rhinologyonline.org/Rhinology_online_issues/manuscript_16.pdf",
            "source_2_url": "",
            "source_note": "Review article; the primary posture-and-patency study was behind a CAPTCHA and not retrieved."
        },
        {
            "id": "eyes-puffy-morning",
            "region": "Head & face",
            "symptom": "Eyes puffy in the morning",
            "timing": "On waking",
            "position": "Lying flat, which lets fluid collect in the tissue around the eyes and eyelids overnight",
            "mechanism": "Fluid builds up around the eyes and eyelids while lying flat. Retention is most noticeable on waking, or after a salty meal.",
            "change": "Raise the head slightly by adding another pillow, to help prevent fluid building up around the eyes during sleep.",
            "not_this": "Allergy or infection such as conjunctivitis, or thyroid or kidney disease.",
            "red_flag": "Swelling lasting longer than 24-48 hours, or with vision problems, pain or rash - see an eye professional.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://health.clevelandclinic.org/how-to-get-rid-of-eye-bags",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "locked-neck-waking",
            "region": "Neck, back & chest",
            "symptom": "Woke with a locked neck that will not turn",
            "timing": "On waking",
            "position": "Front sleeping, or the neck twisted and held in an awkward position",
            "mechanism": "The neck is held twisted or unsupported for hours, so muscles and joints stiffen and guard, sharply limiting rotation on waking.",
            "change": "A low firm pillow keeping the head level with the body, a firm mattress, and no front sleeping or neck twisting.",
            "not_this": "Meningitis, where a stiff neck comes with fever, severe headache and eye pain in bright light.",
            "red_flag": "Stiff neck with fever, worsening severe headache, eye pain in bright light, confusion or a non-fading rash.",
            "source_name": "NHS",
            "source_url": "https://www.nhs.uk/conditions/neck-pain-and-stiff-neck/",
            "source_2_url": "https://www.nhs.uk/conditions/meningitis/symptoms/",
            "source_note": "Position and pillow advice from the NHS neck page; the meningitis red flag from the NHS meningitis page."
        },
        {
            "id": "neck-pain-one-side",
            "region": "Neck, back & chest",
            "symptom": "Neck pain on one side only after sleeping",
            "timing": "On waking",
            "position": "Front sleeping, or the head turned to one side on a pillow of the wrong height",
            "mechanism": "One side's neck muscles and joints are held shortened or stretched for hours by a turned head, or by a pillow that is too high.",
            "change": "A low firm pillow with the head level with the rest of the body, a firm mattress, no front sleeping, no twisting.",
            "not_this": "A pinched nerve in the neck, which sends pain and pins and needles down the arm.",
            "red_flag": "Pins and needles down the arm, or a cold arm.",
            "source_name": "NHS",
            "source_url": "https://www.nhs.uk/conditions/neck-pain-and-stiff-neck/",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "between-shoulder-blades",
            "region": "Neck, back & chest",
            "symptom": "Pain between the shoulder blades when lying down",
            "timing": "Any time in bed",
            "position": "not established",
            "mechanism": "Mid-back muscles and joints take load against the mattress, but mainstream sources do not tie this pain to any specific sleeping position.",
            "change": "no positional change described",
            "not_this": "Referred organ pain - angina, pleurisy, kidney trouble or an oesophageal spasm felt between the shoulder blades.",
            "red_flag": "Trouble breathing or chest pain, which could mean a heart attack or pulmonary embolism.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/symptoms/22866-upper-back-pain",
            "source_2_url": "",
            "source_note": "No authoritative source ties this to a sleeping position."
