Cape Town, South Africa
The upside of training in the heat

In South Africa we have started to move into the part of the year where runners are heading out earlier in the morning to avoid the heat. While the west coast of South Africa still experiences mostly mild conditions compared to the east coast, catching the sun when it is high can turn the mildest of runs into a sufferfest.

These negative effects of running in hot humid conditions explain why the struggle is real:

  • Impaired aerobic performance

  • Decreased VO2 max

  • Reduced drive from the central nervous system leading to early onset of fatigue

  • Faster depletion of glycogen stores

All good reasons to avoid the heat.  However, our marvelously complex bodies adapt really well and really fast to heat exposure and if you are medically sound and have no risk factors preventing you training in the heat, you will not only be able to adapt to becoming more comfortable in the heat fairly quickly, but you will acquire performance boosting adaptions which will help you run faster in temperate conditions.


How quick is quick? A large percentage of the adaptations already occur in the first week of heat exposure with 10 - 14 days being optimal for near to complete adaptation and adaptation peaking at around 3 weeks.


The main adaptations that take place are:

  • Enhanced sweating and skin blood flow

  • Plasma volume expansion
  • Better fluid balance (hydration) and cardiovascular stability
  • Acquired heat tolerance

all of which result in performance enhancing adaptations such as: 

  • A decrease in core temperature

  • Increased control of cardiovascular function
  • Increased sweat rate with earlier onset and more dilute sweat
  • Improved submaximal exercise performance
  • Increased VO2 max`
  • Improved thermal comfort in the heat

In a  study involving a group of athletes doing 3 weeks of interval training in (a) heat (33 degrees), (b) heat and altitude (c) temperate conditions - The group training in heat showed the greatest improvement over a 3km time trial (an average of 5% improvement). Interestingly, combining heat with altitude showed less of an improvement than only heat. This shows that heat training could provide a simple way of enhancing performance. Could heat training be the new altitude training?


So next time you are tempted to rather jump in the pool with a cold beer, think of all the performance enhancing benefits you could get from some hot weather runs.


Onwards and upwards! 

Coach Kathleen