Moderate exercise such as cycling and walking for just an hour daily may eliminate the health risks associated with sitting for eight or more hours a day, a new study has claimed. Ever since a study in 1953 discovered that bus drivers in the UK were at greater risk of heart disease compared to bus conductors, scientists have found increasing evidence that lack of physical activity is a major risk factor for several diseases and for risk of early death. Recent estimates suggest that more than five million people die globally each year as a result of failing to meet recommended daily activity levels, according to researchers from University of Cambridge in the UK. Studies in high-income countries have suggested that adults spend the majority of their waking hours sitting down. A typical day for many people is driving to work, sitting in an office, driving home and watching TV. Current physical activity guidelines recommend that adults do at least 150 minutes of moderate intensity exercise per week, researchers said. Researchers analysed 16 studies, which included data from more than one million men and women. They grouped individuals into four quartiles depending on their level of moderate intensity physical activity, ranging from less than five minutes per day in the bottom group to over 60 minutes in the top. Moderate intensity exercise was defined as equating to walking at 5.6 kilometres per hour or cycling at 16 kilometres per hour, for example. Researchers found that 60 to 75 minutes of moderate intensity exercise was sufficient to eliminate the increased risk of early death associated with sitting for over eight hours per day. However, as many as three out of four people in the study failed to reach this level of daily activity. The greatest risk of early death was for those individuals who were physically inactive, regardless of the amount of time sitting - they were between 28 per cent and 59 per cent more likely to die early compared with those who were in the most active quartile - a similar risk to that associated with smoking and obesity, researchers said. In other words, lack of physical activity is a greater health risk than prolonged sitting, they said. "There has been a lot of concern about the health risks associated with today's more sedentary lifestyles. Our message is a positive one: it is possible to reduce - or even eliminate - these risks if we are active enough, even without having to take up sports or go to the gym," said Ulf Ekelund from University of Cambridge. "For many people who commute to work and have office-based jobs, there is no way to escape sitting for prolonged periods of time. For these people in particular, we cannot stress enough the importance of getting exercise, whether it is getting out for a walk at lunchtime, going for a run in the morning or cycling to work," researchers said. The findings were published in the journal The Lancet.