Fitness band data show workouts peak on Mondays

SAN FRANCISCO — Oh, optimism.

After falling off diets and exercise regimes all weekend, people start the new week with a flourish of exercise, running, walking or hitting the gym. And then their habits gradually deteriorate as the week progresses, a new data analysis shows.

Jawbone, the maker of computer-connected fitness bands, collected data from a sample of more than 100,000 of its U.S. users in a 12-month period ending in August. Users of the Jawbone UP band automatically log sleep, inactivity and walking just by wearing the band. They also can record their type of workouts — say taking a yoga class or playing basketball — plus food intake into a connected app.

The sheer number of users allows for very big data sets, which the company's vice president of data, Monica Rogati, said should allow it to draw some conclusions about exercise habits that smaller studies can't.

What Jawbone found in terms of exercising isn't exactly shocking, but it puts some numbers on what many might suspect from their own habits. Similar to the surge of gym memberships sold during the start of the year, overall workouts peak on Monday, are fairly steady Tuesday and Wednesday, and then fall apart.

If the gym seems more crowded Monday, there's your answer. The greatest percentage of cross-training, weight-lifting and stationary bike workouts happen on Mondays, for both men and women, gradually ebbing as the week goes on. Gym workouts bottom on the weekend, when there's an uptick in outdoors activity. Friday is the lightest day for exercise overall.

"There's a new week resolution effect," said Rogati. "People are pumped about their workout, going to the gym. As it goes by, people slowly drop the routine."

PEAK BACON

The new week resolution pattern spilled over into eating patterns, too. Jawbone data found that the greatest percentage of kale and quinoa was eaten on Monday, while the most bacon was consumed on Sunday.

Jawbone, naturally, has a solution for these habits. If the app starts to record this pattern, it may nudge the user to shift that routine, say by suggesting a short walk on Friday.

"For all of these studies, we have found that willpower is a limited resource," says Rogati.

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