Nursing home residents are one of the most at-risk populations for heatstroke deaths, a new European study finds.

Heatstroke also appears to be the most lethal for people who take blood pressure-lowering medication, according to the study published in the Archives of Internal Medicine.

French researchers studied survival rates and outcomes of heatstroke patients hospitalized during a 2003 heat wave in Europe. Of the patients in the study who died, at least half came from a nursing home facility. More than two-thirds were taking medication to lower their blood pressure.