Most adults in England do not do enough exercise, which could lead to significant health risks, research suggests.
A recent study found that 80% of adults fail to meet the government target of moderate exercise at least 12 times over a four-week period.
More than one million adults in were surveyed for the research, which was funded by the Economic and Social Research Council.
Researchers from the University of Bristol found that 8% of adults who were physically able to walk had not walked for five minutes in a row during the past four weeks.
A large number of participants (46%) had not walked for more than 30 minutes in a row.
The majority (88%) had not been swimming and 90% had not been to a gym in the past four weeks.
Carol Propper, professor of economics at the university'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."
However, the research also showed that people with a higher socioeconomic status were more likely to be active. Only 12% of people with a degree were considered ‘inactive’.
Those living in areas with more sports facilities and higher local authority spending on new facilities were also less likely to be inactive.
Propper added: "Financial as well as cultural barriers need to be overcome to reduce the prevalence of physical inactivity."
Moderate exercise is defined as an activity which can cause an adult to get warmer and breathe harder with an increased pulse rate, but they should still be able to have a conversation.