        },
        {
            "id": "shoulder-pain-night-only",
            "region": "Neck, back & chest",
            "symptom": "Shoulder pain only at night, cannot lie on it",
            "timing": "During the night",
            "position": "Lying on the affected shoulder",
            "mechanism": "A torn or irritated rotator cuff hurts at rest and at night. Lying on that shoulder compresses it, and gravity increases the pull on the tear.",
            "change": "Sleep with the injured shoulder facing up and the arm supported on pillows; on the back, a pillow under the arm. Avoid stomach sleeping.",
            "not_this": "Shoulder bursitis, including infected septic bursitis, which also hurts more when you lie on that shoulder.",
            "red_flag": "Sudden intense pain after a fall with snapping and immediate arm weakness or inability to lift, or fever.",
            "source_name": "AAOS OrthoInfo",
            "source_url": "https://www.orthoinfo.org/diseases--conditions/rotator-cuff-tears",
            "source_2_url": "",
            "source_note": "Night-only shoulder pain is a recognised rotator cuff pattern - this is not primarily a pillow problem."
        },
        {
            "id": "arm-aches-lying-down",
            "region": "Neck, back & chest",
            "symptom": "Arm aches when lying down at night",
            "timing": "During the night",
            "position": "Sleeping with the wrist bent or curled",
            "mechanism": "Bending the wrist during sleep raises pressure on the median nerve in the carpal tunnel, and pain or tingling can travel up the forearm toward the shoulder.",
            "change": "Keep the wrist in a neutral, unbent position during sleep rather than curled under you.",
            "not_this": "A pinched nerve in the neck sending burning pain and pins and needles down the arm.",
            "red_flag": "Numbness that is constant rather than coming and going, or visible thinning of the muscle at the thumb base.",
            "source_name": "AAOS OrthoInfo",
            "source_url": "https://www.orthoinfo.org/diseases--conditions/carpal-tunnel-syndrome",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "upper-back-lying-flat",
            "region": "Neck, back & chest",
            "symptom": "Upper back pain when lying flat",
            "timing": "Any time in bed",
            "position": "not established",
            "mechanism": "Lying flat leaves the mid-back's natural curve unsupported so thoracic joints and muscles take the load - though mainstream sources do not confirm this link.",
            "change": "Choose a mattress and pillow that support the spine's natural curves, keeping ears, shoulders and hips aligned.",
            "not_this": "Referred pain from the heart, lungs or kidneys, or inflammatory back pain that is worse with rest.",
            "red_flag": "Trouble breathing or chest pain, leg weakness or paralysis, or loss of bladder or bowel control.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/symptoms/22866-upper-back-pain",
            "source_2_url": "https://www.urmc.rochester.edu/encyclopedia/content?ContentID=4460&ContentTypeID=1",
            "source_note": "The alignment advice traces to URMC, not to the Cleveland Clinic page."
        },
        {
            "id": "lower-back-lying-flat",
            "region": "Neck, back & chest",
            "symptom": "Lower back pain when lying flat on your back",
            "timing": "Any time in bed",
            "position": "Lying flat on the back with the legs straight",
            "mechanism": "With the legs straight the lower back's inward curve is unsupported and the back muscles stay working. Bending the knees lets them relax.",
            "change": "Place a pillow under the knees when lying on the back; a small rolled towel under the waist can add support.",
            "not_this": "Inflammatory back pain such as ankylosing spondylitis, which is worse with rest and better with exercise.",
            "red_flag": "Numbness or weakness in both legs, numbness around the genitals or anus, or loss of bladder or bowel control.",
            "source_name": "NHS",
            "source_url": "https://www.nhs.uk/conditions/back-pain/",
            "source_2_url": "https://www.mayoclinic.org/diseases-conditions/back-pain/in-depth/sleeping-positions/art-20546852",
            "source_note": "Pillow-under-knees change traces to Mayo Clinic. Night pain alone was deliberately NOT used as a red flag - it produces many false positives for spinal malignancy."
