Fig. 2.

Frequency histograms of (a) forearm sweat sodium concentration ([Na⁺]) using the absorbent patch technique and (b) predicted whole-body sweat [Na⁺] from 506 athletes (367 adults, 139 youth; 404 male, 102 female) of various sports (e.g. American Football, basketball, baseball, soccer, tennis, and endurance) tested during training or competition in various environmental conditions (15–50 °C, 20–79% relative humidity). The vertical line represents the mean value. Reproduced from Baker et al. [96], with permission