Professor Peter Hayes of the University of Alberta (Canada) analysed the records of 628 first heart attack patients and found that those in rooms on the south side of a hospital's cardiac intensive care unit tended to fare much better than those treated on the north side. The study showed that 39% of patients on the north side (which was much darker, with less sunshine) failed to survive compared to 21% on the sunnier south side.

The effect was particularly noticeable in women patients, supporting other research which had suggested that lack of daylight affected women's mental health more significantly than men's.

Ed.- (i) In 1996, the same team showed that clinically depressed patients in sunny hospital rooms fared far better than those in dull rooms.

(ii) Alternatives in Health's editor, Adam Jackson, pointed out that organisations could combat the adverse effects of lack of sunshine (termed Seasonal Affective Disorder (SAD)) by installing full spectrum lighting. He recommended Outside-in (Cambridge) Ltd. as a supplier (Tel: 01954 211955).