Head swelling may be caused by physiological factors, but also by abnormal blood pressure, atherosclerosis and other factors. 1. Physiological factors: when the weather is too hot, it may lead to skin vasodilatation, so that the blood supply to the brain is insufficient, which leads to head distension, generally in the body after cooling can gradually improve, do not need to worry too much. 2. Abnormal blood pressure: hot weather can increase the probability of high blood pressure in hypertensive patients, so hot head swelling may be caused by elevated blood pressure; low blood pressure patients in hot weather peripheral vasculature is easy to dilate, which will lead to lower blood pressure, and so there may also be hot head swelling. 3. Atherosclerosis: Atherosclerosis patients in the heat of the day, the probability of vascular spasm is large, it is easy to lead to the heat of the day head swelling. After eliminating physiological factors, patients should consult a doctor in a timely manner and follow the doctor’s instructions to standardize the treatment in order to prevent the condition from worsening. In addition, in the heat of the day should do a good job of cooling and preventing heatstroke, in order to prevent physical discomfort.