Berlin, May 30 (IANS): The coronavirus-induced lockdown made people 40 per cent less active, and tripled the potential risk for depression, finds a large study led by German researchers.

The significant decrease in physical activity levels and well-being can spur a hidden "pandemic within the pandemic", warned 20 scientists from 14 countries.

"Governments and those responsible for health systems should take our findings seriously," emphasised the team headed by Jan Wilke from the Institute for Sport Sciences at the Goethe University, Frankfurt.

About 13,500 participants reported physical activity levels, and 15,000 participants reported their mental and physical well-being before and during the pandemic-related restrictions in April/May 2020.

Moderate exercise like brisk walking, running, cycling decreased by an average of 41 per cent according to self-reported data; while vigorous exercise fell by a 42 per cent.

The decline in activity was particularly noticeable among people over 70 years of age, who were 56 to 67 per cent less active than before.

"We know that physical inactivity, especially in older people, can lead to changes that are difficult to reverse after only two weeks -- for example, in body fat percentage or insulin sensitivity," the researchers said.

Further, 73 per cent of the study participants said their well-being deteriorated. The perceived quality of life as measured by the World Health Organisation well-being Index, which measures mood, relaxation, activity, rest and interest, dropped on average from 68 per cent before the pandemic to 52 per cent during the first lockdown phase.

Above all, people felt "less active and full of energy" and led a life "less filled with interesting things".

The proportion of very low scores indicating a possible risk of depression tripled from 15 to 45 per cent.

"These effects were stronger among women and younger people," the study says. "More attention should be paid to the needs of women in particular, as they are significantly more vulnerable."

Nonetheless, 14 to 20 per cent of the respondents also stated that their health had improved. The reason could be more family time, greater work autonomy, fewer business trips, or a changed perception of health as possible reasons, the researchers said.