How much Exercise / Day is required

 How Much Exercise is required to Balance Out a Day of Sitting  

We know that spending lots of time sitting down isn't good for us, but just how much exercise is needed to counteract the negative health effects of sitting down all day, is the basic question. Scientists suggest 30-40 minutes of daily moderate to vigorous exercise can counteract the health risks of a day spent sitting. Up to 40 minutes of "moderate to vigorous intensity physical activity" every day is about the right amount to balance out 10 hours of sitting still, the research says, although any amount of exercise or even just standing up helps to some extent. It's based on a meta-analysis study published in 2020 analysing nine previous studies, involving a total of 44,370 people in four different countries who were wearing some form of fitness tracker. The analysis found the risk of death among those with a more sedentary lifestyle went up as time spent engaging in moderate-to-vigorous intensity physical activity went down.

According to research, dedicating around 30 to 40 minutes daily to vigorous exercise can counter the detrimental health effects of sitting for prolonged periods. This level of physical activity is sufficient to offset the risks associated with 10 hours of sedentary behaviour. Even though any amount of physical activity or merely standing can be beneficial, the suggested exercise intensity is to engage in moderate to vigorous activities. This recommendation stems from a 2020 meta-analysis that reviewed nine studies, encompassing 44,370 individuals across four nations who monitored their activity levels with fitness trackers. The findings indicated that sedentary individuals who increased their levels of moderate-to-vigorous physical activity reduced their mortality risk. "In active individuals doing about 30-40 minutes of moderate to vigorous intensity physical activity, the association between high sedentary time and risk of death is not significantly different from those with low amounts of sedentary time," the researchers explained.

The researchers noted that individuals who engage in 30-40 minutes of moderate to vigorous intensity exercise, such as cycling, brisk walking or gardening, can neutralize the heightened risk of premature death associated with extended periods of sitting. This effect is evident in the data from thousands of participants across various studies. In other words, putting in some reasonably intensive activities can lower your risk of an earlier death right back down to what it would be if you weren't doing all that sitting around. While meta-analyses like this one always require some elaborate dot-joining across separate studies with different volunteers, timescales and conditions, the benefit of this particular piece of research is that it relied on relatively objective data from wearables, not data self-reported by the participants.

At the time, the study was published alongside the release of the World Health Organization 2020 Global Guidelines on Physical Activity and Sedentary Behaviour, put together by 40 scientists across six continents. The British Journal of Sports Medicine (BHSM) also put out a special edition to carry both the study and the revised guidelines. "As these guidelines emphasize, all physical activity counts and any amount of it is better than none," said physical activity and population health researcher Emmanuel Stamatakis from the University of Sydney in Australia. "People can still protect their health and offset the harmful effects of physical inactivity." The research based on fitness trackers is broadly in line with the 2020 WHO guidelines, which recommend 150-300 mins of moderate intensity or 75-150 mins of vigorous intensity physical activity every week to counter sedentary behaviour.

Walking up the stairs instead of taking the lift, playing with children and pets, taking part in yoga or dancing, doing household chores, walking, and cycling are all put forward as ways in which people can be more active, and if you can't manage the 30-40 minutes right away, the researchers say, start off with little bit. Making recommendations across all ages and body types is tricky, though the 40-minute time frame for activity fits in with previous research. As more data is made available, we should learn more about how to stay healthy even if we have to spend extended periods of time at a desk. "Although the new guidelines reflect the best available science, there are still some gaps in our knowledge," said Stamatakis. "We are still not clear, for example, where exactly the bar for 'too much sitting' is. But this is a fast-paced field of research, and we will hopefully have answers in a few years' time." Meta-analyses require careful synthesis of data from various studies that may have different participants, durations and conditions. However, the advantage of this study is its reliance on more objective wearable device data rather than self-reported information from the subjects.