<span>A rain gauge is an instument used to measure the amount of liquid precipitation over a certain length of time. In its simplest sense, a rain gauge is nothing more than a can which collects water which falls from the sky as rain. The depth of the rain can be measured with a ruler.</span>
The answer is to increase the minutes in which he is doing the exercise. He can just increase it by a couple of minutes and he will gradually improve his endurance.
