'Nearly 80% do not exercise enough'
Almost eight out of 10 people in England fail to do enough exercise, research on more than one million adults suggests.
People who are poorer and those with lower levels of education are least likely to exercise, but most adults are way below recommendations on the amount of activity needed to stay healthy.
However, blue skies and warm weather prompt people to take up exercise compared to the winter months.
The study, funded by the Economic and Social Research Council and led by researchers at the University of Bristol, examined data from the Active People Surveys (APS).
This covers an individual's socioeconomic position as well as other factors such as the weather and access to sport facilities. The research found almost 80% of people did not carry out moderate exercise at least 12 times in a four-week period.
Just over 8% of people who were physically able to walk had not even walked for five minutes continuously in the previous four weeks. Participation in the most common activities was also "very low", the experts said.
Some 46% of people had not walked for leisure for 30 minutes continuously, 88% had not swam and 90% had not been to a gym in the previous four weeks. People with a degree only had a 12% chance of being inactive but those with no qualifications were three times as likely to not exercise.
Carol Propper, professor of economics at Bristol's Centre for Market and Public Organisation, said: "Physical inactivity is the most important modifiable health behaviour for chronic disease so knowing who is physically inactive is important for designing cost-effective policy interventions."
She said the findings "suggest that financial as well as cultural barriers need to be overcome to reduce the prevalence of physical inactivity."
The NHS recommends people exercise at moderate intensity for at least 2.5 hours every week.