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Many people with MS find that heat can cause their symptoms to worsen. This might involve a build up of fatigue, blurred vision, loss of balance or a worsening of cognitive symptoms such as concentration or memory. The effect of temperature changes on visual symptoms is known as Uhthoff's phenomenon.

Although unpleasant, the effects of heat are temporary and do not cause any permanent damage to nerves. The symptoms are generally quickly reversed when body temperature returns to normal.

Many people who are sensitive to heat find that cooling techniques can reduce problems. This can involve cooling whilst doing activities, using a mister spray or cooling gel in wristbands or scarves. Alternatively, some people find cooling down before activity, by having a cold bath or shower or by using a cooling suit, gives them more energy or stamina.

Whilst a reaction to increased heat is more common, some people with MS find that a decrease in temperature also causes a worsening of symptoms.


  • Davis SL, et al. Thermoregulation in multiple sclerosis. Journal of Applied Physiology 2010;109(5):1531-1537. Full article

Last updated: 8 June 2015
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