Q: Tucson summers are quite hot and sometimes I feel sluggish not only in my body but also in my mind. Does living in the desert heat affect brain function?
A: Our bodies shiver to warm up and sweat to cool off without any conscious control. This temperature regulation occurs in the hypothalamus, a small region of your brain that helps your brain communicate with hormone-release cells throughout your body and acts as a thermostat to keep your body temperature within close range of 98 degrees Farenheight. While it’s only a small percentage of your total body size, your brain is a metabolic hotspot, burning through 20% of the calories you consume each day. And thinking, just like when exercising, can produce a spike in heat. Your brain needs to shed all the extra heat and it does so through circulating blood with cooler, oxygenated blood from the lungs. If your body temperature is high due to exercise, infection, or external weather conditions, your brain may not be able to cool itself as well. But what happens in a too-warm brain? Excessive or prolonged heat can cause neurons to malfunction, producing seizures and even death. But smaller increases in brain temperature (mild hyperthermia) may affect the brain by changing how proteins fold and function, and thus how neurons communicate with each other. Not all proteins are affected equally and it seems that some key proteins that are important for cell function are particularly vulnerable to heat. Why would some of your most important proteins be heat-sensitive? Well, it seems these proteins are generally very flexible and the ability to change confirmation is crucial to their important function in cells. Unfortunately, this also makes them very sensitive to heat-induced changes in confirmation. Behavioral studies indicate body temperatures around 101 degrees fahrenheit can impair memory. However, some of these effects can be mitigated by providing water, suggesting dehydration may contribute to the thinking issues we experience with heat.
Author: R. Keating Godfrey, PhD