A 25-year series of rigorous sleep studies proves men and women really are marching to wildly different drummers.
The Harvard Medical School study found fully 35 per cent of women live with a circadian rhythm (the 24-hour waking and sleeping cycle) of less than 24 hours.
Men typically have circadian rhythms of 24 hours plus a bit more.
This helps explain why women wake up earlier, tend to prefer morning activities and adapt better to jet lag when travelling east, Dr. Jeanne Duffy told the Star on Thursday.
She stressed the study quantified averages. Duffy herself is a night owl and figures her own circadian rhythm is a slightly-more-than-24-hour one.
The “average” difference between men and women is six minutes, but played out in real life it means “women are waking a half an hour or an hour and a half earlier than men.”
The study also gives science better means to understand the prevalence of insomnia among women, Duffy said.