        },
        {
            "id": "ribs-sore-side-sleeping",
            "region": "Neck, back & chest",
            "symptom": "Ribs sore from sleeping on your side",
            "timing": "On waking",
            "position": "Lying down on the affected side",
            "mechanism": "Rib cartilage irritated by small repeated stresses becomes tender, and lying on that side puts pressure and chest movement through it.",
            "change": "Avoid lying on the affected side - sources list it among the positions and movements that make the pain worse.",
            "not_this": "Costochondritis set off by infection, intense coughing or overexertion rather than by your mattress.",
            "red_flag": "Shortness of breath, palpitations, sweating, lightheadedness, nausea or a feeling of impending doom - call emergency services.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/diseases/22167-costochondritis",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "chest-wall-pain-side",
            "region": "Neck, back & chest",
            "symptom": "Chest wall pain when lying on your side",
            "timing": "Any time in bed",
            "position": "Lying down on the affected side",
            "mechanism": "Pain from ribs, cartilage and chest wall muscles is reproduced by pressure and chest movement, including the weight of lying on that side.",
            "change": "no positional change described",
            "not_this": "Heart attack, angina, pulmonary embolism, aortic dissection or pericarditis, which chest wall pain can closely mimic.",
            "red_flag": "Chest pressure or squeezing, pain spreading to arm, jaw, neck or back, shortness of breath, cold sweat - call emergency services.",
            "source_name": "American Heart Association",
            "source_url": "https://www.heart.org/en/health-topics/heart-attack/warning-signs-of-a-heart-attack",
            "source_2_url": "",
            "source_note": "Included for its red flag. Chest pain is never treated as a bedding problem on this site."
        },
        {
            "id": "neck-crick",
            "region": "Neck, back & chest",
            "symptom": "Crick in the neck from sleeping awkwardly",
            "timing": "On waking",
            "position": "Front sleeping, or the neck locked in an awkward twisted position during sleep",
            "mechanism": "The neck sits at an extreme angle for hours, so muscles and joints stiffen and turning the head becomes painful and restricted.",
            "change": "A low firm pillow with the head level with the body, a firm mattress, no front sleeping or neck twisting in bed.",
            "not_this": "Acquired torticollis from a throat or neck infection, arthritis, reflux or a medication reaction.",
            "red_flag": "Neck stiffness with fever, or a recent throat or ear infection, which points to infection rather than posture.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/diseases/22430-torticollis",
            "source_2_url": "https://www.nhs.uk/conditions/neck-pain-and-stiff-neck/",
            "source_note": "The sleeping-position link comes from the NHS page, not the Cleveland Clinic torticollis page."
        },
        {
            "id": "dizzy-rolling-over",
            "region": "Positional & whole body",
            "symptom": "Dizzy or spinning when you roll over in bed",
            "timing": "Any time in bed",
            "position": "Rolling over in bed, looking upward, or bending forward; prolonged bed rest is a documented risk factor",
            "mechanism": "Displaced calcium carbonate crystals float free in a semicircular canal, sending false rotation signals. An inner-ear problem, not bedding.",
            "change": "no positional change described",
            "not_this": "Meniere's disease or vestibular neuritis, causing vertigo lasting hours or days rather than seconds.",
            "red_flag": "Vertigo occurring independently of movement, gait disturbance, speech abnormality, or other neurological deficits.",
            "source_name": "StatPearls, NCBI Bookshelf",
            "source_url": "https://www.ncbi.nlm.nih.gov/books/NBK470308/",
            "source_2_url": "",
            "source_note": "Positional but not a pillow problem. Repositioning manoeuvres are clinician-performed and are deliberately not described here."
        },
        {
            "id": "vertigo-lying-down",
            "region": "Positional & whole body",
            "symptom": "Vertigo triggered by lying down on one side",
            "timing": "Any time in bed",
            "position": "Lying down or sitting up from lying; tilting the head back or to the side",
            "mechanism": "Loose crystals roll around in the semicircular canals and move the fluid, so the brain detects motion. The pillow is not the cause.",
            "change": "no positional change described",
            "not_this": "Labyrinthitis, vestibular neuritis or migraine as separate contributors to dizziness.",
            "red_flag": "Sudden vertigo with lightheadedness or nausea - contact a provider rather than adjusting bedding.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://my.clevelandclinic.org/health/diseases/11858-benign-paroxysmal-positional-vertigo-bppv",
            "source_2_url": "",
            "source_note": "Same as above - listed so readers can rule the pillow out, not so the site can treat it."
