Essentially, the exercise volume is a function of the intensity of exercise, the duration of exercise, and the frequency of exercise.

从本质上讲，运动量是运动强度、运动持续时间和运动频率的函数。

Whether they need it depends on the climate, type and intensity of exercise, and whether they are prone to sweat heavily.

具体取决于气候、运动类型和强度，以及是否容易出汗。