Last updated 2026-07-11

Can people with autoimmune conditions use a sauna?

Yes, many can. The word "autoimmune" covers more than 80 distinct diseases ^[1], and one blanket answer for all of them is a mistake. Someone with psoriasis and someone with multiple sclerosis are in completely different situations the moment they sit down in a 185°F Finnish sauna. The risks are real for some diagnoses, mild or close to nothing for others, and for a few conditions the research actually leans in favor of heat.

Here's the honest summary. Heat therapy has a long history in European rheumatology, and some genuinely careful studies back it for conditions like ankylosing spondylitis and psoriasis. But for diseases where heat rapidly worsens neurological symptoms (MS above all) or where fever-like states can set off systemic flares (lupus), the math changes.

This article goes condition by condition, uses real data where it exists, and tells you what honest precautions look like. It does not replace your rheumatologist's advice. That relationship matters more than anything written here.

Why does heat affect autoimmune conditions differently?

Heat raises body temperature, and body temperature changes a lot of things at once: nerve conduction speed, inflammatory cytokine activity, blood viscosity, immune cell behavior. In healthy people those shifts are temporary and the body pulls itself back to baseline fast. In autoimmune disease the baseline is already dysregulated, so a big thermal load can push things in directions nobody can fully predict.

The best-studied mechanism is the Uhthoff phenomenon, named after Wilhelm Uhthoff, who described it in 1890. In MS the myelin sheaths are damaged, and even a modest rise in core temperature (as little as 0.5°C, roughly 0.9°F) can block electrical conduction in partially demyelinated nerve fibers ^[2]. That's why heat reliably worsens MS symptoms for a while. It isn't an immune flare in the inflammatory sense. It's a conduction block. Symptoms usually fade as temperature normalizes, but the experience can be frightening, and it stays a real safety concern.

Inflammatory arthritis reads differently. In rheumatoid arthritis (RA) and ankylosing spondylitis (AS), heat can loosen muscle spasm, improve joint mobility, and dull pain. A 2009 study in Clinical Rheumatology found that four weeks of combined spa and exercise therapy produced significant drops in pain, fatigue, and disease activity scores in AS patients ^[3]. The inflammatory driver in those diseases doesn't seem to get acutely worse from the moderate heat used in therapeutic settings.

Lupus (SLE) brings a separate worry: heat exposure mimics fever, and fever can trigger lupus flares. Photosensitivity is also common in SLE, affecting roughly 40 to 70% of patients ^[4], and infrared sauna panels emit wavelengths that may reach deeper into skin than sunlight does. Traditional steam saunas and infrared saunas are not the same thing, and that difference matters more for some diagnoses than others.

Which autoimmune conditions make sauna higher-risk?

Condition	Primary concern	Evidence level
Multiple sclerosis (MS)	Uhthoff phenomenon: heat worsens nerve conduction	Strong mechanistic evidence [2]
Systemic lupus (SLE)	Heat may trigger flares; photosensitivity with IR sauna	Moderate (case reports + mechanism) [4]
Myasthenia gravis	Neuromuscular transmission impaired by heat	Moderate (clinical consensus)
Sjögren's syndrome	Dehydration risk amplified; autonomic dysfunction common	Moderate
Systemic sclerosis (scleroderma)	Impaired thermoregulation; vascular complications	Moderate
Dermatomyositis / polymyositis	Active myositis may worsen with heat stress	Low (limited data)

MS is the standout, the one condition with the clearest documented reason for caution. Many neurologists tell MS patients to skip traditional high-heat sauna entirely during a relapse and to use only low-temperature or cooling protocols (sometimes called cool-down sauna or contrast protocols) when in remission ^[2]. The question that decides everything: is the patient in a stable phase or an active relapse? Heat during active neurological inflammation carries more risk.

Lupus patients are a big group, roughly 1.5 million Americans have SLE ^[4], and the sauna question comes up constantly. The fear isn't that sauna causes lupus or wrecks organs in a single session. The real concern is that heat stress and a raised body temperature can turn up certain immune pathways that are already dysregulated in lupus, and that repeated exposure over days to weeks might nudge someone toward a flare. Nobody has clean randomized trial data on this exact question. The closest guidance comes from the general heat-avoidance advice built into lupus management.

1x/week (reference)	0%
2-3x/week	24%
4-7x/week	40%

Source: Laukkanen et al., JAMA Internal Medicine, 2015

Which autoimmune conditions may actually benefit from sauna?

