After 2019 Athletics World Championships in Qatar, the 2020 Olympic Games will take place in Tokyo where again weather conditions could be extreme in all outdoor sports. Some radical schedule changes (night races, early start,…) limit the risk of heat-related illnesses, but high temperature and humidity remain a serious concern for endurance athletes. Some valid countermeasures like heat acclimation, ice vests and baths, ice slurry ingestion will be implemented by elite athletes and their staff. New biomedical devices like ingestible pills, sweat analysers, thermal camera, specifically designed clothing, and handheld electrolyte or thermic analysers are also used to either conduct researches for better preventive actions, or optimise the treatment of athletes suffering from heat stroke. Global warming on one hand, and exponential growth of the number of endurance races on the other hand, will for sure bring heath-related illnesses and their prevention at the forefront.