TOPLINE

A Finnish observational study of young and early midlife adults showed that those who got low-to-moderate (rather than vigorous) leisure-time exercise and sat for 3 or more hours a day outside of work were more likely to gain 10% or more of their body weight over 5 years. 

METHODOLOGY

• Exercise is known to help young adults maintain their weight, but few studies have looked at how exercise and sedentary behavior together affect large weight gains.
• Researchers drew on a 2017 survey of City of Helsinki employees aged 19 to 39 years and a 2022 follow-up to examine how leisure-time physical activity and leisure-time sitting, alone and combined, relate to major weight gain over 5 years; they analyzed data from 2606 adults (79.5% women) who responded to both surveys.
• Major weight gain meant gaining 10% or more of one's baseline body weight, based on self-reported weights in 2017 and 2022.
• Participants reported their walking, brisk walking, jogging, and running in their free time (including active commuting) over the past year; activity was grouped as vigorous (≥ 60 metabolic equivalent of task [MET]-h/wk and vigorous-intensity activity), moderate (≥ 20 MET-h/wk, including hitting the 60 MET-h/wk mark using moderate-intensity activity only), or low (< 20 MET-h/wk). 
• Sitting outside of work was categorized as low (< 3 h/d), intermediate (from 3 to < 6 h/d), or high (≥ 6 h/d).

TAKEAWAY

• Over the 5-year period, 24.2% of women and 11.6% of men gained at least 10% of body weight.
• Compared with participants who reported vigorous physical activity, those with moderate leisure-time physical activity had 26% higher odds of major weight gain (adjusted odds ratio [aOR], 1.26; 95% CI, 1.01-1.59).
• Adults with low or moderate physical activity who also spent 3 or more hours a day sitting outside of work had 62% higher odds of major weight gain than those with vigorous physical activity who sat less than 3 hours a day (aOR, 1.62; 95% CI, 1.13-2.37).
• Participants with a baseline BMI of 25 or higher were more likely to gain at least 10% of their weight than those with a lower BMI (24.5% vs 19.6%), and the links between low activity, high sitting time, and major weight gain appeared stronger in this group.

IN PRACTICE

"The findings suggest that adults who engage in high levels of LTPA [leisure-time physical activity] may still face an elevated risk of weight gain if they spend considerable time in sedentary leisure activities. The joint category of low/moderate LTPA and high LTSB [leisure-time sedentary behaviour] showed a stronger association with major weight gain than either variable alone," the authors wrote.

"These findings highlight the importance of planning targeted interventions focused on increasing physical activity levels and decreasing sedentary behaviour to effectively prevent weight gain in young and early midlife adults," they added.

SOURCE

This study was led by Henriikka Nurminen, University of Helsinki, Helsinki, Finland. It was published online in Scientific Reports.

LIMITATIONS

The study relied on self-reported measures for weight, height, physical activity, and sedentary behaviors, which may have introduced reporting bias. The analysis did not account for diet quality, and the sample was predominantly female. In addition, the observational nature of the study prevented the establishment of a causal relationship between behavior patterns and weight change.

DISCLOSURES

Some of the authors reported receiving funding from the Ministry of Education and Culture, Finland, the Juho Vainio Foundation, and the Medical Faculty at the University of Helsinki. No competing interests were reported.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.