Psoriasis has the strongest case. Finnish sauna culture has overlapped with psoriasis care for decades, and dermatology research broadly supports the observation that heat and sweating can improve psoriatic plaques. A small but well-designed study in Acta Dermato-Venereologica found improvements in skin symptoms with regular sauna use in psoriasis patients ^[5]. The proposed mechanism: heat increases local circulation, speeds skin cell turnover, and may briefly quiet the hyperproliferative activity behind psoriatic lesions. Psoriatic arthritis adds a joint layer, but most rheumatologists treating PsA don't call sauna off-limits if the patient handles heat well.

Ankylosing spondylitis (AS) has reasonable evidence behind heat therapy. The spine and hip stiffness that defines AS softens with warmth in most patients. Morning stiffness is notoriously worse in the cold, and heat helps people get moving enough to do the physical therapy that actually slows the disease. The 2009 Clinical Rheumatology study above ^[3] used combined spa therapy, which isn't the same as sauna, but heat was the core ingredient.

Rheumatoid arthritis in stable, controlled disease is generally considered safe for moderate sauna use. Finland has one of the world's highest rates of both sauna use and RA (RA affects about 1% of the global population ^[6]), and Finnish rheumatologists have folded heat therapy into care for generations without disaster in that patient population. The caveat lives in the words "stable and controlled." Anyone in an active RA flare with hot, swollen joints should wait.

Inflammatory bowel disease (Crohn's and ulcerative colitis) sits in a real gray zone. Heat and dehydration can set off gut symptoms, and some IBD patients find sauna destabilizing. Others use it with no trouble. There's basically no good trial data here, and individual response matters more than any general rule.

For a wider look at what heat therapy does to the body, see our sauna benefits guide.

What precautions should autoimmune patients take before a sauna session?

Start with your rheumatologist, neurologist, or whoever manages your condition. Not a general practitioner who sees you once a year, but the doctor who knows your disease activity, your current medications, and your recent labs. Some immunosuppressants (methotrexate, mycophenolate, azathioprine, newer biologics) change sweating, thermoregulation, or cardiovascular response in ways that reshape the risk of heat exposure ^[7].

Beyond that conversation, these precautions show up again and again across clinical guidance.

Start cooler than healthy users do. Many sauna guides recommend 170 to 195°F for Finnish saunas. A reasonable starting point for autoimmune patients is 120 to 140°F, the range used in many therapeutic settings. Traditional saunas run as hot as they run, but infrared saunas dial down to lower temperatures, which is one reason some practitioners prefer IR for therapeutic use in this group. Our sauna vs steam room piece walks through the tradeoffs between types.

Cut sessions hard. Healthy adults often do 15 to 20 minute rounds. For autoimmune patients starting out, 5 to 8 minutes fits better. Build slowly over weeks based on how you actually feel, not on what you think you should be able to handle.

Never go alone. This applies to most special populations using heat, but it counts double for anyone whose condition can bring sudden neurological symptoms, dizziness, or cardiovascular swings. Someone needs to be within reach.

Hydrate before and after. Patients on diuretics, anyone with kidney involvement (lupus nephritis is common), and anyone with autonomic dysfunction need extra care. Drink 16 oz of water before you get in, keep water nearby, and hydrate again afterward.

Skip sauna during active flares. This one is simple and holds across every condition. If you're flaring right now, this is not the week to start or continue sessions.

Watch for warning signs. Unusual weakness, vision changes, heart palpitations, severe dizziness, a sudden jump in any neurological symptom, or the feeling that you're about to pass out. Get out at once if any of these hit, and don't go back in that day.

Does the type of sauna matter for autoimmune conditions?

It does, and this question gets less attention than it deserves. The type shapes how fast your core temperature climbs, and core temperature is what drives most of the risk.

Traditional Finnish dry saunas run hot (150 to 200°F) at low relative humidity. Steam rooms (hamam-style or wet sauna) run cooler (100 to 120°F) but near 100% humidity. Infrared saunas run at 110 to 150°F and heat the body through radiant energy rather than heating the air. Each triggers a different physiological response.

For MS patients, all three raise core temperature, so the Uhthoff mechanism applies to every type. The lower operating temperature of infrared might look like an edge, but you can still push core temperature up plenty in an IR sauna if you stay long enough. Temperature on the thermostat doesn't decide the risk. Duration and the change in core temperature do.

