• Heat acclimatisation
• olympics
• heat stress
• training
• testing

The 2020 Tokyo Olympics will be held from 24 July to 9 August, in hot and humid environments, in the world’s largest metropolitan area. Two years to the day before the 2020 Olympics, temperatures surpassed 41°C with over 65 heat-related deaths recorded in a single week. Protecting the health and performance of the athlete under these conditions is a shared responsibility among the International Olympic Committee (IOC), the local organiser (LOC), the International Federations (IFs), the National Olympic Committees (NOCs), the national federation medical staff, the coaching staff and the athletes themselves. Unfortunately, these various stake holders do not always have the appropriate information to adopt the necessary preventive countermeasures. Following the motto ‘By failing to prepare you are preparing to fail’ (Benjamin Franklin, 1706–1790), a series of editorials will be published between now and the Olympics with clear information for practitioners on how to prepare.

First of all, endurance and team sports athletes should be aware that heat stress dramatically decreases performance. Fortunately, the acute effects of heat stress can be progressively attenuated by repeated training in …