The nation's lack of physical activity is a "silent epidemic", health officials said.
Lack of exercise causes the same level of ill health that smoking does, experts said, but despite this only a minority of people in England get enough exercise.
The National Institute of Health and Clinical Excellence (Nice) has issued new guidance to encourage local authorities, schools, workplaces and other institutions to get more people active.
Strategic and scientific adviser to the National Obesity Observatory Dr Harry Rutter, who worked on the new guidance, said: "Only a minority of people in England get enough physical activity to improve their health.
"This creates a huge and often invisible burden of illness and reduced quality of life, but most people seem unaware of that burden.
"Across the population, lack of physical activity causes roughly the same level of ill health that smoking does.
"We all face barriers in changing our lifestyles and many of us feel we don't have the time or the inclination to add regular physical activity into our lives - it can be very difficult to break old habits and change behaviour.
"But walking and cycling to work, to school, to the shops or elsewhere can make a huge difference.
"This guidance aims to help people in local authorities, public health professionals, schools, workplaces, the NHS and many others to make the changes that are needed to support this safe, healthy and mostly enjoyable physical activity."
He added: "We have a silent epidemic of lack of physical activity and here we have a wonderful opportunity to try and do something about it."