Hi, Thanks for reaching out. I am glad to hear that you are overall healthy and take good care of your diet. But there can be a few factors which can increase the risk of heat stroke and they include:- 1.Dehydration- Due to less water intake. 2. Staying in apartments which are not well ventilated. 3. Certain medications like anti-allergy medicines, medicines for psychological conditions and a few more. 4. Chronic health conditions- diabetes, hyperthyroidism etc. 5. Sudden change in climate or difficulty of body to adjust in high temperature regions. In your case, as you mentioned that you perspire very little... so, less sweating can be one of the causes of heat stroke because sweating helps to cool down the body. I have seen that some people are unable to adjust to sudden change in temperature and may get heat stroke, if they suddenly get exposed to a high temperature. So, the causes may be vivid and it may be hard to point out a specific cause but good to stay safe and prevent heat stroke. I would recommend you to stay hydrated, wear loose, cotton, light colored clothes, wear a good sunscreen while going out in sun and use some hat or umbrella. Can you relate to any of the risk factors for being more to heat stroke, which I mentioned above? Please do reply, would love to discuss more with you about this.