For lupus patients with photosensitivity, infrared raises a legitimate question. Near-infrared wavelengths (roughly 700 to 1400nm) reach deeper into skin than most UV light, and there is some evidence that IR radiation can set off Toll-like receptor-mediated immune responses in the skin that could matter for photosensitive patients ^[8]. This is not proven harm in a clinical setting, but it's enough that some dermatologists steer SLE patients toward traditional dry sauna over infrared if they use sauna at all.

For psoriasis, both anecdotal and some study-level evidence favor traditional Finnish sauna, partly because that context has been studied the most ^[5].

Steam rooms occupy an odd spot. The lower temperature feels easier, but the high humidity blocks evaporative cooling from sweat, so core temperature can climb just as fast as in a hotter dry sauna. If you're using heat mainly for joint mobility and pain, a steam room at 110°F for 10 minutes may be safer than a 185°F Finnish sauna for 5. Total thermal load is what counts.

If you're weighing options, our home sauna guide covers how the different types work and how to judge them before buying.

Are there specific medications that change sauna safety for autoimmune patients?

Yes, and this is one of the most under-discussed parts of the whole conversation.

Common autoimmune medications that interact with heat exposure include the following.

NSAIDs (ibuprofen, naproxen, diclofenac). These lower fever and inflammation, which can mask warning symptoms like overheating. You may feel fine longer than you should. They also carry renal effects that combine badly with dehydration from sweating.

Corticosteroids (prednisone, methylprednisolone). Chronic steroid use weakens the body's control of blood pressure and electrolyte balance. Fluid and sodium loss in a sauna can drop blood pressure hard in steroid-dependent patients.

Hydroxychloroquine (Plaquenil). Common in lupus and RA. It can cause QT prolongation in some patients, and heat stress also affects cardiac electrophysiology. The combination is worth a specific talk with your prescriber.

Biologics (TNF inhibitors like adalimumab and etanercept, IL-6 inhibitors, JAK inhibitors). These suppress specific immune pathways. No direct evidence says heat destabilizes biologic therapy, but immunosuppressed patients have less reserve for handling infection or physiological stress. Some biologics also raise cardiovascular event risk, and heat is a cardiovascular stressor ^[7].

Methotrexate. Hepatotoxic in high doses. Heavy dehydration from sauna concentrates the drug's metabolites. Stay well hydrated.

Diuretics (furosemide, hydrochlorothiazide). Sometimes used in lupus or RA patients with edema. Sauna plus diuretics is a real dehydration risk.

Bring your current medication list to the specialist conversation about sauna. Don't assume they'll run through every interaction for you. Bring the specific question.

Can sauna use trigger an autoimmune flare?

This is the fear most patients carry, and the honest answer is: possibly, for certain conditions and circumstances, but the evidence for a direct causal link is weak across most autoimmune diseases.

For MS, a single heat exposure rarely triggers a true relapse, which involves new inflammatory lesion formation. The temporary symptom flare-up from Uhthoff phenomenon fades with cooling and usually isn't a new relapse. Some neurologists still worry that repeated heat stress during a vulnerable stretch could act as a cofactor. The evidence there is largely expert opinion, not trial data ^[2].

For lupus, the heat-triggered flare concern is more mechanistically plausible. Heat shock proteins (HSPs) go up with thermal stress, and HSPs have been implicated in SLE pathogenesis through several pathways ^[9]. Whether a recreational sauna session raises HSPs enough to matter clinically is unknown. What is known: many lupus clinicians advise heat avoidance during high disease activity as standard practice.

For RA in a stable phase, occasional sauna use doesn't appear to cause flares in published reports. The bigger issue is comfort during a flare (inflamed joints and heat are a miserable pairing) rather than immunological harm.

For psoriasis, sauna looks more likely to help than hurt, based on existing data ^[5]. A flare after sauna in psoriasis would be unusual.

The working principle: if you feel meaningfully worse in the 24 to 48 hours after a session, more than just tired, a genuine bump in disease symptoms, that's a signal to stop and talk to your specialist. Your own response to trial sessions tells you more than any general guideline.

What does the research actually say about heat therapy and autoimmune disease?

The honest verdict: the research base is thin relative to how common these conditions are. Large randomized controlled trials of sauna in specific autoimmune populations are almost entirely missing. What exists falls into a few buckets.

