| Break Up a Sedentary Day with Active Standing Len Kravitz, Ph.D. Introduction It is an inspiring time to be a fitness professional. Now, more than at any other period of time, we have the scientific evidence that shows the tremendous favorable impact that physical activity and exercise convenes on managing and reducing chronic diseases, improving brain health, lowering blood pressure, reducing depression and anxiety, controlling obesity and many other health benefits. In this column, we focus on three scientific publications that help define a road map of where we are headed in helping people combat sedentary lifestyles. Sedentary Behavior Terms Clarified As the young science of sedentary behavior study develops and evolves, researchers have realized a need for consistency in terminology and standardization of techniques used in this research. Enter the Sedentary Behaviour Research Network (SBRN). The SBRN (2017) is a network connecting researchers and health professionals from around the world who all share a common interested in sedentary behavior research. The SBRN currently is composed of 1273 members from 35 countries (Tremblay et al., 2017). The following are three key terminology definitions related to sedentary behavior research (Tremblay et al., 2017). 1) Sedentary behavior is any waking behavior characterized by an energy expenditure &Mac178;1.5 METs while in a sitting, reclining or lying posture. A MET, expressed as 3.5 ml oxygen/kg/min, is a method of describing the energy expenditure of activities in a way comparable among persons of different weight. 2) Physical inactivity is an insufficient physical activity level to meet present physical activity recommendations. For adults, this means NOT achieving 150 minutes of moderate-to-vigorous-intensity physical activity per week or 75 minutes of vigorous-intensity physical activity per week or an equivalent combination of vigorous and moderate-intensity activity. 3) Standing is a position in which one has or is maintaining an upright position while supported by one's feet. Furthermore, passive standing refers to any waking activity in a standing posture expending &Mac178;2.0 METs, such as standing in a conversation, standing in a line, or standing at a religious service. Contrariwise, active standing refers to a standing posture with an energy expenditure >2.0 METs such as while lifting weights, standing on a ladder and/or standing while working at a work station, such as an assembly line. How Much Energy is Required Going from a Sit to a Stand? As fitness pros, we regularly encourage clients to sit less, stand more and move a lot during their waking day. Uniquely, an emerging area of research is to quantify the metabolic benefits of interrupting sitting time with frequent bouts of standing. An original investigation by Júdice et al. (2016) recruited 50 men and women volunteers, 20-64 years, with no known diseases, to perform three randomized 10-minute conditions (in one session). It should be highlighted that prior to participating in the experimental session, participants were instructed not to consume any calorie-containing beverages or food for 8 hours. In addition, they were told not to engage in any exercise, ingest caffeine or take any type of stimulant for 48 hours prior to their study test. The three 10-minute conditions were as follows: 1) spending 10 continuous minutes standing motionless with arms resting down along the side; 2) spending 10 continuous minutes seated in a chair motionless with hands on thighs; 3) performing a sit/stand transition each minute during 10 continuous minutes. Participants stood up from the seated position and returned to the seated position in one single action movement at the 30-second mark of each minute. Therefore, they performed a total of 10 sit/stand transitions. The researchers presented the results by sex, with the oxygen consumption (ml/kg/min) data depicted in table 1. Perhaps the most noteworthy finding from this study is that 10 sit-to-stand transitions (during a 10-minute period) expends 32% more energy than just sitting for 10 minutes for both men and women. Júdice et al. extrapolated that this additional energy expenditure (during the 10 minutes) is about 3.2 kilocalories. The researchers further recap previous research that shows, on average, a typical office worker does 52 sit-to-stand transitions a day, which is about 16.6 kilocalories. These data confirm that increasing the number of sit-to-stand transitions daily, will over the long run contribute positively to caloric expenditure. Interestingly, the energy expenditure comparison of standing versus sitting (table 1) shows only slightly higher values with standing for both men (8% higher) and women (6% higher). Final Take-home Message: Although standing work stations are gaining wonderful popularity, their benefits appear to be better realized in body posture, alignment and work productivity. For enhancing energy expenditure, the public health message should be to interrupt sustained periods of sitting with sit-to-stand transitions, and of course progressively add more movement once standing. Does Changing Sitting Patterns Help Thwart Type 2 Diabetes in Older Populations? Type 2 diabetes management involves concentrated lifestyle modifications, which include weight loss, moderate intensity cardiovascular exercise and resistance training. Currently, very little is known about type 2 diabetes prevention in adults over the age of 75. With this population, moderate levels of physical activity may be too challenging to complete. A recently published investigation by Bellettier et al. (2019) provides some thought-provoking sedentary behavior findings for this special population. In this study, the researches tracked 6, 116 ethnically diverse community-dwelling women aged 63-99, with accelerometers (devices designed to objectively quantify physical activity) 24 h/day for up to 7 days. A major finding of this study was that women with the most daily sedentary time had more than two times higher odds of having diabetes as compared to women with the least amount of sedentary time. Secondly, women with the longest sustained blocks of time of daily sedentary time also had the highest odds for having type 2 diabetes. From a practical application interpretation, this study shows that when a person sits for long periods without getting up, the major weight-bearing muscles of the legs are not contracting. With no muscle contractions, these muscles are unable to efficiently utilize the circulating sugars and fats in the blood. Sustained over time, this leads to overweight/obesity and type 2 diabetes. The reduced blood flow from inactivity will eventually create an unhealthy environment for the body's blood vessels, contributing to the potential development of peripheral artery disease and blood clots. Clearly, the findings by Bellettier et al. show that interventions targeting to thwart sedentary behavior for older populations are essential for quality of life as people age. Final Take-home Message: Fitness pros should encourage older clients that breaking up long sitting bouts with light to moderate activity appears to be highly associated with protection against the development (or management) of type 2 diabetes. Reflections on this Sedentary Behavior Update The current standardization of terms and methods by the scientific community will lead to greater advances on understanding and battling sedentary behavior. From the movement perspective, the evidence visibly shows that to promote an optimal way of life for our clients, fitness pros should continue to develop and teach time-efficient daily exercise (aerobic and resistance training) programs. We also need to develop new, imaginative interventions to combat sustained periods of sitting. Fitness pros can take the lead the way in developing creative 'end of sitting' campaigns and contests to better bring more awareness to our clients and fellow citizens that yes, exercise is wonderful for health, but so is 'getting up and moving' while at work and at home. Here's a contest we all can do with our clients. First 10 clients to reach 10,000 sit-to-stands at work and home win a __________(you choose the reward). @bio:Len Kravitz, PhD, CSCS, is the program coordinator of exercise science at the University of New Mexico, where he received the Outstanding Teacher of the Year and Presidential Award of Distinction. He just released his third book, <I>HIIT Your Limit: High-Intensity Interval Training<I> (Amazon). References: Bellettier, J., Healy, G.N., LaMonte, M.J. et al. (2019). Sedentary behavior and prevalent diabetes in 6,166 older women: The objective physical activity and cardiovascular health study, Journals of Gerontology: Medical Sciences, 74(3), 387-395. Júdice, P.B., Hamilton, M.T., Sardinha, L.B. et al. (2016). What is the metabolic and energy cost of sitting, standing and sit/stand transitions? Euorpean Journal of Applied Physiology, 116, 263-273. SBRN. (2017). Sedentary Behaviour Research Network https://www.sedentarybehaviour.org/ Accessed: April 15, 2019 Tremblay, M.S., Aubert, S., Barnes, J.D. et al. (2017). Sedentary behavior research network (SBRN) -Terminology consensus project process and outcome. International Journal of Behavioral Nutrition and Physical Activity.14:75, DOI 10.1186/s12966-017-0525-8 |
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