Next time you are in the midst of an epic, nearly motionless stretch of time — staring for hours at a computer, television or phone screen, for example — consider that you may be putting your body at risk for a host of silent threats. Consider also that you most likely live in a world that encourages those threats to take hold.
A new study aims to test two strategies for breaking up prolonged periods of sitting with windows of exercise. One study group will take frequent exercise breaks throughout the day while the other volunteers will walk briskly in a single session.
The primary goal of the research is to improve blood glucose control in patients with overweight or obesity who are at risk for Type 2 diabetes, a disease that impairs the body’s ability to regulate blood sugar with insulin.
Dr. Audrey Bergouignan is leading the study. She’s an assistant professor of medicine in the Division of Endocrinology, Metabolism and Diabetes at the University of Colorado School of Medicine.
More broadly, Bergouignan and her team will study possible changes to tissue, cells, proteins, and the whole body that may occur from the exercise regimens.
Bergouignan, who has a background in the fields of evolution and ecology, has spent 20 years studying and addressing the adverse health effects of sedentary behavior.
“I am trying to understand what is the impact on the body, on health outcomes and the underlying mechanisms” of too much sitting and lack of exercise, she said.
It’s a fruitful area for investigation. A host of research, summed up in a 2019 Jama Network research review, shows that the more time people spend sitting, the more they are vulnerable to overweight and obesity, cardiovascular disease, Type 2 diabetes, cancer and even early death. Yet the same report notes that between 2007 and 2016, the number of hours adolescents and adults spent sitting each day increased from 7.0 to 8.2 and from 5.5 to 6.4, respectively. And those numbers don’t include the effects of the COVID-19 pandemic, which bound so many close to home with shutdowns of businesses and schools, remote work, virtual meetings and other disruptions that made inactivity easier.
Meeting the need to move
The obvious answer to breaking this sedentary spell, of course, is physical activity – in short, getting off the couch and out of the chair and finding ways to move. The Department of Health and Human Resources Physical Activity Guidelines for Americans recommends at least 150 minutes of moderate-intensity physical activity a week for adults and at least 60 minutes of the same daily for children and adolescents to improve their sleep, boost their energy and reduce their risk of chronic disease.
But getting people to modify entrenched sedentary habits is hard, Bergouignan says. That’s because modern society, with its ever-present screens, auto-centric communities and frequent lack of pedestrian-friendly options, makes it all too easy to sit, she says.
“We have engineered physical activity out of our daily lives,” Bergouignan says. “In every single sphere – work, transportation, leisure – sedentary behaviors are ubiquitous, and it is hard to get away from them.” The consequences of a culture of inactivity are sobering, she adds.
“We know that sedentary behaviors are one of the leading causes of death in the world,” Bergouignan states. “An employer is supposed to provide employees with an environment that is safe from pollution, noise and injury. But an employee sitting for eight hours a day is at a major risk for chronic disease.”
The 45-minute, out-of-the-chair challenge
Bergouignan’s randomized three-month study aims to enroll 66 patients and divides them into two groups. The “BREAK” group will exercise a total of 45 minutes a day, five days a week, with their exercise broken into five-minute “bouts” of brisk walking nine times a day. The “ONE” group will also walk briskly for 45 minutes, but in a single session. At the conclusion of the trial, researchers will measure participants’ plasma blood sugar concentrations at regular intervals with an oral glucose tolerance test – a key indicator of the body’s ability to metabolize sugar – and compare the results to the numbers collected at the start of the study.
They hope that the data reveals whether the approaches help to lower blood sugar levels, and if so, which of the two does so more effectively.
In addition to the oral glucose tolerance test, the trial includes a number of screening measurements, including lab tests, histories and physicals, and two separate measurements of individuals’ sedentary behavior and physical activity with an electronic device. The research team will also conduct an overnight session in a sealed room at UCHealth University of Colorado Hospital fitted with a whole room calorimeter – an instrument that allows researchers to measure, for example, the total amounts of carbohydrates, proteins and lipids burned by the participants over a 24-hour period. The room thus will supply important clues to changes in the participants’ metabolism that may affect their ability to break down sugar efficiently.
For the three-month trial period, individuals randomly assigned to either the BREAK or ONE group will receive Fitbits to track their activity and monitor their adherence to the study protocol. In the first four weeks, they will also work with a personal coach – a registered dietitian from the Anschutz Health and Wellness Center, who will help to guide them toward strategies for maintaining healthy lifestyles, Bergouignan said. The intervention period includes another overnight session in the calorimetry room.
Reaping the benefits of activity
The current study is the latest in a long line of research conducted by Bergouignan and others that point strongly not only to the benefits of sitting less but also reducing periods of prolonged sitting. For example, a recent review of research in the journal Sports Medicine concluded that frequently interrupting long periods of sitting with standing and especially “light-intensity walking” could help to control glucose levels in the periods after meals.
Bergouignan’s work has focused on an even broader variety of benefits people could reap by getting out of their seats. In a 2016 study of office workers, she and her colleagues advocated for “microbursts” of activity throughout the day to improve energy levels and mood and reduce fatigue. They also found that compared to a single long period of activity, these short bursts did a better job of helping people sustain these positive effects throughout the day.
A 2018 study that Bergouignan co-authored also showed that both short bursts and longer, single-activity periods helped overweight or obese sedentary adults boost their activity, expend more energy and improve their insulin sensitivity – a key to helping the body manage its blood sugar levels.
Solving the sedentary puzzle
That study, however, also noted that the different activity periods did not reduce the total amount of time the participants spent sitting. That is one of the knotty problems Bergouignan hopes to address with her latest trial and beyond. Despite the demonstrated benefits of breaking up sedentary behavior, the tools to help people achieve them remain elusive. A recent Diabetes Care commentary observed, “A consistent theme has been the increased emphasis given to achieving a healthier ‘balance’ between time spent engaging in sedentary behavior and total physical activity time although the ‘how to’ achieve a more desirable balance has received less attention.”
The stringent requirements and sophisticated technology involved in Bergouignan’s new study underpin that straightforward objective. Findings from the trial could give primary care providers, for example, a simple, evidence-based tool to help their sedentary patients avoid Type 2 diabetes or decrease the number of medications the more than 30 million people with the disease need to manage it.
“Physical activity is the cornerstone of management for Type 2 diabetes,” Bergouignan said. “My goal at the end of the study is to be able to help people change their lifestyles in the long run and place activity at the center of their daily lives.”
To volunteer for the study or get more information about it, email [email protected].