It is a well-known fact that regular physical activity helps to improve health and well-being, but some researchers are not too happy with guideline.
They have found that much of the recommendations regarding the minimum amount physical activity is conflicting within countries, thus making it difficult for healthcare professionals to assess whether a person is getting enough exercise.
Around nine out of every ten men studied could be categorized as active or sedentary, depending on which guidelines were followed.
"Recommended levels of physical activity are supposed to give the public and health providers a guideline of the minimum amount of activity needed for good health, but these messages seem to vary a lot," said Dr Alan Batterham, a researcher in the Health and Social Care Institute at Teesside.
"For example, in the UK, the recommendation is that adults should do at least 30 minutes of moderate physical activity per day in periods of 10 minutes or more, five times a week.
"In the US, some guidelines recommend an overall volume of activity, recommending an average of minutes of moderate intensity activity per day, but this includes any activity you might do, even if it lasts less than ten minutes.
"So, if you did a couple of two-hour walks at the weekend, and just a little bit of activity during the week, these US guidelines would define you as sufficiently active but according to the UK guidelines from the Department of Health you would be told that you needed to do more.
"Being physically inactive is a major risk factor for heart disease just like high blood pressure and high cholesterol, so it's really important that healthcare professionals are able to identify which people should be getting more physical activity so they can give them appropriate advice and support.
"If you went to the doctor to get your blood pressure or cholesterol checked, you'd expect to get a consistent result each time, we're saying that assessments of physical activity need to be just as stringent," he added.
The study is in the online open access journal PLoS ONE.