Heat can beat the heart.  Play it safe in hot, humid weather--it can overheat the heart.
D001831:Body Temperature; D001833:Body Temperature Regulation / Q000502:physiology*; D002320:Cardiovascular Physiological Phenomena; D003681:Dehydration / Q000517:prevention & control; D007722:Health Knowledge, Attitudes, Practice; D006321:Heart / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D013546:Sweating