Want to know the most efficient way to improve your fitness? Keep reading. In the largest study to date, scientists determined what types of habitual physical activity are best for improving cardiorespiratory fitness. These findings are very important as superior cardiorespiratory fitness substantially lowers the risk of cardiovascular disease, cancer, diabetes, dementia, and premature death. 

For this study, scientists used sophisticated accelerometers to accurately measure the intensity and duration of 2,070 adult study subjects’ movements over a solid week on two separate occasions, 7.8 years apart. The study subjects also underwent detailed and comprehensive measurements of their cardiorespiratory fitness on both occasions. The goal of the study was to investigate the relationship between habitual movement/exercise and physical fitness. The accelerometers measured steps per day, the amount of time spent sitting/not moving, and levels of moderate-vigorous physical activity.

The results were not surprising. Moderate-vigorous physical activity was clearly the most efficient at improving fitness. Specifically, it was three times better than simply walking and 14 times more efficient than reducing sitting time. The scientists also noted that both moderate-vigorous activity and more steps/day could partially mitigate the adverse effects of excessive sitting. 

Bottom line: Although more steps are always better, if you want to get the most bang for your time spent moving, strive to engage in more moderate to vigorous activity (typically enough movement that you are a bit breathless and somewhat uncomfortable), particularly if you have to spend lots of time sitting. 

European Heart Journal, 2021; DOI: 10.1093/eurheartj/ehab580