summary: A new study shows that taking a three-minute resistance exercise break every 30 minutes at night can increase sleep time by an average of 27 minutes, without compromising sleep quality and potentially reducing the risk of cardiometabolic disease.
Participants performed simple exercises such as chair squats and calf raises. Further research is needed to confirm these results in real-world situations.
Key Facts:
- Sleep Extension: Exercise breaks increased sleep time by 27 minutes.
- No interruptions: The exercise did not affect sleep efficiency or cause nighttime awakenings.
- Health Effects: Increasing sleep duration may reduce the risk of cardiometabolic diseases.
sauce: BMJ
Nighttime resistance exercise “activity breaks” may improve sleep duration, suggests the results of a small controlled study published in an open access journal. BMJ Open Sport & Exercise Medicine.
Research suggests that taking a three-minute break every 30 minutes for four hours may be enough.
Current recommendations advise against vigorous exercise before bedtime because it can increase body temperature and heart rate, reducing sleep quality, according to the researchers.
Although post-meal exercise breaks may improve metabolism, it is unclear whether they have any effect on sleep, as poor sleep has been linked to an increased risk of cardiometabolic disorders such as coronary heart disease and type 2 diabetes, the researchers explain.
To explore this further, the researchers enrolled 30 non-smokers aged 18 to 40 years old, all of whom reported spending more than five hours sitting during the day and more than two hours sitting in the evening while at work.
To capture habitual physical activity and sleep patterns, participants wore an activity tracker on their non-dominant wrist for seven consecutive days and were asked to record periods when they did not wear the device, as well as their bedtime and wake-up times.
Participants were also asked to record physical activity they engaged in while not wearing the activity tracker, such as swimming or contact sports, as well as activities known to be inaccurately identified by trackers, such as stationary biking and yoga.
Each participant completed two 4-h sessions in a controlled laboratory environment, starting around 17:00–17:30 on the same day of the week, with a minimum of 6 days between sessions.
In one session, participants remained seated for four hours. In the other session, they performed three minutes of simple resistance exercise every 30 minutes for four hours. Afterwards, participants returned to their usual daily living environment.
During each activity break, participants performed three 20-second rounds of three exercises – chair squats, calf raises, and standing knee-raise leg extensions and hip extensions – while also playing a video recording of someone performing the same exercises.
Before the study, participants averaged 7 hours 47 minutes of sleep, 10 hours 31 minutes of sitting, and 4 hours 55 minutes of vigorous physical activity per day, according to activity tracker data.
Three in four people got the recommended seven hours of sleep, while the rest slept less (21%) or more than nine hours (4%).
Results based on 28 participants showed that after a break from activity, participants slept an average of 27 minutes longer compared to when they remained seated for an extended period of time.
The average sleep duration was 7 hours 12 minutes, compared to 6 hours 45 minutes after prolonged sitting. The times when participants tried to go to sleep were similar, but the average wake-up times differed: participants woke up at an average of 7:35 after the prolonged sitting intervention and at an average of 8:06 after the usual activity break.
Additionally, there were no significant differences in sleep efficiency (uninterrupted sleep) or number of nighttime awakenings between the two interventions, suggesting that the interruptions in activity did not interfere with subsequent sleep, the researchers said.
There were no statistically significant differences in 24-h activity patterns following each intervention, but compared with prolonged sitting, regular activity breaks reduced total physical activity time by 18 minutes, or less than 2% of total waking time.
The researchers acknowledged that their findings have various limitations, including that the study had a small number of participants and was conducted in a laboratory setting, which may not reflect real-life behavior.
The researchers therefore stress that further studies are needed in which more people are surveyed over a longer period of time in normal home environments.
But still, they state: “These results add to a growing body of evidence showing that, contrary to current sleep recommendations, evening exercise does not impair sleep quality.”
And the researchers point out: “Adults spend most of their time sedentary and consume nearly half of their daily energy intake in the evening, when insulin sensitivity is also reduced.”
The researchers suggest that extending sleep time through activity breaks may reduce the risk of cardiometabolic disease in the long term, especially for people who sleep less than the recommended total nightly sleep time.
The strength-training exercises used in the study were easy to do, required no equipment, and could be done while streaming content, which may make people more likely to stick to their routine, the researchers added.
However, they emphasize: “Existing research suggests that nighttime exercise may not have a negative effect on sleep; however, [it] It is unclear what effect this may have on sleep quality.”
About this exercise and sleep research news
author: BMJ Group Media Relations
sauce: BMJ
contact: BMJ Group Media Relations – BMJ
image: Image courtesy of Neuroscience News
Original Research: Open access.
“Regular nighttime activity breaks extend subsequent free-living sleep duration in healthy adults: a randomized crossover trial” by Jennifer T. Gale et al. BMJ Open Sport and Exercise Medicine
Abstract
Regular nighttime activity breaks extend subsequent free-living sleep duration in healthy adults: a randomized crossover trial
objective
To determine whether three minutes of regular resistance exercise over a four-hour period at night, compared with prolonged continuous sitting, affects subsequent sleep quantity and quality, sedentary time, and physical activity.
Method
In this randomized crossover trial, participants each completed two 4-h interventions beginning at approximately 5:00 pm: (1) extended sitting and (2) sitting with 3-minute bodyweight resistance exercise breaks every 30 minutes.
Upon completion, participants returned to their free-living environment. This paper reports secondary outcomes of sleep quality and quantity, physical activity, and sedentary time assessed using a wrist-worn ActiGraph GT3+ accelerometer combined with a sleep and wear time diary.
result
28 participants (20 women), age 25.6±5.6 years, BMI 29.5±6.7kg/m2 (mean ± SD) provided the data for this analysis.Compared with prolonged sitting, periodic activity breaks increased mean sleep duration and sleep time by 29.3 minutes (95% CI: 1.3 to 57.2, p=0.040) and 27.7 minutes (95% CI: 2.3 to 52.4, p=0.033), respectively, on the intervention night.
There were no significant effects on mean sleep efficiency (mean: 0.2%, 95% CI: -2.0 to 2.4, p = 0.857), awakenings after sleep onset (1.0 min, 95% CI: -9.6 to 11.7, p = 0.849), or number of awakenings (0.8, 95% CI: -1.8 to 3.3, p = 0.550). There were no significant differences in subsequent 24- and 48-h physical activity patterns.
Conclusion
An evening activity break with bodyweight resistance exercise may improve sleep duration and total sleep time without interfering with other aspects of sleep quality or subsequent 24-h physical activity. Future studies should investigate the longer-term effects of an evening activity break on sleep.
Clinical trial registration number
Australia New Zealand Clinical Trials Registry (ACTRN12621000250831).
