Physical activity is known to be a lifestyle modification that effectively prevents and treats obesity without the use of drugs. However, many people find it difficult to exercise every day, and some confine their exercise to weekends as a result.
A new study in Obesity compares these two trends with inactivity to assess their effectiveness. While obesity can cause cancers and other chronic diseases, as well as disabling osteoarthritis, physical activity (PA) can help reduce these risks. The World Health Organization (WHO) recommends that at least 150 minutes of moderate activity be carried out every week, or 75 minutes per week of vigorous PA, or a combination of both that provides equivalent PA.
Earlier research suggests that either exercise to recommended levels is effective in improving cardiovascular fitness and preventing death, whether spread out over the week or concentrated into the weekends.
The aim of the current study was to look for links between different patterns of physical activity and general fat deposition in the body. The researchers used data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018 among 9,600 adults between 20 and 59 years.
They were classified as being physically inactive, active on weekends (“weekend warriors,” WW), or being regularly physically active (RA). Adiposity was measured by dual-energy x-ray absorptiometry (DXA) and anthropometric measures.
What did the study show?
Among study participants, the mean age was 39 years, with 60% being White. WW and RA participants were more often White and more educated, with better diet quality and higher family incomes. They were also less likely to be depressed, to have high blood pressure or diabetes.
Less than 10% were WW, 37% were RA, and the rest were inactive. The WW group was most physically active at work compared to the other two groups and had the most intense and longest exercise sessions. Younger participants were more physically active than older, and males were more active than females.
The researchers found similar adiposity patterns for both WW and RA groups, compared to the inactive group, which had higher average abdominal fat deposition. That is, WW had 24% lower fat around the waist, whereas RA had 18% less, both compared to the mean measurements for the physically inactive group.
Waist circumference (WC) and whole body fat mass (FM) were also measured in all groups. While the WC was almost two times lower among the WW group compared to the inactive group, for RA, it was reduced by 131%. FM was 16% and 11% lower among the WW and RA groups vs the inactive groups, respectively.
Finally, when the body mass index (BMI) was assessed, despite it being a poor indicator of fat mass, it showed a reduction of nearly 80% among WW vs 50% among the RA group. Females showed a lower BMI than males in both active groups compared to inactive participants. That is, for WW females, the difference in BMI was two-fold lower, vs 8% in males, while for RA, the difference was one-fold vs 16% for females and males, respectively.
For all measures, WW showed lower values than RA, indicating lower adiposity, both abdominal and general fat deposition.
What are the implications?
This is the first study to explore how different patterns of physical activity are related to fat mass rather than different intensities or durations. Its importance lies in the fact that WW is not recognized as health-promoting regular physical activity by some guidelines. In this experiment, researchers showed a reduction in abdominal fat mass, compared to whole body fat mass, with both patterns of physical activity, indicating the anti-adiposity effect of physical activity.
“Our results demonstrated that individuals who cannot meet the frequency but increase duration and intensity can achieve similarly low adipose tissue as long as they meet the recommended total PA.” The findings show that recommended levels of physical activity may be effectively attained either by exercising every day or by concentrating exercise into one or two days a week, thus preventing the build-up of abdominal fat and related metabolic disease.
These findings need to be validated in comparable cohorts, including job type. Future research should also focus on how this reduction in visceral fat is brought about in either pattern and whether it is a short-term or long-term effect. Moreover, the effect of acute exercise on inflammation and insulin sensitivity remains to be explored.
Journal reference:
- Lei, L., Li, J., Wang, W., Yu, Y., Pu, B., Peng, Y., Zhang, L. and Zhao, Z. (2024) Obesity. doi: 10.1002/oby.23986. https://onlinelibrary.wiley.com/doi/10.1002/oby.23986