Investigating passive heating as a heat acclimation strategy for endurance athletes

The research explored passive heating by hot-water immersion (HWI) as a heat acclimation (HA) strategy for endurance athletes residing in cool environments. Heat acclimation involves repeated heat exposure to induce beneficial adaptations for subsequent exercise in the heat. Different time delays between exercise and HWI were explored, as well as the effects of daily HWI in a training scenario. The results of the research indicated that HWI should be conducted immediately after exercise to maximise the heat load. Additionally, a 2-week pilot training study with 39°C HWI of increasing duration did not induce significant adaptations in 12 recreational male runners.