Spa therapy and balneology studies, mostly from European centers, show benefits for AS and RA, but they usually bundle heat with mineral baths, exercise, and other elements. Isolating the sauna's contribution is hard. The 2009 Clinical Rheumatology study by van Tubergen et al. ^[3] is one of the better-designed examples.

Infrared sauna in cardiovascular and pain conditions is a separate line of work. A 2015 JAMA Internal Medicine study on sauna frequency and cardiovascular mortality in Finnish men ^[10] gets cited constantly for sauna benefits in general. It didn't study autoimmune patients, but it set out the epidemiological safety profile of regular sauna use in a large general population (2,315 men over 20 years). The study reported that "men who had 4-7 sauna sessions per week had a 40% lower risk of all-cause mortality" compared to once-weekly users. That's a striking result from a real, large cohort, though correlation doesn't prove the sauna caused the benefit.

Case reports and small series for specific conditions (psoriasis, AS) point toward benefit ^[3][5], but they carry less evidentiary weight.

For MS specifically, the Uhthoff literature is mechanistically solid but gives no actionable dosing: how much heat is too much, for which patients, stays undefined.

So here it is. The research supports cautious, individualized use for most stable autoimmune conditions, clear caution for MS, and genuine uncertainty for lupus and scleroderma. Anyone who tells you the evidence is settled in either direction is overstating it.

How should autoimmune patients start using sauna safely?

Assume you're starting from scratch even if you used saunas before your diagnosis, because your pre-diagnosis physiology isn't your current physiology. Here's a realistic protocol structure drawn from the physical therapy and rheumatology literature.

Weeks 1 to 2: one session a week, 5 to 8 minutes, temperature at or below 140°F. Go with someone present. Sit on the lower bench, where the air is cooler. Cool down slowly afterward with room-temperature water, not ice cold, to avoid abrupt cardiovascular changes. Track symptoms for 48 hours in a simple written log.

Weeks 3 to 4: if nothing worsened, add a second weekly session or stretch each one by 2 to 3 minutes.

Month 2 onward: adjust based on your consistent response. Many autoimmune patients settle around 10 to 12 minutes at 130 to 150°F, 2 to 3 times a week. Some never get comfortable going higher, and that's fine.

Don't try to push through discomfort as if it proves toughness. For autoimmune conditions, discomfort in the sauna is a real signal, not something to override.

SweatDecks carries a range of home sauna options, including infrared models with precise temperature control, which makes this kind of careful step-by-step titration far more practical than trying to manage a commercial gym sauna's thermostat.

For sessions that include a cool-down phase, our cold plunge guide covers how cold exposure works physiologically. Full contrast therapy is a more advanced step that autoimmune patients should run past their specialist before adding.

Is there any autoimmune condition where sauna is flatly contraindicated?

Most official medical organizations haven't published absolute condition-by-condition bans on sauna use. The American College of Rheumatology (ACR) publishes treatment guidelines for specific diseases but has no ACR guideline specifically on sauna as of this writing ^[6]. The National Multiple Sclerosis Society recommends that MS patients avoid overheating and advises caution with hot tubs, baths, and saunas, especially during relapses ^[2].

In practice, many neurologists treat sauna as effectively off-limits during MS relapses, even though that exact language doesn't appear in a formal guideline. That's the right call.

Myasthenia gravis is another. Heat's impairment of neuromuscular transmission is documented well enough that most neuromuscular specialists advise against any heat exposure that raises core temperature much. The Myasthenia Gravis Foundation of America has published guidance on heat avoidance for exactly this reason.

Systemic sclerosis (scleroderma) involves fibrosis of skin and internal organs and badly impaired thermoregulation in many patients. The ability to sweat is often compromised, which removes the main cooling mechanism that makes sauna tolerable and safe in the first place. Most scleroderma specialists would advise against traditional sauna.

For everyone else, the answer is "discuss with your specialist" rather than a hard no, with the caveat that an active flare of any autoimmune condition is a strong reason to postpone.

What warning signs should make an autoimmune patient stop mid-session?

Get out of the sauna at once, and don't go back in that day, if any of these show up.

Sudden neurological symptoms: numbness, tingling, vision changes, sudden weakness, or trouble with coordination. For MS patients these may clear with cooling, but they signal your system is reacting to heat in a real way.

Heart palpitations or a sense of irregular heartbeat. Heat lowers blood pressure and speeds heart rate. If your heart feels like it's racing or skipping, get out.

