British researchers say the public may be getting the wrong message about exercise -- believing that moderate exercise is sufficient.

The study, published in Preventive Medicine, finds 56 percent of men and 71 percent of women believe moderate activities -- like walking -- best promote health.

Study lead author Gary O'Donovan, exercise physiologist at the University of Exeter says Britain's department of health guidelines that recommend moderate exercise since l995 should be changed to vigorous activity.

"Time and time again, the largest and most robust studies have shown that vigorously active individuals live longer and enjoy a better quality of life than moderately active individuals and couch potatoes," O'Donovan said in a statement. "It's extremely worrying that British adults now believe that a brief stroll and a bit of gardening is enough to make them fit and healthy."

While 30 minutes of brisk walking per day might be sufficient to reduce the risk of breast cancer, O'Donovan believes regular participation in vigorous exercise is probably necessary to reduce the risk of prostate and colorectal cancers.

O'Donovan warns sedentary adults should first consult their doctor and complete a six-to-12-week program of moderate exercise before beginning vigorous exercise.