Two research teams at the University of California San Diego (UCSD) School of Medicine sought to understand sedentary lifestyles, as a lack of physical activity is known to cause health problems and age-related chronic illnesses.
In one study, published in Journals of Gerontology: Medical Sciences (October 12, 2020), the research team observed activity levels of nearly 6,000 women (ages 63 to 97) in partnership with the Women's Health Initiative. Participants wore an accelerometer for one week to measure how much time they spent sitting, standing still or moving.
Participants who spent the most time standing had a 37% percent lower risk of death when compared to the group who didn't stand up as often. In fact, a lower risk of death was observed by standing still for as little as 30 minutes per day. The positive effects of standing were even stronger when participants were moving around at the same time.
"Standing is a feasible approach to interrupt long periods of time sitting that takes place throughout the day," said John Bellettiere, PhD, professor of epidemiology at UCSD School of Medicine. "We find this most beneficial for older adults who may not be able to partake in moderate-to-vigorous activities any more, but can still follow a healthy aging lifestyle safely just by replacing sitting with standing up more."
In another study, published in BMJ Open Sport & Exercise Medicine (October 12, 2020), researchers at UCSD School of Medicine examined physical activity data collected as part of a survey of rural farmers in Malawi, whose lives are minimally affected by technology, and compared it to lifestyles of Americans. To collect the data, researchers had 414 farmers in Malawi (ages 15 to 85) and 3,258 Americans in the same age range wear an accelerometer for a week.
The findings showed noticeably higher levels of activity among the rural population versus the U.S. Specifically, Americans spend nearly two more hours of sedentary time each day. Moderate, vigorous and light activity levels in rural Malawi were substantially higher and sedentary time much lower than those observed in the U.S. sample. In addition, the farmers met current physical activity guidelines 94% of the time, compared to only 55% of Americans. However, the researchers noted that this may be due in part to the fact that the Malawi farmers work in predominantly subsistence and non-mechanized agriculture for household food security.
"This study hints at the profound impact of technologically oriented lifestyles that are becoming ever-more dominant throughout the world," said James Sallis, PhD, Distinguished Professor Emeritus of Family Medicine and Public Health at UCSD School of Medicine. "As humans, we are designed to be active, and now we know how much our health depends on it. For people in most high-income countries, we need to put a higher priority on efforts to help them get out of their chairs and move around more throughout the day. For highly active people in low-income countries, food security is a higher priority."
