Researchers, nutritionists and exercise professionals regularly proclaim the health benefits of regular cardiovascular exercise along with a healthy diet. There is solid scientific evidence that moderate- to vigorous-intensity exercise plays a meaningful role in the prevention of type 2 diabetes, cardiovascular disease, obesity and some cancers. An emerging area of research in health is examining the physiological consequences of a sedentary behavior. As explained by Katzmarzyk et al. (1), sedentary behavior is not an endpoint of the physical activity continuum, it is a distinct form of behavior that is becoming more common in civilized society. Indeed, most adults and children in the U.S. spend a great part of their waking day in several forms of sedentary behavior such as watching television, working at a computer workstation, riding in a car, traveling in a bus or train, eating a meal at a table and playing video games (1,2). The evidence is becoming quite apparent that an important goal for all health professionals is to help clients curb this sedentary behavior and get more active.
A Brief History and Contemporary Findings on Being Sedentary
Some of the early research alleging the perilous effects of sedentary behavior actually surfaced in the 1950s, when researchers showed that men in physically active jobs have less coronary artery disease during middle-age (3). The researchers added that the evidence showed active men also develop coronary heart disease later in life than men in physically inactive jobs. More recently in the Canadian Fitness Survey study (1), a prospective study looking at mortality over a 12-year period of 7,278 men and 9,735 women (18 to 90 years of age; mean age = 42 yr), the authors summarize that there were 759 deaths from cardiovascular disease, 547 deaths from cancer and 526 deaths from other causes (e.g., respiratory diseases, injuries, violence, mental disease, nervous system illnesses and digestive system disorders). After correcting the data for possible cofounders (e.g., adjustments for age, sex, smoking status, alcohol consumption, leisure time and physical activity), the researchers declared that there is a strong association between sitting and mortality risk from all causes, even with physically active individuals. Thus an important finding from this large study is that physical activity does not cancel out the ill effects of too much sitting.
How Dose Sedentary Behavior Causes Ill Health?
Presently, the majority of studies investigating the physiology of sedentary behavior have been completed with animal models. However, new insights in explaining the physiology of sedentary behavior are evolving. Hamilton et al. (4) explain that when rats are not allowed to stand, there are dramatic drops in lipoprotein lipase in the leg muscles. Lipoprotein lipase is the enzyme that seizes triglycerides out of the blood to be stored and used as fuel by the body. Thus, with consistent sitting, blood triglyceride levels climb higher, elevating the risk for cardiovascular disease (CVD) and type II diabetes. This same physiological phenomenon is hypothesized to happen in humans who spend too much of their waking day in seated behaviors. As well, Hamilton and colleagues mention that a noteworthy decrease in the HDL cholesterol is also observed from sustained periods of sitting (on a daily basis). Therefore, the research is showing that sedentary behavior appears to intensify some of the contributing factors of CVD.
Introducing 'Metabolic Profiling': An Innovative Action Plan for Weight Loss Professionals
Hamilton et al. (4) suggest health and weight loss professionals need to consider incorporating more innovative lifestyle approaches to reducing sedentary behavior (in addition to designing exercise programs). The authors suggest creating metabolic profiles for clients during their waking day and then to introduce movement interventions that will help clients move more during sedentary times of the day. In essence, a metabolic profile tracks a client's activities in 30-minute (or more) blocks of time during their waking day. Let's do a case study to better understand how to complete a metabolic profile and how to provide appropriate interventions for a client.
Metabolic Case Study
A client's Monday-Friday week consists of the following metabolic profile.
- Awakes at 7 am and completes 60 minutes of exercise (warm-up, cardiovascular exercise of combined walking/jogging, calisthenics and flexibility exercises).
- Eats breakfast (45 minutes)
- Drives to work (45 minutes)
- Works on computer workstation in seated position (4 hours)
- Takes a lunch break (60 minutes)
- Works on computer workstation in seated position (4 hours)
- Drives home (45 minutes)
- Prepares and eats dinner (60 minutes)
- Watches TV and reads in seated position (2.5 hours)
In this case study example, there are two 4-hour blocks of seated behavior at work each day as well as 2.5 hours each night of seated behavior while watching TV and reading that are appropriate for some movement interventions.
Some (but not all) intervention options to discuss with the client to break-up these sustained sitting periods at work might include:
- Stand up and walk around the office every 30 minutes
- Stand up and move every time the client needs to get some water
- Walk to the farthest bathroom in the worksite facility when going to the restroom (if multiple bathrooms are an option)
- Take a walk break every time the client takes a coffee or tea break
- Don't email office colleagues; walk to their desks to communicate with them
For the 2.5-hour time frame of watching TV and reading consider some of the following movement activity interventions:
- Get up and move during every commercial
- Take a get-up and move break every 30 minutes
- Stand up and move for the opening segment of each TV show
- At the end of reading every 4, 6 or 8 pages get up to walk around the room or house
As can be seen from the above, the goal of a metabolic profile is to help client's add more movement to sedentary periods of time during their waking day. Attempt to have them do some type of movement every 30 minutes. Some clients may also be leading sedentary weekend lifestyles. They may need a separate metabolic profile with appropriate interventions for Saturday and Sunday.
The information and research presented above suggests that sedentary behavior can be very harmful to one's health. Weight loss professionals may address this issue with creative and novel strategies, such as metabolic profiling, to help clients move more during sustained sitting periods of the day. In the long run, clients will be improving their health and burning more calories. That's a great supplement to a healthy diet and a structured exercise plan.
Kravitz, L. (2012). Move more, sit less and get healthier. Weight Management Matters, 11(2), 8-9.
- Katzmarzyk PT, Church, TS, Craig, CL, Bouchard C. Sitting time and mortality from all causes, cardiovascular disease, and cancer. Med Sci Sports Exerc. 2009; 41(5):998-1005.
- Owen N, Bauman A, Brown W. Too much sitting: a novel and important predictor of chronic disease risk? Br J Sports Med. 2009;43(2):81-83.
- Morris JN, Crawford MD. Coronary heart disease and physical activity of work: Evidence of a national necropsy survey. Br Med J.1958; December 20:1486-1496.
- Hamilton MT, Healy GN, Dunstan DW, Zderic TW, Owen NO. Too little exercise and too much sitting: Inactivity physiology and the need for new recommendations on sedentary behavior. Curr Cardiovasc Risk Rep. 2008;2:292-298.
Len Kravitz, Ph.D., is the Program Coordinator of Exercise Science and Researcher at the University of New Mexico.