Hello,
Since you have anhidrosis, excessive exercise can cause heat exhaustion and heat stroke. To prevent this, avoid excessive exercise, exercise in cooler climate, drink plenty of water, wear appropriate clothing and avoid drinking caffeine or alcohol as these liquids are dehydrating. Also get an evaluation done from a physician and check out the possible cause of anhidrosis.
It may be caused in autonomic neuropathy like diabetes, alcoholism, Sjogren’s syndrome(an autoimmune disease causing inflammation and decreased secretions by certain glands of the body) and Ross syndrome(a peripheral nerve disorder) and certain skin conditions. I feel that a clinical evaluation and investigations are needed in confirming a diagnosis. Please consult a physician/neurologist for the same.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
You will probably just have to focus on your diet mostly. If you do exercise keep it light and for short periods at a time in a cool area where other people are around. Take a cool washcloth and put it around your neck. Cooling these major blood vessels in your neck will help cool down your body. Wear clothes that breathe easily and are light. There are thousands of diets to choose from, but I would suggest Weight Watchers because they teach you how to maintain a diet, not just crash diet. Good luck!