RickInOz

You will remember that I recently complained about the unseasonal heatwave striking Adelaide. The average temp for this month so far is 37 degrees.

Despite the heat, the need for exercise mustn’t stop, but I’m struggling badly to keep up my usual form. Even with the aircon running the exercise studio at our gym has regularly been uncomfortable in the past month or two. There is a reasonable amount of evidence that increased temperature impairs exercise capacity. When revising for my anaesthetic exams I learnt that neutral environmental temperature for humans is around 25 degrees. This is the temperature at which the body does not need to burn calories to generate body heat and is able to tolerate exercise comfortably. Inevitably with exercise, core body temperature rises, and this presents the body with the problem of dissipating it. As the ambient temperature rises, the differential decreases and so the ability to lose heat diminishes.

The problem is often exacerbated by dehydration and failure to compensate for insensible losses (i.e.: evaporation from expired breath and sweat). Dehydration can have a significant adverse effect on exercise capacity, time to fatigue and muscle strength. In dehydration, the body attempts to compensate with a reduction in sweating, which only exacerbates a rise in core temperature. Hyperthermia is a major problem if uncompensated and can lead to headaches, dizziness and confusion.

This means I will either have to stop going to the gym - not an option - or find a way of acclimatising to the weather. As always, Google came to the rescue and found the advice given to Australian athletes before leaving the Antipodean winter for the dry climate. Recommendations included:

1. Clothing:
   • Expose as much skin as possible to allow sweat to evaporate more easily
   • Wear synthetic fabrics that draw sweat away from skin and allow it to evaporate quickly
   • Wear loose fitting clothes that allow convection of hot air through collars and sleeves
2. Fluid intake:
   • Drink plenty throughout the day preceding exercise so you are starting from a well-hydrated state
   • Drink plenty during exercise. Although difficult to keep up with fluid losses, it will help prevent dehydration
   • Avoid food shortly before exercise, as it will delay gastric emptying and reduce ingested water available for absorption
   • Unless exercise is prolonged, free water is the best fluid as that is what is being lost. The salt content of sweat is low during exercise and the Western diet usually contains excess salt hence deficit is uncommon
3. Enviromental optimisation:
   • If possible workout in the coolest room or studio available.
   • Stand near fans or aircon outlets to make the most of the “wind chill” factor
   • Arrange gym sessions for early morning or late evening when the ambient temperature will be lowest
4. Acclimatisation:
   • The only way to get used to exercising in heat is exposure to those conditions. With repeated sessions it is possible to achieve improved tolerance and hence performance

Either way I’m still finding it difficult, and the change in weather can’t come soon enough. Having said that, if I can continue to lift the same weight in this heatwave perhaps an increase will be possible when it breaks.