This latest research at Swansea University's College of Engineering follows an initial study into theeffects that a normal pregnancy has on women's cardiovascular function.
But he said the detrimental effect on cognition could be due to be attributable to poor heart and lung function affecting the brain, or directly harmful effects of smoking on brain - as well as lung - tissue.
In the other studies, there was no evidence of adverse effectson kidney and liver function, no reports of light-headedness or loss of consciousness, no evidence of fluid or electrolyte loss that might contribute to heat stroke.