As discussed in Chapter 7, sweat is a combination of mostly water and electrolytes. Water is needed to help remove the excessive heat generated from the body during exercise. One liter of sweat allows for the removal of 580 calories of heat from the body. So, if an activity such as running for 2 hours generates about 900 calories of heat, then theoretically about 1.5 liters of sweat may have been lost. The primary electrolytes lost from the body in sweat are sodium and chloride. However, their concentration in sweat is lower than in the plasma of the blood. Thus, sweat is dilute compared to blood. Even when someone is sweating profusely, the sodium and chloride content may be only about one-half of the concentration of human blood plasma.
Was this article helpful?