The feeling that you might faint, or a sudden cold sweat (paradoxical sweating can come right before syncope).

Nausea or vomiting. Heat-related illness often shows up first as nausea.

Skin color changes. Flushing is normal. Pallor, going pale, is not, and it points to vascular compromise.

Chest pain. Not "I'm hot and uncomfortable," but actual chest pain.

Sudden worsening of joint pain that feels different from your usual stiffness. Sharp joint pain during a session is worth taking seriously.

After any of these, cool down gradually (no immediate ice-cold immersion), drink water, lie down, and call someone if you don't feel clearly better within 10 to 15 minutes. If symptoms are severe or won't resolve, get emergency care. Heat stroke, a core temperature above 104°F with neurological symptoms, is a medical emergency ^[11].

Frequently asked questions

Can I use a sauna if I have rheumatoid arthritis?

Probably yes, with caveats. When RA is in stable remission and well controlled, moderate heat therapy is generally considered safe and may reduce joint stiffness. Avoid sauna during active flares when joints are hot and swollen. Start at lower temperatures (around 130 to 140°F) and shorter sessions (5 to 8 minutes), and get your rheumatologist's sign-off, especially if you're on biologics or methotrexate.

Is sauna safe for people with multiple sclerosis?

Traditional high-heat sauna is generally not recommended for MS patients, especially during relapses, because even a small rise in core temperature (0.5°C) can temporarily worsen nerve conduction in demyelinated fibers, the Uhthoff phenomenon. Some people with stable MS tolerate brief sessions in lower-temperature infrared saunas. The National MS Society recommends avoiding overheating. Talk to your neurologist before trying any heat therapy.

Can lupus patients use a sauna?

Lupus (SLE) patients are generally advised to be cautious with heat. Heat can mimic fever, which may trigger flares, and photosensitivity affects 40 to 70% of SLE patients, raising questions about infrared sauna exposure in particular. No large trial proves sauna causes lupus flares, but the mechanistic concern is real enough that most lupus specialists recommend avoiding heat stress during active disease and checking in before using sauna in remission.

Does sauna help psoriasis?

There's meaningful evidence that it does. Regular sauna use is associated with improvement in psoriatic plaques in small but real studies, and the combination of heat, increased circulation, and sweating may reduce hyperproliferative skin activity. Psoriasis is one of the autoimmune conditions where sauna appears more likely to help than harm, though individual response varies and starting conservatively is still smart.

What temperature sauna is safe for autoimmune conditions?

Most therapeutic heat protocols for autoimmune conditions use 110 to 140°F, well below the 170 to 195°F of traditional Finnish saunas. At that range you still get meaningful effects (increased circulation, muscle relaxation, sweating) with less risk of rapidly raising core temperature. Infrared saunas dial to lower temperatures more easily, one reason some practitioners favor them for this population.

Can sauna use trigger a lupus flare?

It's possible but not clearly proven. Heat stress raises heat shock proteins, which have been implicated in SLE pathogenesis, and fever is a known lupus flare trigger. Whether recreational sauna sessions raise HSPs enough to cause a clinical flare hasn't been studied well in controlled trials. Practical advice: avoid sauna during high disease activity, watch for worsening symptoms in the 48 hours after any session, and discuss with your rheumatologist.

Is infrared sauna better than traditional sauna for autoimmune patients?

It depends on the condition. Infrared saunas run at lower temperatures (110 to 150°F vs 150 to 200°F for traditional Finnish saunas), making temperature control easier and thermal load potentially lower. That's often an advantage. But for lupus patients with photosensitivity, some dermatologists prefer traditional sauna because near-infrared wavelengths may interact with immune pathways in skin. There's no single right answer across all autoimmune conditions.

How long should an autoimmune patient stay in a sauna?

Start with 5 to 8 minutes maximum for the first several sessions. Healthy adults often do 15 to 20 minute rounds; that's not a fitting starting point for most autoimmune patients. If you handle 5 to 8 minutes well with no symptom worsening in the following 48 hours, extend gradually by 2 to 3 minutes per week. Many autoimmune patients find a sustainable session runs 10 to 12 minutes, not longer.

Can I do contrast therapy (sauna and cold plunge) with an autoimmune condition?

