Playing characteristics and workload in a sport vary between players, positions and playing styles. Sports are often played in an inside environment where conditions of heat, humidity, and airflow differ substantially from field conditions. Athletes may wear team uniforms and gear for protection, sponsorship, or tradition, rather than for consideration of heat transfer. Sports originating in cool climates often have rules and traditions that may not be suited to hot environments. Matches played close together in tournaments may lead to chronic dehydration.
Some sports impose rules to prevent athletes drinking during a play period.
We were surprised by the scarcity of data from actual competitions, and by the failure of these data to cover the range of environmental conditions and levels of play that are of interest. Our impression is that fluid intake generally falls behind sweat loss during team games, and that moderate to severe dehydration can occur. We also noted that data on the use of carbohydrate-containing drinks to promote fuel replacement during matches are not available. The main reason is probably that performance is difficult to measure in team sports. In most other sports, the athlete competes as an individual and achieves a certain time, distance or weight.