I do not sweat, if i get overheated i start to feel faint and flusterd and heart rate gets dangerously high. makes it hard to work out.

Anhydrosis : If you really do not sweat you could have one of several inherited defects in the pathway, or take a medicine which stops sweating or you might be dehydrated. A sweat test could make the diagnosis. You could become quickly overheated even up to the level of a heat stroke. Avoid activities which would normally require sweating to cool the body.