The longer you sit, the higher your risk of death from all causes.
Excessive sedentary time is exceptionally common in Western societies, and the United States is probably one of the worst. We have long known that a sedentary lifestyle is bad for your waistline and heart. All those hours sitting on your backside working or surfing the internet in front of the computer kill your metabolism and add to cortisol or stress levels. The question has always been “Does a sedentary lifestyle add to any other risks and does the risk grow with the amount of time spent sitting”? We now know that the longer total time spent sitting and longer the periods of uninterrupted sitting is associated with a higher risk of all-cause mortality.
A study published in 2017 looked at just this question. The study was entitled “Patterns of sedentary behavior and mortality in U.S. middle-aged and older adults: A National Cohort Study” and was published in the Annals of Internal Medicine. The intent of the study was to examine the association between objectively measured sedentary behavior (its total volume and accrual in prolonged, uninterrupted bouts) and all-cause mortality. The researchers used hip-mounted accelerometers to objectively measure activity versus sedentary behavior among a group of 7985 black and white adults who were all over the age of 45 years of age and living in the United States. The researchers defined mean sedentary length as prolonged, uninterrupted time spent sitting. The researchers used hazard ratios to compare the groups and adjusted them for moderate or vigorous physical activity. The median time between study and follow-up was just four years, but while pending follow-up, 340 of the participants died.
The researchers found that an increase total volume of sedentary time and longer uninterrupted sedentary time were associated with a higher risk of all-cause mortality across all four groups. Also, their analysis revealed that participants that had both the highest time spent sitting and longest bouts of sedentary time had the highest risk of death.