Skip exercise? Just sitting less can further improve your metabolic health

Skip exercise? Just sitting less can further improve your metabolic health

New research shows that reducing sitting time in older adults significantly reduces the risk of metabolic syndrome - even among those who don't meet exercise guidelines or follow perfect diets.

Study: Associations between time spent in sedentary behaviors and risk of metabolic syndrome in physically active and inactive European older adults.

A study published inThe Journal of Nutrition, Health and Aginghighlights the importance of being physically active and limiting sedentary behaviors for improving metabolic health in physically active or inactive older adults.

background

Physical activity is an important lifestyle factor that greatly influences cardiovascular health. Current global guidelines recommend more than 150 minutes of moderate to vigorous physical activity per week and limited sedentary behavior for older adults to improve metabolic health and reduce metabolic risk.

Metabolic syndrome refers to a group of metabolic disorders, including insulin resistance, abdominal obesity, dyslipidemia, and hypertension, that collectively increase the risk of developing cardiovascular disease and type 2 diabetes, particularly in older adults.

Waist circumference, blood pressure and insulin resistance markers were noticeably better in people who spent the least amount of time sitting.

Older adults spend most of their time in sedentary activities. This sedentary lifestyle combined with reduced physical activity increases their risk of developing cardiometabolic abnormalities.

Existing evidence links excessive time spent in sedentary behaviors with an increased risk of morbidity and mortality. However, it remains uncertain whether sedentary behaviors independently contribute to metabolic risk or whether their negative effects can be attenuated by regular physical activity according to current guidelines.

The current study aimed to gain deeper insight into the influence of sedentary behaviors on metabolic risk in physically active and inactive older adults, focusing on a validated continuous metabolic syndrome risk score and considering their adherence to healthy dietary behavior commitments.

Study design

The current study used baseline data from the nu-Alter Study (the Northwestern University Altern Research Registry), which was a randomized controlled trial examining the effects of a healthy diet on biomarkers of inflammation in older European adults.

This study specifically analyzed Nu-Age baseline data on physical activity behaviors and metabolic risk factors in 871 community-dwelling older adults (age range: 65–79 years) from four European countries.

Participants' physical activity and time spent in sedentary behaviors were assessed for a week using accelerometers they wore during waking hours. The percentage of daily time spent in sedentary behaviors were categorized based on mathematically derived tertiles (one-third of total data) of sedentary behaviors (low, medium, and high tertiles).

Five metabolic risk factors were analyzed and used to create a continuous metabolic syndrome risk score (CMSY). Additionally, participants' healthy eating habits were assessed using food records.

Study results

The study reported that participants spent, on average, 60%, 37%, and 3% of their waking hours in sedentary behaviors, physical activity, and moderate to mild physical activity.

Participants with the least amount of time spent in sedentary behaviors (low tertile) had twice the time in moderate to large range of physical activities compared to those with the highest amount of time spent in sedentary behaviors (high tertile).

Approximately 50% of the study population were classified as physically active and performed at least 150 minutes of moderate to vigorous physical activity per week. The majority of physically active participants were in the low sedentary behavior tertile.

Risk of metabolic syndrome

The researchers found that sitting for more than 8.3 hours a day marked a clear point at which metabolic risk began to climb, even for those who were physically active.

The study found a significantly low risk of metabolic syndrome, measured using the continuous metabolic syndrome risk mode, among physically active and inactive participants who spent shorter periods of time in sedentary behaviors (low tertiles) compared to those who spent moderate and longer periods of time in sedentary behaviors (medium and high tertiles) subject to eating.

In contrast, no significant difference in metabolic syndrome risk was observed between tertiles of moderate and high sedentary behavior in active or inactive participants. This finding suggests a potential threshold effect where risk increases particularly above 8.3 hours per day of sedentary time.

Further comparison between the active and inactive groups revealed that physically active participants had a significantly low risk of metabolic syndrome across all sedentary behavioral tertiles.

This finding shows that 150 minutes of moderate to vigorous physical activity per week can significantly improve metabolic health in older adults, even if they spend extended periods of time in sedentary behaviors. Importantly, the beneficial effect of physical activity remained significant after adjusting for total MVPA time, suggesting that adherence to physical activity guidelines provides benefits even in highly active individuals.

Investigate significance

The study finds that the less time spent in sedentary behaviors, the lower the risk of metabolic syndrome in older adults, regardless of their physical activity status and healthy eating habits.

In particular, the study highlights that the lowest risk of metabolic syndrome is associated with physical activity behavior, characterized by shorter time spent in sedentary behavior combined with higher adherence to current guidelines for moderate to vigorous physical activity.

The results were across four European countries, strengthening the case that less is helpful, regardless of local diets or health systems.

The study also finds that physically inactive participants who spend less time in sedentary behavior can achieve better metabolic health despite little moderate to high physical activity. Because less time in sedentary behavior primarily translates into more time in light-intensity physical activity, this finding suggests that light-intensity physical activity—even below moderate intensity—may provide meaningful metabolic health benefits. This is particularly encouraging for older adults who may find it difficult to achieve moderate to moderate physical activity goals.

The study also showed that sedentary behavior has an independent association with metabolic risk - even when they take physical activity and diet into account - the need to manage sedentary time as a separate behavioral risk factor.

The study did not include older adults with frailty, dementia, or severe heart disease, which may limit the generalizability of the results to healthier, community-dwelling, community-dwelling populations. Furthermore, due to the cross-sectional design, the study was unable to determine the causality of observed associations.

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