Less Phone or More Exercise? What a 503-Person Experiment Found

If your phone is taking too much of your day, is the fix to use it less, or to fill the time with something better, like exercise? A team at Ruhr University Bochum in Germany tested both, alone and together, in a randomized experiment with 503 adults, and followed them for three months afterward.

What the researchers did

The study, by Precht and colleagues, appeared in the Journal of Public Health (online in 2023, in print in 2024). Between April 2021 and May 2022 it enrolled adults who used a smartphone at least an hour a day, could exercise for 30 minutes a day, and usually did no more than an hour of physical activity a day. They were recruited through university mailing lists, social media, television and radio. Most were women (80.5%), the average age was 29, and the oldest was 79.

A simple randomization put each person in one of four groups for 14 days:

• Less phone: use the smartphone 60 minutes less each day, counting every kind of use.
• More exercise: add 30 minutes of physical activity a day, such as jogging, cycling, swimming, weight training or fast walking.
• Both: the hour less and the 30 minutes more.
• Control: carry on as usual.

The three active groups kept a daily diary of whether they had followed their task. Most did, on at least 9 of the 14 days: 85% in the less phone group, 93% in the exercise group and 83% in the combined group. People who didn't keep to it stayed in the analysis, so the results are, if anything, conservative.

Everyone answered online surveys before the two weeks, halfway, at the end, and one and three months later. They reported their daily phone time and weekly exercise, and filled in standard scales for problematic smartphone use, positive mental health (well-being), depression and anxiety.

What they found

All three changes increased weekly exercise and reduced symptoms of problematic phone use, depression and anxiety, though not on the same timetable.

The differences showed up over time. Cutting phone use, alone or together with exercise, produced effects that held up longer than exercise alone:

• Phone time stayed down. The two groups that cut their use were still using their phones less one and three months later. At three months, the less phone group used its phone less than every other group.
• Well-being rose later. In both phone-cutting groups, positive mental health was higher at the one and three month follow-ups than at the start.
• Problematic use kept falling. In the less phone group, it didn't change during the two weeks themselves, then kept dropping over the next three months.
• Ahead of the controls. At three months, the less phone group had fewer symptoms of depression and anxiety than the control group.

The exercise-only group's gains were clearest around the end of the two weeks. The authors describe most of the effects as small to medium, and conclude that cutting phone time, combined with more physical activity, could be a cheap way to prevent problematic phone use and support mental health.

What the study can't tell you

Phone time and exercise were self-reported, not logged, so some of the changes may reflect what people believed they did. The sample was mostly young, female and German, and all participants were described as white, which limits how far the results reach.

The doses were the same for everyone, so an hour less may have meant nearly giving up the phone for some people and only a modest trim for heavy users. The authors suggest that tailoring the cut to each person, and finding the right amount of phone use, needs more research.

What it means for your phone

• Cut first, then add. The phone cut is the part whose benefits lasted. Exercise helped, and it's a good use of the hour you get back.
• Give it time. In the less phone group, problematic use kept falling for months after the two weeks ended.
• Make the hour hold. Our 30-day plan to stop phone addiction uses both halves of this study: an hour's cut in week two and movement in week three.

Unrotten can keep that hour for you: choose the apps that eat your time and give them a daily limit with Less scrolling, and its MindBattery shows the difference, draining while you use those apps and recharging with sleep, movement and time away from them.