Rheumatoid arthritis (RA) causes pain, inflammation, and swelling in the joints. Some people with RA report experiencing heat intolerance, although it is not a common symptom.

A person with heat intolerance has an unusual sensitivity to heat and may feel hot when others find the temperature comfortable.

Heat intolerance has several possible causes. Medical experts do not typically associate it with RA, even though some people with RA report heat intolerance.

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RA is an autoimmune inflammatory disease in which the immune system mistakenly attacks healthy cells. This can lead to painful joint inflammation and damage to joint tissue over time.

Some people with RA and other types of inflammatory arthritis report feeling unusually hot. Some describe their heat intolerance as constant, while others report intense flashes of heat that may worsen during arthritis flare-ups.

Heat intolerance is an unusual sensitivity to heat that can show up differently from person to person. Someone with heat intolerance may feel very hot even in moderate temperatures or have extreme physical reactions to warm weather, such as excessive sweating and dizziness.

Despite reports of heat intolerance from some people with RA, health authorities such as the Centers for Disease Control and Prevention (CDC) and arthritis organizations like the Arthritis Foundation do not list it as a common symptom.

Experts do not know how or why RA may cause heat intolerance, and there is a lack of research on potential links between the two conditions. Possible explanations include:

  • Autonomic nervous system (ANS) dysregulation: People with seropositive RA are more prone to ANS dysfunction. This can cause heat intolerance and difficulty with temperature regulation.
  • Inflammatory cytokines: The immune system increases the production of proteins called cytokines when a person has inflammation from arthritis. Inflammatory cytokines may increase body heat, which could contribute to heat intolerance.
  • Fever: Some people with RA experience a low grade fever. This may be due to certain inflammatory cytokines interacting with areas of the brain that control body temperature. However, some people describe feeling overheated without having a fever.
  • Menopause: Some people with RA report symptoms of heat intolerance that are similar to the hot flashes and night sweats that can occur during menopause. Experts do not know how or why RA may cause hot flashes. Menopause may be the more likely cause of heat intolerance in people who have RA and are going through menopause.

There is a lack of research on the possible links between heat intolerance and arthritis, and there are no specific symptoms of RA-related heat intolerance.

In one older study from 2014, 4.6% of older people with osteoarthritis, another type of inflammatory arthritis, reported that hot weather affected their pain levels.

People with RA have anecdotally reported symptoms such as:

  • a constant feeling of being overheated
  • flares of intense heat
  • a feeling of heat in the hands and feet
  • a feeling of heat throughout the body
  • night sweats

Generally, signs of heat intolerance include:

Although there is a lack of evidence for how or why RA may cause heat intolerance, a person can take steps to manage heat sensitivity in general, such as:

  • avoiding the sun during the hottest times of the day
  • drinking plenty of fluids
  • avoiding strenuous activity in warm environments
  • using a fan or an air conditioner during hot weather
  • wearing light, loose-fitting clothing
  • taking a cool bath or swimming
  • avoiding caffeine and alcohol
  • putting a cool, wet towel or ice pack on the head or the back of the neck

A person should contact a doctor if they experience persistent symptoms of heat-related illness, such as:

A person should seek immediate medical attention if they or someone else experiences symptoms of severe heat-related illness, such as:

  • confusion
  • loss of consciousness
  • a temperature higher than 103°F (39°C)
  • an inability to sweat, even when very hot

Below are the answers to some frequently asked questions about RA.

Is summer worse for rheumatoid arthritis?

In general, studies suggest that people with RA experience worse symptoms and more flares when temperatures are lower during the colder months rather than during summer. But scientists do not understand the exact connection between weather and arthritis.

Can rheumatoid arthritis cause sweating at night?

Although night sweats are not a common symptom of RA, some people with the condition report experiencing them.

What are some unusual symptoms of rheumatoid arthritis?

What is the best climate for rheumatoid arthritis?

According to the Arthritis Foundation, warmer, drier climates may be the best for people with RA.

Some people with rheumatoid arthritis (RA) report experiencing symptoms of heat intolerance, such as excessive sweating, intense flares of body heat, and a tendency to feel unusually hot in temperatures that others find comfortable or cool.

However, there is a lack of research on possible connections between RA and heat intolerance. Experts do not know how or why RA may contribute to heat intolerance, and health authorities do not typically list it as a common symptom of RA.

Inflammatory cytokines may influence body temperature in people with RA. Low grade fever due to RA, as well as menopause, may also play a role in heat intolerance. However, more research is necessary to determine links between RA and heat intolerance.