Minutes Of Daily Exercise May Help To Counter The Effects Of Sitting

Sitting for prolonged periods of time has become common for most people. Recent surveys indicate that behavior has changed in recent months, with most people exercising less and sitting more than we were a year ago. There could be long-term health consequences from this change to being more sedentary, as multiple studies have shown links between sitting and mortality; couch potatoes are far more likely to are more like to be overweight/obese and they are more likely to die prematurely than active people.

How long would one have to exercise to offset these rather undesirable consequences? Previous research published in The Lancet suggests that adults need to exercise moderately for about 60-75 minutes daily to diminish the side effects of sitting, but this study was limited by relying on people to recall how much they had moved/sat. 

This study suggests that walking for at least 11 minutes daily could reduce the unwanted health consequences of sitting for hours on end. This study relied on objective data from tens of thousands of people on how they spent their days and found that those who spent the most time being sedentary faced the highest risks of premature death, but if they exercised they could substantially reduce that risk even if they did not move much at all. 

Data was collected from nine recent studies involving 44,370 middle-aged or older adults living in America or Europe who wore accelerometers. Combing data revealed that the participants sat a lot, averaging around 10 hours a day being sedentary and many barely moved, exercising moderately usually walking for as little as 2-3 minutes daily. Death records were analyzed for around a decade after participants joined the respective studies along with comparing lifestyles and lifespans dividing the participants into 3 groups based on how much they moved and sat; during this time 3451 participants died.  

After controlling for smoking, BMI, and other factors that might have influenced the results, being extremely sedentary was found to be hazardous with those in the top third for sitting and bottom third for activity having a 260% more likelihood of premature death than those who moved the most and sat the least. Those in the middle group for activity who exercised moderately for 11 minutes daily were significantly less likely to die prematurely than those who moved less, even if they all belong to the group that also sat the most. 

“Across cohorts, the average time spent sedentary ranged from 8.5 hours/day to 10.5 hours/day and 8 min/day to 35 min/day for MVPA. Compared with the referent group (highest physical activity/lowest sedentary time), the risk of death increased with lower levels of MVPA and greater amounts of sedentary time. Among those in the highest third of MVPA, the risk of death was not statistically different from the referent for those in the middle (16%; 95% CI 0.87% to 1.54%) and highest (40%; 95% CI 0.87% to 2.26%) thirds of sedentary time. Those in the lowest third of MVPA had a greater risk of death in all combinations with sedentary time; 65% (95% CI 1.25% to 2.19%), 65% (95% CI 1.24% to 2.21%) and 263% (95% CI 1.93% to 3.57%), respectively.”

Further analysis led the researchers to arrive at the conclusion that 35 minutes daily of brisk walking or other activities led to the greatest statistical improvement in lifespan, regardless of how many hours one sat. 

“Higher sedentary time is associated with higher mortality in less active individuals when measured by accelerometry. About 30–40 min of MVPA per day attenuate the association between sedentary time and risk of death, which is lower than previous estimates from self-reported data.”

Due to the observational nature of this study, the researchers could not prove that exercise caused people to live longer, only that physical activity, sitting, and mortality were linked. Regardless, these results strongly suggest that if we sit a lot we should be trying to get up and move more if we want to improve our longevity. 

Ulf Ekelund, who is a professor of epidemiology and physical activity at the Norwegian School of Sport Sciences in Oslo, Norway, who led the new study says that “Brisk walking is excellent moderate exercise,” he adds that in half-hour stints, or even less, might help to lengthen our lives.