Having lived in Botswana for several years, I know what dry heat is. The name is fairly self-explanatory; the air simply lacks moisture.
However, dry heat is actually better for your health than ‘wet heat’, or humid weather.
When the air does not have a lot of moisture in it, your sweat evaporates faster. We all know that sweat is our body’s way of cooling us down, stabilizing our internal body temperature. Our physiology] is such that we can only withstand small increases or decreases in internal temperature; when the temperature becomes to high, we sweat in order to bring it down a little.
The problem with humidity is that when we sweat, it does not evaporate as fast as it does in ‘dry heat’, and because of this, our body temperature increases and it takes our internal mechanism longer to bring it back down.
Therefore, do not work out when it is humid, only when the air is dry. The strain placed on your body may cause severe damage.
Just another friendly word of warning from Cyberculosis, a.k.a. ‘That guy over there.’