Obesity is a common cause of heat intolerance, and high cortisol levels are often associated with obesity [source: Vaughan]. So, one way to help your body adapt to temperature increases could be to lower your cortisol levels.
Also known as glucocorticoid, cortisol is a hormone that increases blood sugar. While this is a normal function within the body, it can get out of hand. In people who experience chronic stress, anxiety or depression, cortisol levels can increase. When cortisol levels are elevated, they can sometimes lead to weight gain [source: National Institutes of Health]. So it stands to reason that targeting cortisol may help you lose weight and thus reduce your risk of heat intolerance.
Adrenal adaptogenic herbs are sometimes recommended for the treatment of stress and high cortisol. Rather than one specific supplement, there are a range of adrenal adaptogenic herbs that include Asian ginseng, licorice root, suma and others. You should visit a homeopathic doctor for recommendations on the combination best for you. In fact, it's always a good idea to seek out a doctor's guidance and supervision when taking supplements.
If stress is your problem, you might be able to use the supplement on the next page as well.