NEWS BRIEF: The calorie-burning perk of “springing forward”

I devoted a decent amount of space last month discussing the dangers of daylight savings. So now let’s talk about one of the season’s many perks—the extra hour of daylight we get after a long, dark winter.

You could spend this extra hour of daylight doing any number of things—whether it’s reading on a park bench or digging in your garden. But if I may make a suggestion, I hope you’ll consider using it to exercise. And here’s why…

As part of a recent study, researchers isolated seven people in a lab setting with no windows, clocks, phones, or internet for three weeks. They had no idea what time of day it was—and that was precisely the point.

Each subject was assigned a bedtime and a wake time, with 4-hour adjustments made throughout the length of the study. These adjustments ensured subjects’ bodies were never able to settle into a rigid pattern, allowing researchers to observe natural patterns as they emerged.

And get this: Results showed that metabolic rates differed significantly throughout the day—operating slowest late into the subjects’ biological night, and fastest during their biological afternoon and evening.

Further, the same activities burned significantly more calories in the late afternoon and early evening hours than they did during any other time of the day.

The explanation for this, as you might have guessed, boils down to circadian rhythms—a topic I explored in detail back in the March 2018 issue (“The deadly cost of a broken ‘body clock’”). Every person has his or her own internal “body clock” that they follow—including preferred times to eat, sleep, and move.

Regular exercise is one of the most effective ways to regulate this clock. Which is why it’s always a good time to exercise—whether you do it first thing in the morning or right before you go to bed.

But as this research clearly shows, late afternoon workouts deliver some pretty serious bang for your buck. And I really can’t think of a better way to spend these beautiful spring evenings than with a walk, run, or bike ride in the sunshine.

Source:

“Human Resting Energy Expenditure Varies with Circadian Phase.” Curr Biol. 2018 Nov 19;28(22):3685-3690.e3.