This One Simple Habit May Help You Sleep Better, According to a New Study

There is no question how important it is to get plenty of quality sleep and physical activity. Sleep supports a strong immune system and healthier skin. It can also reduce blood pressure and help maintain a healthy weight. And like sleep, exercise has been linked with a plethora of benefits, from improving the symptoms of depression and anxiety to supporting a strong heart, lungs, muscles and bones. 

Exercise has also been shown to help you sleep better. According to the 2018 Physical Activity Guidelines for Americans, engaging in regular physical activity may help improve sleep quality, promote deeper sleep, reduce daytime sleepiness and reduce the need for a sleep aid. 

Through the years, various recommendations have been tossed around regarding the best time of day to exercise—whether for weight loss, blood sugar management or better sleep (spoiler alert—the best time is the time of day you’ll do it consistently!). 

There is a general consensus that you shouldn’t exercise too close to bedtime, as it can disrupt sleep. But a new study published in BMJ Open Sport & Exercise Medicine on July 16, 2024, challenges this idea. Let’s see what these researchers found.

How Was This Study Conducted & What Does It Suggest?

Researchers recruited 28 individuals from New Zealand. They were mostly women (71%), ages 19 to 39 with a wide range of BMIs. There were certain parameters the participants had to meet to qualify for the study. This included things like being a nonsmoker, not being on medication or supplements that impacted glucose or triglycerides (i.e., diabetes medication or cholesterol medication) and no intolerances or allergies to gluten or dairy. A normal day for participants had to include more than five hours of sitting time during the day and at least two hours of sitting in the evening.

Participants were required to attend an introductory session at which study protocols were discussed. During this session, they watched a video demonstrating the exercises they would perform during the study period. 

Each participant was also fit for an accelerometer—a fancy pedometer that picks up most movement, not just steps. The accelerometer was worn on their nondominant wrist for seven consecutive days, 24 hours daily, to record physical activity and sleep time. These seven days were to establish each participant’s baseline activity and sleep habits to compare them to the intervention they would be participating in for the study.

They also received a diary to record activities that the accelerometer isn’t so great at picking up, like bicycling and yoga, and those for which they needed to remove it, like if they were swimming or playing a contact sport. Participants also used the diary to record what time they went to bed, what time they attempted to fall asleep and what time(s) they woke up (including waking up during the night).

For the study, researchers wanted to know if breaking up sitting time in the evening with resistance exercises would influence sleep quality and quantity. Specifically, they wanted to know if performing regular three-minute bouts of resistance exercise every 30 minutes, spread out over four hours, would impact sleep, compared to sitting for those four hours. So sitting for four hours was one intervention and taking regular activity breaks was the other intervention.

Once baselines were established, participants were randomly placed into one of two groups. One group did the activity breaks intervention first, then on another night at least six days later they did the sitting intervention. The other group did the sitting intervention first and then the regular activity breaks intervention, also with at least six days between interventions.

To try to reduce certain influences on the results, on intervention days participants were provided the same breakfast, morning tea, lunch and snacks, all of which were to be consumed by 2 p.m. Participants were also instructed to avoid all moderate-intensity to vigorous-intensity activities during the 24 hours prior to the interventions. Interventions were done on either Tuesdays or Thursdays to ensure the following day was a typical weekday instead of a weekend.

Participants also wore the accelerometer starting on the morning of the experiments until 48 hours after the interventions. This was to record activity levels following the interventions, as well as to record sleep and wake times. Remember, these researchers wanted to know if the interventions influenced sleep. 

The four-hour interventions—activity breaks and sitting—were performed in a lab setting to ensure protocol compliance. The rest of the interventions, including sleeping, were done in what researchers refer to as “free-living conditions”—which means they slept at home.

For the sitting intervention, participants sat for four hours in the evening, starting around 5 p.m. During the four hours, they could watch television, read or work on a portable device. They were allowed to get up only to use the bathroom.

The activity intervention was similar to the sitting intervention, except that participants performed three minutes of simple resistance exercises every 30 minutes. The exercises included chair squats, calf raises and standing knee raises with straight leg hip extensions (rear leg lifts). Each exercise was performed for 20 seconds for three rounds, to total three minutes. 

Once all the data was collected and several statistical analyses were run, the results were in. On the night participants took regular activity breaks, they slept, on average, 29.3 more minutes compared to the night after they sat for four hours straight. 

How Does This Apply to Real Life? 

You might be thinking that 29 more minutes a night isn’t a big deal. But according to these researchers, previous studies have suggested that an additional 30 minutes a night of sleep can have positive effects on health. This is especially true if you typically get fewer than seven hours of quality sleep a night, since the general recommendation is seven to nine hours of sleep per night for adults, according to the Centers for Disease Control and Prevention.

It’s also important to keep in mind that health habits are cumulative. It all adds up. So 30 more minutes a night adds up to 3.5 more hours of sleep a week—which adds up to 182 more hours of sleep a year. 

This applies to other health habits, too—like exercise. This study emphasizes how short bouts of exercise in the evening can help improve sleep. But you’re also strengthening your muscles, increasing your heart rate a bit, and adding to your movement for the day. 

So while these study participants exercised for just three minutes at a time, it was every 30 minutes. That’s six minutes an hour for four hours, which adds up to 24 minutes. If you did that every day, that’s 168 minutes of movement per week. Current guidelines suggest 150 minutes of moderate-intensity activity per week. Depending on your fitness level, the three exercises participants performed for the study would fall into the light-to-moderate category of intensity.

These examples are mostly to prove a point, since you want to do a variety of exercises to ensure you’re working different muscle groups, increasing your heart rate, stretching, etc.—just like you want to eat a variety of foods to ensure you’re getting a wide range of nutrients. The point here is that exercise can be broken up, no matter what time of day it is, and it can be done in the evening if that’s the only time you have to do it. 

These researchers also point out that the exercises they chose for the study are simple and require no equipment. This removes a common mindset obstacle many people run into, thinking they must join a gym or invest in a lot of pricey equipment to become fit—when in fact, all you really need to get started is your body. 

There is still a question as to whether high-intensity exercise too close to bedtime will affect sleep. In this case, since research is mixed, we recommend seeing what works best for you. For example, if you’re doing a HIIT workout in the late evening and find it difficult to fall asleep, then try moving your high-intensity workout to earlier in the day and stick to more moderate activity in the evening to see if it helps you get better sleep. 

The Bottom Line

This study suggests that light- to moderate-intensity resistance exercises, done to break up sitting time in the evening, may increase that night’s sleep time by almost 30 minutes. Too much sitting time in general has been shown to have some detrimental effects on health, including a higher risk of premature death, back and joint issues, headaches and a decline in mental health. It’s a good idea to break up your sitting time throughout the day with activity breaks to improve overall health, increase the amount of movement you’re getting each day—and hopefully, help you sleep better at night.