By Rob West
Core Temperature – Why is it so important to performance?
During strenuous exercise the body’s heat production may exceed 1000 W, some of this energy is stored and raises the body’s core temperature by a few degrees. Resting internal body temperature is around 37°C and when it is raised the body has a number of thermoregulatory reflexes. These include increased skin blood flow and sweating, which help your body lose heat.
This is important, because as your core temperature rises too high your cerebral motor cortex act to reduce voluntary muscle activation in order to limit the accumulation of heat and prevent injury. Put simply, your body starts to shut down so you don’t do yourself any serious damage. Therefore your ability to control your core temperature is a direct limiter to your performance. This is especially true when competing in hot and humid conditions, like Vietnam. Additionally when competing in hot and humid conditions, your body faces a number of cardiovascular limitations, impairing oxygen delivery by the blood and the ability of the exercising muscles to uptake oxygen.
Heat Training – Yeah it sucks, but the rewards are great!
There are a number of things we can do to help this situation, heat training being one of them. Exercising/training in the heat improves heat tolerance by increasing the sensitivity of the sweat rate/core temperature relationship, decreasing the core temperature threshold for sweating and increasing total blood volume. Training in the heat can create larger plasma volume in the blood and may help display better central venous pressure and cardiovascular stability under heat stress.
If you never train in the heat of the day, prefering to do your running early in the morning or once the sun has set, you are never giving your body the chance to acclimatise to exercising in the heat. Once you have acclimatised blood volume increases, resting core temperature decreases, as does the concentration of sodium in sweat and urine. You train your sweat glands to produce more sweat and your maximal sweat rate increases. As a result, core temperature and cardiovascular strain are reduced because evaporative heat loss capacity is enhanced.
Infrared Saunas – Isn’t there another way?
Luckily there is another way for those who just can’t face lacing up their running shoes and heading out into the midday heat. Saunas, steam rooms, hot baths, but much much more effective, infrared saunas. All of these help your body tolerate greater levels of hyperthermia (overheating of the body), if they are used regularly. However the infrared sauna is king.
An infrared sauna works by emitting infrared light to warm your body directly, as opposed to a traditional sauna, which heats the air around you. This allows you to stay in the sauna longer and as a result tolerate a higher rise in core temperature. Other benefits useful to athletes are the relief of sore muscles and joint pain, improved circulation and detoxification.
This particular sauna can help with inflammation due to its full spectrum as in Far, Mid and Near Infrared. The combination of Far and Mid together has superior inflammation and pain reduction penetrating soft tissue.
But please note you will not feel many benefits from one session alone. Regular sessions 2-3 times a week for a period of at least 1 month should be implemented so you can feel the real potential of their use.
So there you have it. Why core temperature and your body’s ability to regulate it has a massive impact on your athletic endeavours, why you need to start training in the heat and how the regular use of infrared saunas are a key tool, that after personally benefiting from, I cannot recommend highly enough.
Want to learn more about core temperature and racing in the heat. Prolonged exercise in the heat is an excellent article featured in Sports Medicine Journal by Julien Périard.