VANCOUVER, British Columbia — Breaking up prolonged sitting with 5 minutes of standing every half hour can improve postprandial glucose metabolism just as well as can 5-minute walking bouts among overweight, postmenopausal women with prediabetes, a new study finds.
The results were presented December 1, 2015 here at the World Diabetes Congress 2015 by Joseph Henson, MD, of the Diabetes Research Centre, University of Leicester, United Kingdom, and were published online simultaneously in Diabetes Care.
"I was surprised by the standing condition, because from previous studies I would have thought that it had to be driven by energy expenditure, so people would actually have to get up out of their chair and do something physical such as walking in order to get the reductions in glucose and insulin," Dr Henson told Medscape Medical News in an interview.
"But this probably points toward something happening at the muscle level, when you change your posture from sitting to standing," he noted. The fact that there was no significant difference between standing and walking "just shows really that getting out of the chair is important. It doesn't necessarily matter what you do," he added.
Session moderator and Diabetes Care editor William T Cefalu, MD, executive director, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, told Medscape Medical News, "There's a lot of research going on now about increasing energy expenditures while at work, whether it's bicycling or standing at workstations. This is one of many papers suggesting that reducing sedentary time seemed to have a benefit."
Dr Cefalu added, "I think this information needs to be disseminated to patients. We've known for years that individuals who increase their walking in any 1 week will have fewer metabolic risk factors and better outcomes. Increasing activity will have benefit. Reducing sedentary time is an important message."
Sitting, Standing, and Walking
Study subjects were 30 postmenopausal women with impaired glucose tolerance as detected by postchallenge glucose of 7.8 to 11.0 mmol/L on oral glucose tolerance or an HbA1c between 5.7% and 6.4%.
They arrived at the lab at 8:00 am following a 10-hour fast and were all asked to sit quietly for 30 minutes, then were given breakfasts consisting of 58% fat, 26% carbohydrate, and 16% protein at 9:00 am. They were given identical lunches at noon. Blood samples were drawn at 30, 60, 120, 180, and 210 minutes postprandially.
One group was randomized to simply sit still for 7.5 hours straight (lavatory visits were made via wheelchair), while a second group stood for 5 minutes every 30 minutes, and a third group walked on a treadmill for 5 minutes every 30 minutes (total 6.5 hours sitting and 1 hour standing or walking).
All were asked to return the next morning after another 10-hour fast, and repeated the all-day sitting with the same meals and blood measurements.
Compared with uninterrupted sitting, standing reduced the postprandial rise in glucose by 34% (P = .022) compared with a 28% reduction for walking (P = .009).
Postprandial insulin concentrations rose by 20% with standing (P = .045) vs 37% for walking (P = 0.008) on the day of the intervention.
On day 2, those who had interrupted their sitting with standing on day 1 had a 19% reduction in postprandial glucose levels compared with those who had been sitting on day 1 (P = .039), while walking on the previous day reduced the glucose levels by 17% on day 2 (P = .027 vs sitting).
Differences in postprandial glucose levels on day 2 were not significantly different between those who stood or walked on day 1 (P = .877)
Insulin responses did not persist into the next day following the standing condition, but they were still significantly lower the day after walking (P = .038). Again, there were no significant differences between standing and walking groups from day 1 (P = .529).
On the other hand, neither standing nor walking reduced triglyceride levels compared with prolonged sitting.
Dr Cefalu said: "I think it was an incredibly well-done study, the way they carefully evaluated the intervention and then 24 hours later compared it with prolonged sitting.
"When you look at the reductions in glucose and insulin, it's information with great public-health benefit."
Dr Henson noted that results of previous studies of breaking up sitting time in overweight and obese adults have also demonstrated benefit and suggest that the same effect would likely be seen among other populations in addition to postmenopausal women with prediabetes.
"Logic would dictate that you'd probably find similar if not stronger associations in people with established type 2 diabetes. It appears to follow a dose-response effect," he noted.
Of course, actual exercise is still important, he pointed out.
"But the problem is a lot of individuals, particularly those with dysglycemia, many of whom are overweight or obese, don't do it. So, we need to find new ways to incorporate activity throughout the day, even if it's just standing or walking."
The research was supported by the National Institute for Health Research (NIHR) Leicester-Loughborough Diet, Lifestyle and Physical Activity Biomedical Research Unit, which is a partnership between University Hospitals of Leicester National Health Service Trust, Loughborough University, and the University of Leicester; NIHR Collaborations for Leadership in Applied Health Research and Care; and Rutland and East Midlands and the University of Leicester Clinical Trials Unit. Dr Henson has no relevant financial relationships; disclosures for the coauthors are listed in the paper. Dr. Cefalu is a consultant for Intarcia Therapeutics and Sanofi and has been a principal investigator of studies for GlaxoSmithKline, AstraZeneca, and Janssen.
Diabetes Care. Published online December 1, 2015. Article
Medscape Medical News © 2015 WebMD, LLC
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Cite this: Stand or Walk: Either Way, Breaking Up Sitting is Beneficial - Medscape - Dec 03, 2015.