Washington, Sep 9 (IANS): Exercise has been shown to reduce anxiety and stress, but now in a major study, the researchers have revealed that it may not be enough for the levels caused by Covid-19.

People who reported increasing their physical activity after the start of Covid-19 stay-at-home orders reported higher levels of stress and anxiety than those whose activity levels stayed the same, the study, published in the journal PLOS ONE reported.

"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 from the Washington State University.

For the study, the research team analysed data from over 900 pairs of identical and same-sex fraternal twins from the Washington State Twin Registry.

Of the survey respondents, 42 per cent reported decreasing levels of physical activity since the Covid crisis began, and 27 per cent said they had increased their activities. Another 31 per cent reported no change.

Participants were asked about changes in their physical activity compared to one month previous.

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.

But surprisingly, many of the respondents who increased their physical activity felt the same way.

The researchers found that the association between decreased physical activity and stress was confounded by genetic and environmental factors.

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.

"It's not necessary that exercise won't help you personally manage stress. It's just that there is something genetically and environmentally linking the two," Duncan said.

Recently, a study, published in the journal Behavioural and Cognitive Psychotherapy, revealed that early identification and treatment is vital to avoid long-term mental health consequences from Covid-19 among children and young people.