Most government guidelines call for about 30 minutes of exercise a day on five days a week, but most people don't meet this recommendation. In this study Taiwanese researchers examined if lower amounts of exercise also had health benefits. They conducted a prospective cohort study that included 416,175 adults. At the start of the study the participants filled out a questionnaire on their amount of leisure time physical activity. Based on this they were divided into five groups: inactive, low volume, medium volume, high volume, and very high volume. The participants were followed up between 1996 and 2008; average follow-up was 8.05 years. People in the low volume group exercised an average of 92 minutes per week or 15 minutes on six days per week. Compared to inactive people, those in the low volume group had a 14% lower risk of all-cause mortality, a 10% lower risk of death from cancer, and a 19% lower risk of death from cardiovascular disease. Each additional 15 minutes of exercise a day (up to 100 minutes per day) as associated with a further 4% reduction in all-cause mortality and a 1% reduction in cancer mortality. For people age 30, low volume activity was associated with about a three year longer life expectancy than being inactive. The results were applicable to both men and women, all age groups, and people who already had cardiovascular disease. Limitations of this study include its observational design. The researches cannot conclude that the health benefits they saw were only due to exercise; other factors could also play a role. According to the lead author, this is the first study to establish the minimum amount of exercise needed to get substantial health benefits.