You may exercise to look good or feel fit, but from a population level, fitness is important because it protects against lifestyle diseases like cancer, diabetes, stroke and heart disease.
World Health Organisation exercise guidelines, however, have been brought into question by new research from the University of Queensland that showed we needed five times' the recommended activity for a significant reduction in risk.
Co-author and UQ School of Public Health senior lecturer Lennert Veerman said the WHO guidelines were a struggle for most Australians, let alone five times' the activity.
"In Australia, less than half the population reaches recommended heath guidelines so it is not realistic to increase them. What I would say is for people who are below the guidelines, it's a nice goal to work towards, and for people who have reached them, this research shows you can still keep going to achieve more health benefits."
How much exercise should I be doing?
To add up exercise of different intensity, the study used Metabolic Equivalent of Task (MET) minutes.
"MET minutes are a measure of effort so sitting down not doing anything is One MET. Three METs is light exercise and six METS is more intensive," Veerman said.
WHO recommends at least 600 MET minutes per week which equals 150 minutes of brisk walking or 75 minutes of running.
The study, however, found most health gains occur at a total activity level of 3000-4000 MET minutes a week which equals 12.5-16.5 hours of brisk walking or 6-8 hours of running a week.
This amount provides larger reductions in risks of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke.
"This time is not all exercise," Veerman said.
"It can be taking the stairs at work or riding to work in conjunction with public transport. It has to become a habit to be achievable."