Substitute blogger here and boy is it hot. How hot is it you say? Its so hot I saw two trees fighting over a dog.
So how does this heat effect our running? Our bodies have tremendous capacity to regulate our body temperature and we can therefore tolerate very high temperatures. It is very likely that humans are more able to deal with intense heat than any other complex animal. There are several methods your body uses to handle high temperatures.
The first method is to influence our behavior with unpleasant sensations in response to heat. Our response to such behaviors may be to move into shade, drink cold fluids, take off clothing, wearing a hat, ect. This is the most efficient, effective and immediately available method of temperature regulation.
The second method of dealing with the heat is to use our blood to move heat from the more critical and heat sensitive areas of our body such as the organs and brain to the less critical such as the skin. This is done by constricting and dilating blood vessels. Increasing the blood volume near the surface of the skin increases the heat and this causes it to radiate heat away from the body. There is significant short term damage to the areas of the body that experience elevated temperatures. The body compensates and even mitigates that damage with a family of substances called heat shock proteins. The body has a limited reserve of hsp and it will increase that reserve in response to repeated or sustained heat stress. This makes an adequate intake of protein as well as an adequate period of acclimation to the heat important.
The third method is evaporation. The body secretes liquid on the skin and through breathing as this liquid turns to a gas is absorbs heat energy. In cold weather our capacity to sweat is about a liter per hour. In hot weather our capacity can double or triple on a time frame of up to six weeks. The biggest factor in the increased capacity to sweat is an increased ability of your body to limit electrolyte loss through sweating. Electrolytes are a critical nutrient to body functioning and you body will stop sweating is your electrolyte levels get to low. You body knows what foods or beverages have the electrolytes and will make you desire those sources when it needs more.
Now we come to the greatest enemy of high temperature running, air conditioning. It we want our bodies to adapt to the high temperatures then we should not be in low temperature environments most of the time. As I type this I am sitting in a 90 degree room with a fan directly on me. My hair is short, I am wearing flipflops, shorts and a T shirt and I am very comfortable. My kids are actively playing and laughing and are not suffering from the heat. I do not think twice about stepping outside to tend my garden and the heat registers to me but it is not unpleasant. If you are used to an air conditioned house I am sure you will suffer a great deal when you step out of you cool dry house into the hot, humid outside. If you cannot give up air condition then you can gradually turn it to higher temperatures and supplement with fans, cold drinks, and heat appropriate clothing.