With heatwaves becoming more frequent around the world, times can be trying, especially for people with obesity. Being overweight may affect a person’s heat tolerance, making them more susceptible to heat stress.
Studies have observed that overweight people are more prone to developing heat stress. According to a 2018 study published in the journal Nature, body temperature is strongly associated with obesity markers in men and postmenopausal women.
Dr Beverly Tchang, endocrinologist, Weill Cornell Medicine, New York, says, intermediate factors related to thyroid hormone or menopause may be mediators, which explains why some people with obesity feel hot or cold all the time. “Severe hypothyroidism, for example, presents with both cold intolerance and excess weight, while menopause, often presenting with hot flashes, is a period when women can experience weight gain in addition to heat intolerance,” she adds.
How does fat affect body temperature?
Dr Ramen Goel, a bariatric surgeon from Mumbai, says, people with obesity have fat deposited under the skin that provides insulation. “Adipose tissue or body fat is a bad conductor of heat, thereby acting as an insulator. This may be the reason why people with obesity are more affected by heat,” he adds, explaining that if there’s a couple in a room, the person with obesity might need more air conditioning (a lower temperature), while the other person might feel very cold.
According to an article published in the journal Handbook of Clinical Neurology in 2018, excised fat tissue has a lower thermal conductivity than excised lean tissue. In theory, subcutaneous fat might act as a barrier to heat loss and influence thermoregulatory abilities.
Dr Tchang, also a member of the Obesity Society, says, “In theory, excess subcutaneous tissue may impair heat dissipation, and cold exposure has been demonstrated to increase the activity of brown adipose tissue [type of body fat that regulates body temperature in cold climates]. However, cold interventions have not been shown to result in substantial weight loss.”
She adds, anecdotally, that while individuals with obesity may be sensitive to heat, there is no robust scientific evidence to prove a direct causal relationship. Also, obesity may not affect the core body temperature, and there may not be a direct relationship between heat intolerance and body temperature as well. Citing an example, Dr Tchang says, “Consider a person with fever and chills. He/she has an elevated body temperature, but reports feeling cold.”
Dr Goel says that to manage heat stress, one can avoid stepping out when it is too hot, avoid dehydration by drinking lots of water and remain in an air-conditioned environment. “The best thing for an overweight person in the long run would be to lose weight, as it can help with heat intolerance and excessive sweating,” he adds.
Takeaways
- Obesity can make one more susceptible to heat stress.
- Body fat is a bad conductor of heat, thereby acting as an insulator. This can be the reason why people with obesity have a lower heat tolerance.
- To manage heat stress, one can avoid stepping out in the hot sun and ensure adequate hydration. However, the best thing for an overweight person in the long run would be to lose weight.
