Call an ambulance and evacuate the victim to a hospital. If you can't control temperature or humidity in your workplace, you must become acclimatized to it. Acclimatization is the ability to perform a maximum amount of strenuous work in the heat by gradually getting yourself used to the climate in which you must work. First, get yourself into good physical condition. Physical work in the heat is necessary for full acclimatization, but should consist of increasingly longer work periods each day, alternating with rest or lighter work.
Some workers reach full acclimatization within a week, while others take longer.
If you go on vacation, remember, you will start losing your resistance to heat after one week and you'll lose it completely in a month's time. In this case, rest means minimal activity, not stopping work completely. Workers may alternate light and heavy work, indoor and outdoor work, etc. Duties may also be rotated among several workers to protect them from heat, changing work shifts to avoid excessive afternoon heat for outdoor workers, and workload can be adjusted based on body size or physical strength. Most people don't realize that hot food adds directly to body heat.