Two thirds of British adults fail to take enough exercise, and could therefore be putting themselves at greater risk of life threatening illnesses such as cancer, heart disease and stroke.
Research by the Chartered Society of Physiotherapy found that one fifth of people took exercise only once a month or less.
Although more than four out of 10 said they would take regular exercise if it led to a longer or healthier life, and over half if it would help weight loss, the figures pointed to a significant gulf between what people say and do, the CSP said.
As a result, in July the CSP launched a UK-wide campaign called Move for Health, including a free downloadable exercise guide.
CSP spokeswoman Bridget Hurley said: “Regular physical activity is as important as eating five portions of fruit and vegetables a day, and people need to understand that you can’t keep putting it off.”