Exercise is a known stress reliever, but the ongoing stress levels brought about by COVID-19 may be too much even for exercise. In a study conducted by Washington State University (WSU), more than 900 sets of identical and fraternal twins were analyzed from March 26, 2020, to April 5, 2020, in an effort to examine associations between physical activity and mental health. The study, published in PLOS ONE (August 2020), found that those who reported an increase in physical activity after the start of stay-at-home orders felt higher levels of stress and anxiety than those whose activity levels stayed the same.
"Certainly, people who don't exercise know that there are associations with mental health outcomes, yet the ones that increased their exercise also reported increased anxiety and stress," said lead author Glen Duncan, professor at WSU Elson S. Floyd College of Medicine. "It's hard to know exactly what's going on, but it could be that they are trying to use exercise as a means to counter that stress and anxiety they're feeling because of COVID."
Using twins in the study allowed researchers to determine if the connections between mental health and physical activity were due to genetic or shared environmental factors, or both. Participants were surveyed about changes in their physical activity compared to the previous month. Of the survey respondents, 42% reported decreasing levels of physical activity since the COVID crisis began, and 27% said they had increased their activities. Another 31% reported no change.
Those who reported a decrease in physical activity after the start of stay-at-home orders had higher levels of stress and anxiety, which was to be expected. Researchers were surprised, though, that many of the subjects who increased their physical activity felt the same way. What's more, twin pairs who differed in their perceived change in physical activity (i.e., one twin decreased their activity while the other remained the same) did not differ in their perceived stress levels, meaning that genetic factors play a role in addition to environmental ones.
"It's not necessarily that exercise won't help you personally manage stress," said Duncan. "It's just that there is something genetically and environmentally linking the two."
The researchers plan to re-interview the subjects of the study to see if anything changes as the pandemic continues.