Heat is the New Altitude

For years now athletes have been packing up and heading to altitude training camps in the hope of gaining an edge on the competition. For most athletes altitude gains are limited to sleeping on the top bunk as a kid.

But now recent research has unveiled a new frontier in training environment performance boosting.
Heat! Training in heat brings benefits to athletes competing in any climate, hot or cold and the benefits can act as an accelerator to early season adaptations as well as late season race preparation. But as with any training modality, comes with its drawbacks.

Heat and exercise

To understand the benefits and complications of heat training we need to understand the mechanics of what is happening to the body during exercise in hot environments.

When the body over-heats the following physical responses occur, leading to decreased performance.

• Excessive sweat loss (and electrolyte loss)
• Cramping
• increased core temperature
• Decreased blood flow (due to loss of blood plasma volume)
• Longer recovery time (due to dehydration)
• You get all sweaty and gross and stuff.

Benefits

Heat training acclimatisation effects the mechanisms involved with cooling the body, making them more efficient. As well as stressing the physiological factors involved with delivery of blood and oxygen to working muscles.

Increased sweat rate: During exercise evaporation accounts for 80% of heat loss. This would be where sweat is so important. As a result of heat training the body adapts to produce more sweat and produce it earlier on during exercise. meaning more efficient cooling sooner.

This may seem counter intuitive, why would losing more water be beneficial, wouldn't that make me more dehydrated?

Well just hold your horses because this next point is going to knock your compression stockings off.


Hypotonic sweat: Another clever adaptation to heat training is a decrease in the amount of electrolytes lost in sweat. (most importantly sodium) Losses of electrolytes can be hard to replace during exercise due to the physical demands of the activity hampering digestion and are a likely cause of cramping and or impaired performance.

Less blood flow to skin: This might sound insignificant, but less blood to the skin means more blood to the working muscles. This occurs as a result of the body's increased ability to cool itself without sending blood to the skin surface.

This also means less red faces and less filters are required to make post run Instagrams look good.

Decreased HR: This can be due to a number of factors. One of the proposed theories is that a decrease in sweating leads to a greater blood plasma volume, meaning blood can more easily flow. and if blood flows more easily its less work for whatever it is that pumps the blood...

Recommendations

Heat acclimation

•  6 - 14 days (the best benefits come after about 2 weeks. (extended periods of training in extreme heat may lead to a decrease in session quality) 
• At least 60 mins a day and should increase body, skin and core temperature and induce sweating
• Should be targeted to replicate environment of completion
• 30-40 deg C (humidity can effect this)
• Ensure proper hydration and recovery.

Benefits generally last for 2-4 weeks however in this time athletes can build on these adaptations further. Re-acclimatising is also quicker if it has already taken place previously.

Some other practical recommendations for those on a budget

• Find the air con remote in the office and crank the heat, if anyone asks, tell them you're an ironman, that should confuse them for a while
• sneak your wind trainer into a bikram yoga class
• In summer always park your car on the roof of the car park at shopping centres
• When you leave the house in the morning, leave the oven on. if the house doesn't burn down you will return to a toasty kitchen
• Ask your gym if you they will kindly move the treadmill into the sauna.

McArdle, W. D., F. I. Katch, et al. (2010). Exercise Physiology: Energy, Nutrition, and HumanPerformance. Baltimore, Maryland, USA, Williams and Wilkins. Chapter 25

S. Racinais, J. M. Alonso, A. J. Coutts, A. D. Flouris, O. Girard6, J. González-Alonso, C. Hausswirth, O. Jay 9, J. K. W. Lee, N. Mitchell, G. P. Nassis, L. Nybo, B. M. Pluim, B. Roelands, M. N. Sawka, J. E. Wingo, J. D. Périard, (2015), Consensus recommendations on training and competing in the heat, Scand J Med Sci Sports Vol. 25 pp. 6–19