Heat and exercise. From Bikram yoga to ultramarathons

Heat and exercise. From Bikram yoga to ultramarathons

Being too warm seems a distant memory at this time of year – with ‘Blue Monday’, dark days and damp, cold weather, it is hard to envisage being too hot. Dull January seems to be an excellent time to think about ways to exercise in the warm.

Here in the UK we may be preoccupied with keeping warm, but in the southern hemisphere it is mid-summer. Those who have been following events at the Australian Tennis Open will know that the feasibility of exercise in extreme heat is very much on the agenda there.

The Australian Open is held in Melbourne, a city notorious for extremes of temperature and sudden changes in weather. The outside temperature can vary by fifteen or twenty degrees in a matter of hours, especially in summer which is when the tennis event takes place. The stadium does have a retractable roof, but unlike the one used at Wimbledon its main purpose is to shield from heat, not rain.

Last year’s Wimbledon tournament was held in unusually high temperatures for the UK, although there was no disruption to the event. This is partly because professional tennis players at this level live in an endless summer as they travel the world, and most are acclimatised to high temperatures. However this is not the case for ball boys, officials and the crowd, and there comes a point where the players will start to suffer. The ‘trigger temperature’ for this at Melbourne is kept secret, although it was reached at the 2014 event resulting in postponement of matches.

What are the effects of exercising in heat? On the positive side, muscles are kept warmer and so protected from injury, and with no demand to maintain body temperature more resources can be diverted to movement. However the body must be able to lose the heat generated by exercise, otherwise there will be problems. In extreme circumstances this leads to heat stroke and collapse, and is a medical emergency.

There have been many studies carried out to try to find out if exercising in heat is beneficial, or if it makes for a higher calorie burning rate. There is some evidence that the increased heart rate helps to raise the intensity of the workout. The extra sweating can provide additional ‘cleansing’, although the effect is fairly minimal. It is also suggested that a hot workout is healthier simply because many common disease-causing organisms cannot survive in the elevated temperature (which is why our bodies develop a fever when we are ill).

For those who would like to try a ‘hot workout’, here are some of the available options.

  • Bikram yoga is carried out in a room heated to a toasty 40 degrees centigrade with 60% humidity. The sweating that is an inevitable by-product of this is said to speed up the elimination of waste products from the body, in the same way that a sauna is believed by some to promote health. The heat of a Bikram room can be very uncomfortable for those un-acclimatised to it, but participants are encouraged to stay for the full ninety minutes of the workout for the full benefit. 
  • ‘Hot spinning’ is a variation on the popular exercise-bike class, carried out in a heated room. This can be achieved in warmer countries or in the summer simply by turning off the air-conditioning that is normally needed in a gym.
  • Pilates has also been adapted for heated rooms. The workout is not aerobic, but builds core strength and flexibility. Higher room temperature allows greater muscle stretching and hence improves the results of the workout.

These gym-based exercises will be plenty for most of us, but the idea of exercising in the heat can be taken much further. Some international events are held purely to present a chance for athletes to pit themselves against extreme heat levels.  If a normal hot workout is no longer challenging, how about one of these?

  • The Marathon des Sables (‘race of the sands’) is a five-day event held in Morocco, with competitors running through the desert carrying everything that they need, except water. Competitors sleep in tents and are provided with water rations at regular checkpoints.
  • Even more extreme is the American Badwater Ultramarathon, which takes competitors from below sea level in Death Valley to the top of Mount Whitney. To add to the challenge, the route has several climbs and descents, and so totals a distance of 217 kilometres and a total ascent of nearly 6000 metres. Competitors have support crews as well as regular checks.
  • The above events are in low-humidity areas – this can be easier to tolerate as there is some cooling effect from sweat.  The Ironman Triathlon held on Hawaii adds the extra challenge of humidity, as well as a tough open-water swim and a cycling section. The course moves from the beaches of the ‘Big Island’ of Hawaii to the volcanic bad lands further inland.

Perhaps it is best to start in that nice warm gym!



Frank H.
31 January 2014

Frank H.

The main thing to keep in mind with all these hot exercises is hydration. You can put yourself in serious danger if you go too far. I'm a big fan of bikram yoga but it took some time to get used to.

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