Recent research suggests that the allocation of time to sleep, physical activity, and sedentary behavior over a 24-hour period influences long-term health, and that attaining adequate levels of both sleep and physical activity is essential for healthy aging.
A recent study published in Communications Medicine found that only 12.9% of individuals simultaneously attain the recommended 8,000 daily steps and 7-9 hours of sleep.
Moreover, the study showed that a lack of adequate sleep had a negative impact on physical activity the following day. These results suggest that obtaining adequate sleep could help improve physical activity levels.
Why sleep is as important as physical activity
Studies have shown that both adequate sleep and physical activity are essential for maintaining optimal mental and physical health.
Lack of adequate physical activity and insufficient sleep have been independently shown to be associated with an increased risk of depression, obesity, diabetes, cardiovascular conditions, inflammation, and all-cause mortality.
Sleep and physical activity influence each other over a 24-hour period. Studies have shown that increased physical activity is associated with better sleep quality, while insufficient sleep the night before can lead to lower physical activity due to fatigue and hormonal disruptions.
In addition, the combined pattern of time spent in sleeping, sedentary behavior, and physical activity together over a 24-hour period influences health outcomes.
For instance, the combination of a lack of adequate sleep and low physical activity is associated with increased risk of mortality. Thus, it is vital to simultaneously assess the time allocated to sleep and physical activity over a 24-hour period.
Studies have shown that the number of daily steps can serve as a measure of physical activity, with higher daily step counts linked to lower risk of chronic conditions and mortality.
These studies suggest that achieving a minimum of 8,000 steps daily can help reduce cardiovascular risk and lower overall mortality risk.
In individuals aged over 60 years, evidence suggests a minimum of 6,000 steps could be beneficial for maintaining optimal health, with the benefits plateauing with a further increase in stepping activity.
At the same time, the National Sleep Foundation recommends 7 to 9 hours of sleep for adults aged 18 to 64, and 7 to 8 hours for individuals aged 65 and older.
Previous studies examining the interrelationship between sleep and exercise have been limited by small samples restricted to a single geographical region, reliance on self-reported sleep data, and short follow-up durations.
In the present study, the researchers used a large, multinational sample to evaluate the proportion of individuals who simultaneously attained the recommended hours of sleep and physical activity.
They also examined the interrelationship between sleep and daily step count over a 24-hour period.
To get your daily steps in, you first need proper sleep
The present study used health monitoring data collected over 3.5 years from 70,963 individuals residing in 244 geographical regions.
These individuals were users of consumer health tracking devices in the form of an under-mattress sleep sensor and a fitness tracker.
Based on data collected by the sleep sensor, the researchers calculated sleep duration, sleep onset, and sleep efficiency, a measure of time spent sleeping while in bed.
The researchers found that only 12.9% of the participants obtained 7-9 hours of sleep and also achieved at least 8,000 daily steps.
In contrast, 16.5% of participants simultaneously averaged less than 7 hours of sleep and 5,000 steps daily, the upper threshold for sedentary behavior. Furthermore, about 64% of individuals failed to achieve a combination of 7-9 hours of sleep and at least 5,000 daily steps.
The researchers then examined how sleep metrics influenced daily step counts on the following day, and vice versa. The relationship between sleep duration and daily steps was characterized by an inverted U-shaped curve, with less than 6 hours and more than 9 hours of sleep being associated with a lower number of steps on the subsequent day.
Around 6-7 hours of sleep the night before was associated with the highest number of steps on the subsequent day.
Latency to sleep had an inverse relationship with the number of daily steps, with the number of steps decreasing as the duration to fall asleep increased.
In contrast, sleep efficiency, the proportion of time in bed spent sleeping, showed a positive correlation with the number of steps on the following day.
Higher daily step count was associated with a lower latency to sleep and a greater proportion of time spent sleeping while in bed. Interestingly, the impact of daily steps on these sleep metrics was small.
Best to think of sleep and exercise as a power couple
Although the current study found a minimal impact of daily step count on sleep metrics, other studies suggest that physical activity, especially of moderate-to-vigorous intensity, influences sleep quality.
One of the reasons for the disparity between the aforementioned results and those of the present study could be that the fitness trackers used in the study did not record all forms of physical activity or other related parameters.
Fitton explained that “the step count metric used does not capture other forms of physical activity (e.g., swimming), and we were unable to assess the intensity and timing of the activity, which will be important to consider moving forward.”
“Our sample consisted of users of consumer-available health monitoring devices and, therefore, are likely to be of higher socio-economic status and/or health-conscious individuals. It is not a representative global sample,” he added.
The researchers note that the bidirectional relationship between physical activity and sleep underscores the need for public health interventions that could help individuals achieve both 7-9 hours of sleep and increase physical activity simultaneously, instead of targeting them individually.
