Heat Training Improves Blood Volume in Athletes

Heat exercise training usually refers to exercise training conducted in the heat while athletes spend the reminder of the day in temperate conditions.

In most recent studies, exercise training sessions conducted in the heat are typically 45-60 min in duration, performed at low exercise intensity and 5 times per week. Since then main aim with this type of training is to increase core temperature, most heat training sessions have been performed immediately after the athletes ordinary training (where core temperature is likely higher) and is seen as a supplement to their existing exercise training regimes.

1-2 weeks of heat exercise training has been conducted for decades and is shown to increase plasma volume and exercise capacity when athletes are tested in a warm environment. More recent studies have demonstrated that 5 weeks of heat training may also facilitate Hbmass and thereby possible also exercise performance in a cool environment.

Since the aim with heat training is to increase body core temperature, heat training does not necessarily have to be performed in a warm environment but may also be conducted in a cool environment with the addition of garments that prevent heat loos during exercise.  Importantly, since during outdoor cycling wind cooling is substantial, most studies have been performed with athletes training indoor on ergometers, rollers or treadmills since wind cooling is less. Wearing garments during exercise to stimulate heat training in a cool environment seems an attractive alternative to performing heat exercising training in a climatic chamber, and can also rather easily be brought on travels and training camps.

Following heat training, Hbmass has been shown to increase to a similar extend as from altitude exposure and could therefore become an alternative to altitude training camps.

It is currently speculated if heat training conducted during high altitude training camps may be beneficial, or if heat training could be used after altitude exposure to limit the rapid loss (1-2 weeks) of red blood cells upon returning to sea level.

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