Contrast therapy is more physiologically demanding than sauna alone, so treat it as an advanced step. The rapid temperature swings put significant strain on the cardiovascular system and aren't appropriate for many autoimmune patients without explicit specialist guidance. If you've used sauna consistently for weeks without trouble, contrast therapy might be a future option to discuss with your doctor. Cold exposure alone has its own evidence base; see our cold plunge guide.

Do immunosuppressant medications make sauna more dangerous?

They can. Corticosteroids impair blood pressure regulation and electrolyte balance. Methotrexate combined with significant dehydration raises toxicity concerns. Some biologics increase cardiovascular risk, and heat stress is a cardiovascular stressor. NSAIDs can mask overheating symptoms. Bring your complete medication list to any conversation with your specialist about sauna. Never assume a medication has no interaction with heat without checking.

What should I do if I feel worse after a sauna session with an autoimmune condition?

Track exactly what worsened: fatigue that cleared within an hour (likely normal heat response), or a genuine increase in disease symptoms lasting into the next day? If you have a clear symptom flare in the 24 to 48 hours after sauna, stop sessions and contact your specialist before going back. For MS patients, neurological symptoms that don't clear after cooling down within 30 to 60 minutes warrant a call to your neurologist the same day.

Is it safe to use a sauna if I have ankylosing spondylitis?

AS is one of the conditions with the most favorable evidence for heat therapy. Warmth reduces the morning stiffness that's central to AS and may help patients tolerate the physical therapy that actually modifies disease progression. A 2009 study in Clinical Rheumatology showed spa therapy with heat produced significant improvements in AS patients. Standard precautions (lower temperature, shorter sessions, avoid during flares) still apply.

Can children with autoimmune conditions use a sauna?

There's essentially no pediatric-specific research on sauna use in juvenile autoimmune conditions. Children thermoregulate differently from adults and are more prone to heat illness. For juvenile idiopathic arthritis or pediatric lupus, the answer is clearly "only with explicit guidance from the treating pediatric rheumatologist." Do not apply adult protocols to children here.

Sources

1. NIH National Institute of Environmental Health Sciences, Autoimmune Disease: The NIH identifies over 80 distinct autoimmune diseases affecting millions of Americans.
2. van Tubergen A et al., Clinical Rheumatology, 2009, Spa therapy combined with exercise in ankylosing spondylitis: A 2009 Clinical Rheumatology study found four weeks of combined spa and exercise therapy produced significant reductions in pain, fatigue, and disease activity scores in ankylosing spondylitis patients.
3. Acta Dermato-Venereologica, Sauna and psoriasis (study indexed at PubMed): A study published in Acta Dermato-Venereologica found improvements in skin symptoms with regular sauna use in psoriasis patients.
4. American College of Rheumatology, Rheumatoid Arthritis disease information: Rheumatoid arthritis affects approximately 1% of the global population; the ACR provides disease management guidance used by U.S. rheumatologists.
5. FDA, Drug Interactions: What You Should Know: Medications including immunosuppressants, corticosteroids, and NSAIDs can alter physiological response to heat stress through effects on blood pressure regulation, electrolyte balance, and cardiovascular function.
6. Hamblin MR, Photobiomodulation review, NIH PubMed Central: Near-infrared wavelengths (700-1400nm) penetrate skin more deeply than UV and can trigger Toll-like receptor-mediated immune responses in skin tissue.
7. Journal of Autoimmunity, heat shock proteins and autoimmunity (indexed at PubMed): Heat shock proteins upregulated by thermal stress have been implicated in SLE pathogenesis through several immune pathways.
8. Laukkanen JA et al., JAMA Internal Medicine, 2015, Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events: The 2015 JAMA Internal Medicine study of 2,315 Finnish men over 20 years found that men who had 4-7 sauna sessions per week had a 40% lower risk of all-cause mortality compared to once-weekly users.
9. CDC, Extreme Heat: Signs and Symptoms: Heat stroke is defined as a core body temperature above 104°F accompanied by neurological symptoms and is classified as a medical emergency requiring immediate care.
10. National Multiple Sclerosis Society, Heat and Temperature Sensitivity: The Uhthoff phenomenon means a rise in core temperature as small as 0.5°C can temporarily worsen nerve conduction in MS; the National MS Society advises avoiding overheating, especially during relapses.
11. Lupus Foundation of America, Lupus facts and photosensitivity: Roughly 1.5 million Americans have SLE, and photosensitivity affects an estimated 40 to 70% of lupus patients.

"