        },
        {
            "id": "acid-reflux-lying-down",
            "region": "Positional & whole body",
            "symptom": "Acid reflux when lying down",
            "timing": "During the night",
            "position": "Right side down is worst - lying right-side down increases nocturnal reflux and reflux after meals",
            "mechanism": "Lying flat removes the gravity that normally keeps stomach contents down, and right-side-down positioning lets acid pool against the valve and wash back up.",
            "change": "Sleep on the left side, elevate the head of the bed for night-time symptoms, and avoid meals within 2-3 hours of bedtime.",
            "not_this": "Cardiac or pulmonary disease; also achalasia, eosinophilic oesophagitis or functional heartburn, which mimic reflux.",
            "red_flag": "Difficulty swallowing, weight loss, GI bleeding, vomiting or anaemia - endoscopy as soon as feasible.",
            "source_name": "American College of Gastroenterology",
            "source_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC8754510/",
            "source_2_url": "https://pubmed.ncbi.nlm.nih.gov/37969463/",
            "source_note": "A 2023 systematic review found reduced acid exposure in left lateral versus right (mean difference -2.03, 95% CI -3.62 to -0.45) and no difference between right lateral and supine."
        },
        {
            "id": "heartburn-at-night",
            "region": "Positional & whole body",
            "symptom": "Heartburn at night",
            "timing": "During the night",
            "position": "Lying flat after a late evening meal",
            "mechanism": "Lying flat lets stomach acid move back into the oesophagus, and eating shortly before bed leaves a full stomach pressing against the valve overnight.",
            "change": "Elevate the head of the bed. Published figures disagree: about 6-10 in (ACG), 4-6 in (Mayo Clinic Health System), 10-20 cm (NHS). Wait 2-3 hours after eating.",
            "not_this": "Heart or angina pain - GERD chest pain can resemble angina and should not be assumed oesophageal until cardiac causes are excluded.",
            "red_flag": "Difficulty swallowing, food trapped behind the chest, vomiting blood, black tarry stools, choking, or weight loss.",
            "source_name": "American College of Gastroenterology",
            "source_url": "https://gi.org/topics/acid-reflux/",
            "source_2_url": "",
            "source_note": "Three mainstream bodies publish three different elevation figures. Recorded as a disagreement rather than resolved."
        },
        {
            "id": "hypnic-jerks",
            "region": "Positional & whole body",
            "symptom": "Body jerks as you fall asleep",
            "timing": "Falling asleep",
            "position": "not established",
            "mechanism": "In light sleep the brain may read the body as awake but the muscles as still, then signals muscle cells, producing a jerk or falling sensation.",
            "change": "no positional change described",
            "not_this": "Stress, caffeine, stimulant drugs, alcohol or lack of sleep driving the jerks, rather than anything about the bed.",
            "red_flag": "Jerks that regularly keep you awake, cause anxiety about going to bed, or become frequent.",
            "source_name": "Cleveland Clinic",
            "source_url": "https://health.clevelandclinic.org/why-do-i-feel-like-im-falling-when-im-falling-asleep-video",
            "source_2_url": "",
            "source_note": "Not positional - no sleeping position link described."
