Dangers Posed by Dehydration and Overheating
Some of these deaths are related to overheating. MDMA slightly raises body temperature. This is potentially lethal in hot environments where there is vigorous dancing and the lack of adequate fluid replacement. Many of these tragic deaths are preventable with simple harm reduction techniques such as having free water available and rooms where people can rest and relax.
C.M. Milroy; J.C. Clark; A.R.W. Forrest, Pathology of deaths associated with "ecstasy" and "eve" misuse, Journal of Clinical Pathology Vol 49 (1996) 149-153.