London School of Hygiene & Tropical Medicine

Doing at least one hour of physical activity per day can offset the increased mortality risk associated with sitting for at least eight hours per day, according to research recently published in The Lancet.

Conducted by the Norwegian School of Sports Sciences and the University of Cambridge, the study analysed one million people and found that sitting for eight hours a day but being physically active was associated with a lower risk of death compared to sitting for fewer hours a day and not being physically active.

Physical activities to combat the risk included brisk walking (at 5.6 km/h) or cycling for pleasure (at 16 km/h). The study also noted that time specifically spent watching the television had a slightly higher associated risk of death than the risk with total sitting time. However, this could be due to a number of factors such as watching TV after eating dinner, affecting metabolism.

Should those of us who spend long hours sitting down stand up and take note? And how easy is it for those to offset this risk? Steven Cummins, Professor of Population Health at the School said:

"This important study shows that it is possible to reduce the effects of prolonged sitting by undertaking 60-75 minutes of moderate physical activity per day. Though measures of physical activity used are self-reported, the prospective nature of the analyses, along with the consistency of the findings, makes a good case for a possible causal link.

 "The reality is that most of us have relatively sedentary occupations, which makes undertaking the amount of moderate physical activity recommended by the authors seem like a challenge. However, there are simple and effective ways to increase everyday physical activity. For example, ditching the car and using more active ways of getting to work through using public transport, walking or cycling, has been shown to increase physical activity and improve cardio-metabolic health."

Earlier this year, Dr Ellen Flint, Lecturer in Population Health at the School published research that linked walking and cycling to work with lower body fat and BMI in mid-life. That study showed that even commuting via public transport showed reductions in BMI and percentage body fat over those that took the car. The strongest association was seen in those who commuted by bicycle, followed by walking, and that the further the distance travelled the greater the reductions.