**10. Oral rehydration during exercise**

Based on the physiological responses to warm and hot conditions described previously, it is suggested that dehydration prior to and during exercise should be prevented or countered. This would reduce extra thermal and cardiovascular strains during exercise in the heat and the risk of developing heat-related illnesses. In general, oral rehydration with solutions containing 0.1–0.2% of NaCl and 4–8% of CHO based on thirst sensation is recommended, but, during exercise, we need to prevent the addition of 2% of body weight reduction [7]. Elderly persons or persons who work or undertake high-intensity exercise in warm and hot conditions should start fluid ingestion prior to and during the early period of work before thirst is perceived [7]. Special care should be taken by diabetics so that hyper and hypoglycemia are not induced with oral rehydration during exercise and hyperthermic conditions.
