Replacing 30 Min. of Sitting with Activity or Sleep May Affect Weight
CPS-3 Accelerometry data showed how replacing 30 minutes of the day's sedentary time with other behaviors can affect weight.
The Challenge
For every minute in a 24-hour day, we¡¯re basically doing 1 of 3 things¡ªsleeping, sitting (being sedentary), or being physically active. Since you can do only one of these at a time, these behaviors are mutually exclusive. Yet, they¡¯re uniquely interrelated because the more time you spend doing one, automatically means you¡¯re spending less time doing the others.
What you¡¯re doing every minute in a 24-hour-day may also relate to your body weight. To truly understand some of the intricacies of weight change and maintenance requires consideration of these 3 behaviors simultaneously.
The Research
Erika Rees-Punia, PhD, MPH, and her ÁñÁ«ÊÓƵ research colleagues were able to analyze these 3 behaviors together in a racially diverse subset of 549 participants in the?Cancer Prevention Study-3 (CPS-3)?who agreed to be part of in?an accelerometer sub-study.
Many important factors are at play in determining our risk for gaining weight. This weight-management study provided evidence for the importance of a healthy balance of all daily behaviors ¡ª including physical activity, sedentary time, and sleep ¡ª rather than a simple focus on just physical activity.¡±
These study participants answered survey questions every 3 years like all CPS-3 participants, and in addition wore an activity monitor, or accelerometer, around their waists for 7 consecutive days except when sleeping. This amount of monitoring allows for a very accurate snapshot of how people typically spend a day compared with answering survey questions, which rely on memory.
Rees-Punia and her team used compositional data analysis methods to analyze longitudinal data that makes up parts of a finite whole¡ªlike a 24-hour day. Specifically, they looked at survey data across 3 years to see how different types of activity filled up all the time in a whole day.
The researchers analyzed accelerometer-measured time people were physically active and sitting as well as self-reported sleep time, and they explored the association of these behaviors together with 3-year weight change.
They found that the amount of time people spend sleeping, being physically active, and being sedentary is associated with a change in weight among women (but not men) and among Latinx and White participants (but not Black participants).
They also found that:
- Replacement of 30 minutes/day of sedentary time with 30 minutes of moderate-vigorous intensity physical activities (like brisk walking, jogging, or playing tennis or basketball, etc.) was associated with ~3.5 lbs. weight loss among Latinx participants.
- Replacement of 30 minutes/day of sedentary time with 30 minutes of sleep was associated with ~1.5 lbs. gain in White women and ~1.3 lbs. gain in White men.
Why It Matters?
Researchers have used these techniques for many years in nutritional and some other studies, but they¡¯ve only recently been using them in physical activity epidemiology studies.
This study of weight change, along with other types of analysis, is the first of its kind, and allowed Rees-Punia and her colleagues to model what would theoretically happen to participants¡¯ weight if they were to replace 30 minutes a day of sedentary time with other behaviors.