Altitude has long been viewed as the holy grail for endurance training. The lower levels of oxygen high in the mountains produce a state of hypoxia in the body that triggers the production of red blood cells. More RBC's equal more oxygen being delivered to muscles and therefore higher performance. The measure of oxygen being delivered to muscles is known as V02.
Unfortunately this process can take weeks, if not months, to show any viable increase in performance. Unless you live in the Rockies or the Sierra's, you will likely never see a change in V02 from altitude training on and off. Rather, it seems as though an unexpected training variable could be a better solution to increasing V02: heat.
According to Santiago Lorenzo, a former decathlete at the University of Oregon and a professor of physiology at Lake Erie College of Osteopathic Medicine, “heat acclimation provides more substantial environmental specific improvements in aerobic performance than altitude acclimation."
So how does heat effect performance?
There seem to be two primary mechanisms of adaptation that heat triggers:
- An increased ability to adapt to a wider range of temperatures
- An increase in blood plasma volume
Chris Minson is a professor of human physiology at the University of Oregon who studies heat acclimation in athletes. Beyond an increase in blood plasma volume, Minson has found what he describes as inexplicable changes to the heart’s left ventricle, which seem to increase oxygen delivery to the muscles. Further, his research shows that heat training can allow athletes to begin to sweat sooner and at a higher rate, while also maintaining an overall lower body temperature.
But is it bad for you?
Overheating and dehydration are two very serious risks involved with heat training. Further, they can lead to or trigger a vast number of health complications so consulting your doctor and working with a trained coach is always important in regards to endurance training.
Training with heat, however, seems to be one of the safest tactics for increasing V02. According to a study done at James Cook University in Cairns, Australia, short-term heat training provided cyclists with a 6% drop in 5km TT times, while showing no signs of negative effects on athlete's immune systems.
Heat training has been a key component of my program for years now. Living in snowy Tahoe, I started doing it each winter to make the first races of the year down in sunny/warm Spain or Cyprus less of a shock to the system. However, with the more I learned about it, it soon became a year-round staple of my training.
While I will occasionally visit a dry sauna, my preferred method of heat training is Bikram Yoga, 1-2 times per week. The sessions are 90 minutes long in a heated room, with a trained professional guiding you through both the heat, limiting your hydration, as well as a spine-focused strength and stretching routine.
I try to avoid brutally hot days on the bike. When it is 100 degrees during the summer, I try to ride early in the morning and get out of the sun before the peak temps hit. Heat is taxing and can have negative immediate effects on power output and performance. Because of this, I keep my heat training and my on-the-bike training separate as best I can. This way I can get the most out of each, rather than doing them both poorly.
If yoga isn't your thing, I'd recommend contacting a cycling coach in regards to sauna visits. Temperature, duration, and hydration practices will vary a lot from athlete to athlete, but they'll be able to get you started in the right direction.