From Longman Dictionary of Contemporary Englishsunstrokesun‧stroke /ˈsʌnstrəʊk $ -stroʊk/ noun [uncountable] MIfever, weakness etc caused by being outside in the sun for too long
Examples from the Corpus
sunstroke• Thirty-five laps into the race he was beginning to feel faint from a combination of thirst and sunstroke.• Midday temperatures can be high and the major causes of chick mortality are sunstroke and overheating.• It may indeed have been caused by sunstroke or by an epileptic seizure.• She was suffering from sunstroke and she died within a short time.• She hoped she would not get sunstroke.• By the end of the day they were both suffering from a mild bout of sunstroke and were also feeling a little seasick.• She decided to rest, having treated enough cases of sunstroke to know very well how easily it was caught.• They had both loved poor little Mary Porter who died of sunstroke. 