More Frequent, Longer Movement Breaks Can Attenuate Harms of Sitting

Regular, light walking breaks can lead to blood-pressure benefits for people who live a sedentary lifestyle, according to new research. Although the breaks taken in this small study did not have a consistent effect on glycemic control, the researchers say the data go beyond “sit less and move more” to provide more-specific advice on how to do so.

The negative cardiovascular effects of sitting for long periods of time have been demonstrated in several studies, with the most recent physical activity guidelines from the US Department of Health and Human Services suggesting less sitting and more movement throughout the day.

However, senior study author Keith M. Diaz, PhD (Columbia University Medical Center, New York, NY), told TCTMD this advice isn’t clear enough. “When we tell people they should eat fruits and vegetables, we tell them how many fruits and vegetables they should eat. When we tell somebody they should exercise, we tell them how much they should exercise. So telling someone just to sit less, move more is it is really not helpful in terms of goal setting behavior change,” he said.

The findings, which were published online this week in Medicine & Science in Sports & Exercise, should encourage all sedentary adults to walk for 5 minutes every half hour, Diaz said. “If you want to offset the harms of sitting, that is how much or how frequently you should move. . . . But even if that is too much, if someone cannot get away from their desk every half hour, even moving every hour is still good enough and it is still going to lower your blood pressure and have some health benefit.”

Commenting on the study for TCTMD, Scott Lear, PhD (St. Paul's Hospital, Vancouver, Canada), said the findings give “more strength” to the clinical messaging that has been touted for years regarding physical activity. He called for more public health messaging on this topic and a greater integration of computer or cell phone alarms that motivate office workers, especially, to get up from their desks on a regular basis.

Both Diaz and Lear cited the mental health benefits of regular movement breaks as well. Diaz specifically called upon employers to “recognize that sitting is an occupational hazard” and to motivate the workforce “to take regular walking breaks, [which] is beneficial ultimately for work performance or productivity because employees are going to be come back from their break feeling more reenergized, refocused, and in a better mood.”

Break Effects

For their crossover design study, Andrea T. Duran, PhD (Columbia University Medical Center), Diaz, and colleagues randomized 11 adults (mean age 57 years; 54.5% male) to five different 8-hour sedentary scenarios conducted in their lab with either no movement breaks (control) or light-intensity walking breaks (2.0 mph on a treadmill) every half hour for 1 minute and 5 minutes, as well as every hour for 1 minute and 5 minutes. Their glucose and blood pressure were measured every 15 and 60 minutes, respectively.

Telling someone just to sit less, move more is it is really not helpful in terms of goal setting behavior change. Keith M. Diaz

Compared with controls, only participants randomized to walking for 5 minutes every half an hour demonstrated a significant attenuation of glucose levels with an area under the curve of 11.8 (P = 0.017). All doses of walking breaks led to reductions in systolic BP (P < 0.05 for all), but the largest mean decreases were seen when moving every hour for 1 minute (-5.2 mm Hg; P < 0.001) and every half hour for 5 minute scenarios (-4.3 mm Hg; P = 0.003).

Additionally, compared with the no-movement group, all periodic-break groups saw decreases in participant fatigue and total mood disturbance scores, with the largest reductions seen for those who walked for 5 minutes both every hour and half hour.

Diaz said he was “really struck by how robust and large the effects were for blood sugar levels. Moving for 5 minutes every half hour reduced a blood sugar spike after a meal by almost 60%. Those are levels that you would typically expect to see if a person is doing insulin injections or taking diabetes medication to control their blood sugar levels. These were, I think, quite sizable effects.”

Also, he continued, the fact that even light-intensity movement had these effects was unexpected. “Walking for 1 minute every hour still lowered blood pressure by 4-5 mm Hg,” Diaz summarized. “It didn't change glucose, which we were disappointed by, but that we still saw an effect on blood pressure with such a light frequency every hour for just 1 minute, we weren't expecting to see. That it still reduced blood pressure that much was quite surprising.”

Next, Diaz said he hopes to take this research “into the real world” to gauge the long-term effects of these kind of breaks over more than a single day. “Based off of the long-term studies that have been done thus far, I do not think there are long-lasting effects to this,” he guessed. “I think this is about the acute effects, this is about regular movement being like a medication that just like every day you to take your blood pressure medication to keep it under control and manage it, that every day you have to move frequently throughout the day.”

While regular light walking might not change a person’s cardiorespiratory fitness, it will help to manage BP and blood sugar, however, Diaz said. “It is about managing the systems and not necessarily improving them.”

‘Auto Shutoff’

To Lear, it makes sense that more frequent and longer duration breaks lead to greater effects. “I like to use the analogy of those cars that have auto shutoff when you come to a stop light, in that when you are sitting down, your body starts to shut down,” he said. “And the longer you sit, the more it shuts down.”

The findings “dovetail” with research on so-called “exercise snacks” of more-intense physical activity conducted in small doses throughout the day, according to Lear, although more-sedentary adults should be encouraged that they’ll still see results with lower-intensity movement. “Even the light activity has benefits in terms of giving you energy boost, a bit of creativity, and productivity,” he said.