A recent narrative synthesis, accepted for publication in the journal Medicine & Science in Sports & Exercise argues that whilst regular exercise is very important for good health, it cannot completely offset the harmful effects of spending long periods of time sitting (sedentary behaviour). While there is good evidence that people who are physically active are generally healthier than those who are inactive, emerging evidence shows that someone who exercises every day but also spends many hours sitting, still has a higher risk of health problems than someone who exercises and also breaks up their sitting time. The authors conclude that the popular idea that you can simply "exercise away" a sedentary lifestyle is an oversimplification.
The authors reviewed evidence from large population studies and laboratory experiments. Collectively, these studies show that exercise can reduce many of the risks linked to prolonged sitting, but it does not remove them completely. Sitting for long periods affects the body in multiple ways, such that a single daily workout cannot fully reverse the effects, including changes in blood sugar levels, fat metabolism rates, blood vessel function and inflammation. In contrast, regularly getting up, standing, walking or doing light activity throughout the day appears to provide additional health benefits beyond those gained from structured exercise alone.
The main message is that health is best supported by a balanced 24-hour approach: being physically active, reducing the amount of time spent sitting, breaking up long periods of sitting with movement, and getting enough sleep. Rather than promoting exercise as an "antidote" to sitting, the authors recommend the simpler message: “move more, sit less, and spread movement throughout the day” might be more effective and apt as it better recognises that small, achievable changes may be more realistic and beneficial. This research is important for people at risk of developing dementia or those living with the disease, as low physical activity is a significant risk factor for dementia and maintaining physical activity after a diagnosis, can be potent for maintaining long term outcomes like quality of life.
More information on this study is available here: https://pubmed.ncbi.nlm.nih.gov/42330060/
