From Charles Babbs, West Lafayette, Indiana, US
Alice Klein’s story about a man who was genetically destined to develop Alzheimer’s but didn’t after working for two decades in sauna-like, hot engine rooms makes perfect sense physiologically. The cardiovascular effects of such hot conditions are similar to those of exercise: greater total-body blood flow, faster heart rate, stronger heartbeat, a larger difference between maximal and minimal arterial pulse pressures, and consequent greater pulsatile expansion of brain arteries. This radial pulsation of arteries in the brain drives the glymphatic pump that flushes Alzheimer’s-causing tau proteins from brain tissue (9 May, p 4). If hot, arduous work is not for you, keep on running!
