The causes of heat stress include wearing heavy clothing, physical work or exercise, hot weather and high humidity.

VOA: special.2011.08.09

Dr Hallett is building on Nakaya's work to look at how such things as humidity affect the process.

ECONOMIST: Atmospheric science: Fake flakes | The

The Italian team have struggled in the high temperatures and humidity there in the last two seasons, but work by their tyre supplier Bridgestone on solving that problem has paid off.

BBC: Schumacher crushes rivals