Why Britons Get Their Best Sleep On Tuesday Nights

Woman yawns
A woman yawns while walking down Oxford Street, London, December 19, 2009. Dan Kitwood/Getty

Minds may be buzzing with news of Brexit and Euro 2016 this week, but Britons sleep best on Tuesday nights, according to researchers.

Analysis of heart rate data collected from almost 5,000 British men and women has showed that while Tuesday night's sleep isn't the longest, it is the most restorative.

According to researchers at analytics company Firstbeat, a Tuesday night's slumber is less likely to be interrupted by alcohol, rich food or other excesses that are more common later in the week.

The find comes from a study of more than a billion readings, taken over the last decade and collected by heart monitors worn by 4,866 men and women around the clock for three consecutive days. In one of the biggest study of its kind, the volunteers also provided information on their sleep times and how stressed they felt.

As might be expected, the men and women slept longest at the weekend. But this sleep was of lower quality, with substantially less time spent in "recovery state" than earlier in the week. This sort of sleep is said to be particularly restorative and is characterized by a drop in blood pressure and stress hormones and a change in way the heart beats. While a stressed heart beats at regular intervals, a relaxed one alternates between fast and slow bursts.

Just 48 percent of Saturday night's sleep, and 48.7 percent on Fridays, revitalizes the body and brain—compared to a healing high of 55.1 percent on Tuesdays. The researchers said boozy weekends are likely to be to blame for the end of week dip.

Monday nights are also restful, with 54.6 percent of sleep deemed to be rejuvenating, the data from showed.

Simon Shepard, of Optima-Life, the U.K. distributor for the 50p-sized heart monitors, said: "There is a big difference between rest and restoration. People rest for a lot longer during the weekend but perhaps they are out partying and letting their hair down and their bodies don't physiologically recover.

"On Mondays and Tuesdays, your energy levels may still be high after the weekend. And while you may still be sociable, you may be sociable in a different way, going to a book group rather than down the pub."

The data also revealed that women sleep longer—but men sleep more soundly. The typical female studied got 7 hours and 34 minutes of sleep a night—11 minutes more than the man in her life. But just 49 per cent of female sleep is spent in recovery mode, compared to 54.5 per cent for males.