It depends on the amount of Radiation. To put it in context,: radiation is a via where energy (normaly in the form of heat) flows. Some energy, is good, too much energy is dangerous.
Advantages of radiation: Good mood, rise in methabolism, help to warm muscles up, good stomach digestion.
Disadvantages of radiation: cancer, skin disease, headaches, burns, dehydratation.
The Ultraviolet B (280-315 nm) sector of the Solar Spectrum causes problems to the human body, especially to the skin, eyes and Immunologic system.
In order to know quickly the health risk from UV-B radiation, we use the UV Index.
According to the UV Index, a value less than 3 means no risk, between 3 and 6 implies a moderate risk and greater than 6 means high risk. A value greater than 11 means EXTREME risk. In the tropics is not strange to find values greater than 15.
there are models for heat transfer from human bodies. metabolism and fat burning mechanisms will be affected by heat gain and sweating mechanisms. see attached paper.