Tuesday, 16 April, 2024
HomeCardiologySleeping beats sitting when it comes to heart health: UK study

Sleeping beats sitting when it comes to heart health: UK study

A cross-sectional study investigating the impact of movement behaviour on cardiometabolic health suggests that replacing 30 minutes of daily sitting with equal time standing or even sleeping could improve obesity markers like body weight and waist circumference.

While higher-intensity activity might confer benefits sooner, said the scientists, adding more light activity or more standing, or even going to bed earlier, could improve heart health measures over time.

“Our study highlights that replacing sedentary behaviour with any other behaviour can be beneficial,” said study author Joanna Blodgett, PhD, a researcher at University College London’s Institute of Sport, Exercise and Health, and department of targeted intervention.

The study builds on a large and growing body of evidence that movement behaviours impact cardiometabolic health, reports Medscape. Increasing physical activity to 150 minutes a week has been shown to reduce the risk for cardiovascular disease by 17% and type 2 diabetes by 26%.

Other studies suggest that even modest increases in physical activity can be beneficial. A prospective study published last month found that even short activity bouts of a few minutes a day may lower risks for heart attack, stroke and early death.

In this latest study, published in the European Heart Journal, researchers analysed data from six studies and more than 15 000 participants, ranking behaviours according to their association with heart health.

Moderate-to-vigorous activity was linked to the greatest benefit, followed by light activity, standing, sleeping, and finally – dead last on the list – sitting.

A thigh-worn device tracked participants’ activity throughout the day, and six measures gauged heart health: body mass index, waist circumference, HDL cholesterol, total-cholesterol-to-HDL ratio, triglycerides, and glycated haemoglobin (HbA1c).

Researchers modelled what would happen if people swopped various amounts of one activity for another every day for a week.

Replacing just four to 13 minutes of sitting with moderate-to-vigorous activity (movement that gets you to reach 65%-75% of your maximum heart rate) improved heart health markers.

The cardiovascular demands of regular intense activity like running, cycling, dancing, or playing sports – even in small bouts – strengthen the heart and improve blood flow throughout the body, Blodgett said.

“This can lower cholesterol, blood pressure, and resting heart rate.”

Even if adding moderate-to-vigorous activity is not an option, the findings suggest that people can still see benefits by replacing sitting with virtually any other activity – walking, standing, even sleeping.

Limitations

Because the study was observational, results can’t be used to infer causality.

“We cannot directly lean on the study results to guide prescriptions for particular exercise or lifestyle changes,” said Matthew Tomey, MD, a cardiologist with the Mount Sinai Health System in New York City, who was not involved with the study. An interventional trial would be needed to confirm the findings, he said.

The finding that sleep was better for participants than sitting is a good example. The benefits of replacing sitting with sleep were “clear” for adiposity measures like BMI and waist circumference, but negligible for blood markers such as cholesterol, triglycerides, and blood glucose, Blodgett said.

One explanation: “The negative impact of sitting on these obesity measures is possibly due to related unhealthy behaviours, like snacking, rather than the physiological benefits of sleep itself,” Blodgett said.

What’s more, study participants were relatively young, healthy, and active. The average age was 54, and they averaged nearly eight hours of sleep, 10 hours of sitting, three hours of standing, 1.5 hours of light activity, and more than an hour of moderate-to-vigorous activity per day.

So it’s difficult to draw conclusions about patients who don’t fit those metrics.

Impact on patient care

That said, the results could help tailor recommendations for patients, Blodgett said.

If a patient is struggling to exercise or is unable to exercise because of health or ability restrictions, you could help them find ways to add a lighter activity to their day, like taking the stairs or walking briskly to catch the bus.

Even swopping a regular desk for a standing one, or going to bed 30 minutes earlier, could be a more practical and effective suggestion.

More than that: the research could be used to educate patients on the power of small changes.

It shows that shifting daily habits even in small ways can make a difference, and people who are the least active stand to benefit the most.

You can also remind patients that moderate or vigorous activity doesn’t need to happen at the gym. It could be lawn work, taking a walk, or moving heavy boxes. In fact, many activities can be “moderate” or even “vigorous”, depending on the effort put into them.

Share this rule of thumb: “An activity is classified as moderate intensity if you can talk but not sing while doing it, and an activity is generally considered vigorous intensity if you can’t say more than a few words without stopping to breathe,” Blodgett said.

The study also has implications for the potential of wearable activity trackers to monitor progress. Combining objective activity data with results from studies like this, and longer prospective studies, could help inform more helpful advice.

“Ultimately, this research helps move us closer to more personalised guidance of how changing behavioirs can improve your health,” Blodgett said.

Study details

Device-measured physical activity and cardiometabolic health: the Prospective Physical Activity, Sitting, and Sleep (ProPASS) consortium

Joanna Blodgett, Matthew Ahmadi, Lauren Shera, et al.

Published in European Heart Journal on 10 November 2023.

Abstract

Background and Aims
Physical inactivity, sedentary behaviour (SB), and inadequate sleep are key behavioural risk factors of cardiometabolic diseases. Each behaviour is mainly considered in isolation, despite clear behavioural and biological interdependencies. The aim of this study was to investigate associations of five-part movement compositions with adiposity and cardiometabolic biomarkers.

Methods
Cross-sectional data from six studies (n = 15 253 participants; five countries) from the Prospective Physical Activity, Sitting and Sleep consortium were analysed. Device-measured time spent in sleep, SB, standing, light-intensity physical activity (LIPA), and moderate-vigorous physical activity (MVPA) made up the composition. Outcomes included body mass index (BMI), waist circumference, HDL cholesterol, total: HDL cholesterol ratio, triglycerides, and glycated haemoglobin (HbA1c). Compositional linear regression examined associations between compositions and outcomes, including modelling time reallocation between behaviours.

Results
The average daily composition of the sample (age: 53.7 ± 9.7 years; 54.7% female) was 7.7 h sleeping, 10.4 h sedentary, 3.1 h standing, 1.5 h LIPA, and 1.3 h MVPA. A greater MVPA proportion and smaller SB proportion were associated with better outcomes. Reallocating time from SB, standing, LIPA, or sleep into MVPA resulted in better scores across all outcomes. For example, replacing 30 min of SB, sleep, standing, or LIPA with MVPA was associated with −0.63 (95% confidence interval −0.48, −0.79), −0.43 (−0.25, −0.59), −0.40 (−0.25, −0.56), and −0.15 (0.05, −0.34) kg/m2 lower BMI, respectively. Greater relative standing time was beneficial, whereas sleep had a detrimental association when replacing LIPA/MVPA and positive association when replacing SB. The minimal displacement of any behaviour into MVPA for improved cardiometabolic health ranged from 3.8 (HbA1c) to 12.7 (triglycerides) min/day.

Conclusions
Compositional data analyses revealed a distinct hierarchy of behaviours. Moderate-vigorous physical activity demonstrated the strongest, most time-efficient protective associations with cardiometabolic outcomes. Theoretical benefits from reallocating SB into sleep, standing, or LIPA required substantial changes in daily activity.

 

European Heart Journal article – Device-measured physical activity and cardiometabolic health: the Prospective Physical Activity, Sitting, and Sleep (ProPASS) consortium (Creative Commons Licence)

 

Medscape article – Sleeping Beats Sitting? What a New Study Means for Your Patients (Open access)

 

See more from MedicalBrief archives:

 

Sitting eight hours a day linked to increased health risks – Latin American study

 

Sitting time cuts lifetime

 

Sitting for hours can increase CVD risk, hasten death – cohort study

 

 

 

 

 

 

 

 

 

 

 

 

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