Exercise may not help stress enough during COVID-19, study finds

Exercise has been shown to reduce anxiety and stress, but it may not be enough for the levels caused by the novel coronavirus (COVID-19), according to a new study by Washington State University published in the journal PLOS One.

For the study, researchers analyzed data from over 900 pairs of identical and same-sex fraternal twins from the Washington State Twin Registry. Those who reported a decrease in physical activity within two-weeks after the start of stay-at-home orders had a perceived higher level of stress and anxiety, which was expected. Many of the respondents who increased their physical activity felt the same way, according to the study.

The twin survey was conducted from March 26 to April 5, 2020, in the early days of the pandemic. Washington State and many other states issued their first stay at home orders near the end of March to help curb the spread of COVID-19. Participants were asked about changes in their physical activity compared to one month previous. Of the survey respondents, 42 percent reported decreasing levels of physical activity since the COVID crisis began, and 27 percent said they had increased their activities. Another 31 percent reported no change, the researchers said.

Conducting the study with twins allowed the researchers to look at whether the associations between changes in physical activity and mental health were mediated by genetic or shared environmental factors, or both. Identical twins share all their genes; fraternal twins share approximately half of their genes; and twins raised in the same family share many formative experiences.

In the study, the researchers found that the association between decreased physical activity and stress was confounded by genetic and environmental factors. The twin pairs who differed in their perceived change in physical activity--when one twin reported decreased activity while the other remained the same--did not differ in their perceived stress levels.

Additionally, the researchers found some association between decreased physical activity and anxiety: within a pair of twins, the sibling with decreased physical activity had higher levels of anxiety than the sibling who reported no change. In addition, anxiety levels were higher among older people and women.

The researchers said they plan to survey this population again to see if the relationships between physical activity and these mental health issues persist or change.

"It's not necessarily that exercise won't help you personally manage stress. It's just that there is something genetically and environmentally linking the two,” said Glen Duncan, PhD, RCEP, lead author of the study and a professor in the Elson S. Floyd College of Medicine. “At least in the short term, it seems there is not a lot of impact from either decreasing or increasing physical activity in terms of handling stress and anxiety, but that might be different after two or three months under COVID restrictions.”

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