In my experience, doing 3-6 reps is the sweet spot for this type of training. As this is done in a circuit fashion with incomplete rest, you'll be unable to perform the same loads as during traditional lifting sessions.
The water on your body changes to a gas called water vapor. Water turns into a gas through a process called evaporation. Heat makes water evaporate faster. All air has some water vapor. Tropical rain forests and deserts are both hot.
The amount of water vapor in the atmosphere exists in direct relation to the temperature. If you increase the temperature, more water evaporates and becomes vapor, and vice versa. So when something else causes a temperature increase (such as extra CO2 from fossil fuels), more water evaporates.