        },
        {
            "id": "heel-pain-first-steps",
            "region": "Positional & whole body",
            "symptom": "Heel pain on the first steps in the morning",
            "timing": "On waking",
            "position": "Sleeping with the feet pointed down",
            "mechanism": "Most people sleep with their feet pointed down, which relaxes the plantar fascia overnight, so the tissue is tight and painful when first loaded.",
            "change": "Night splints hold the foot instead of leaving it pointed down; the source describes them as very effective.",
            "not_this": "Insertional Achilles tendinitis, calcaneal stress fracture, or plantar nerve entrapment.",
            "red_flag": "Heel pain that persists - over 90% improve within 10 months of simple treatment, so lasting pain needs review.",
            "source_name": "AAOS OrthoInfo",
            "source_url": "https://www.orthoinfo.org/diseases--conditions/plantar-fasciitis-and-bone-spurs",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "hands-numb-wake-you",
            "region": "Positional & whole body",
            "symptom": "Hands numb and painful enough to wake you",
            "timing": "During the night",
            "position": "Sleeping with the wrists bent",
            "mechanism": "Many people sleep with their wrists bent, which increases pressure on the median nerve inside the carpal tunnel and provokes numbness and burning pain.",
            "change": "A brace or splint worn at night keeps the wrist straight or neutral while you sleep, reducing pressure on the nerve.",
            "not_this": "Associated conditions such as diabetes, rheumatoid arthritis or thyroid imbalance rather than sleep posture alone.",
            "red_flag": "Constant numbness, muscle weakness, loss of sensation, or wasting of the thumb muscles.",
            "source_name": "AAOS OrthoInfo",
            "source_url": "https://orthoinfo.aaos.org/en/diseases--conditions/carpal-tunnel-syndrome/",
            "source_2_url": "",
            "source_note": ""
        },
        {
            "id": "pillow-too-high",
            "region": "Positional & whole body",
            "symptom": "Signs your pillow is too high",
            "timing": "On waking",
            "position": "Back or side sleeping on too high or too stiff a pillow",
            "mechanism": "Too high or stiff a pillow keeps the neck flexed overnight, which can result in morning pain and stiffness. Imaging studies describe the cervical spine bending forward, with T1 slope and C2-7 Cobb angle increasing.",
            "change": "Back sleepers use a rounded pillow supporting the neck's natural curve, with a flatter pillow under the head.",
            "not_this": "None described by the source.",
            "red_flag": "None described by the source.",
            "source_name": "Harvard Health Publishing",
            "source_url": "https://www.health.harvard.edu/pain/say-good-night-to-neck-pain",
            "source_2_url": "https://pubmed.ncbi.nlm.nih.gov/34683013/",
            "source_note": "Harvard gives mechanism and fix but no differential or red flag - left empty rather than filled in. Imaging detail from a 2021 Healthcare review."
        },
        {
            "id": "pillow-too-low",
            "region": "Positional & whole body",
            "symptom": "Signs your pillow is too low",
            "timing": "On waking",
            "position": "Side sleeping on a pillow that lets the head sink too far toward the mattress",
            "mechanism": "A pillow that lets the head sink toward the mattress takes the head out of neutral, so the neck is no longer aligned with the body. Imaging describes the cervical spine stretching backward.",
            "change": "Choose a pillow that keeps the head neutral, with head and neck aligned with the rest of the body.",
            "not_this": "Psychological stress, or daytime posture such as screen height or carrying heavy bags.",
            "red_flag": "Neck pain with fever, headache, leg weakness, unexpected weight loss, arm or jaw pain, or neck immobility.",
            "source_name": "Sleep Foundation",
            "source_url": "https://www.sleepfoundation.org/sleeping-positions/best-sleeping-position-for-neck-pain",
            "source_2_url": "https://pubmed.ncbi.nlm.nih.gov/34683013/",
            "source_note": "Imaging detail from a 2021 Healthcare review."
        },
        {
            "id": "shoulder-numb-side",
            "region": "Positional & whole body",
            "symptom": "Shoulder goes numb when sleeping on that side",
            "timing": "During the night",
            "position": "Side sleeping on the affected arm, or with the arm under the head, body or pillow",
            "mechanism": "Falling asleep on the arm stretches and compresses the nerves and reduces blood flow to the area, producing numbness.",
            "change": "Avoid sleeping with the arm under the head, body or pillow, and avoid bent wrists and elbows. Back sleeping minimises numbness.",
            "not_this": "Carpal tunnel syndrome or peripheral neuropathy rather than simple positional compression.",
            "red_flag": "Numbness lasting more than a few minutes after changing position, weakness, movement problems, or numbness in several areas.",
            "source_name": "Banner Health",
            "source_url": "https://www.bannerhealth.com/healthcareblog/teach-me/how-to-prevent-your-arms-from-falling-asleep-at-night",
            "source_2_url": "",
            "source_note": ""
        }
    ]
}