While preparing this article, which amounted to me sitting at my computer for about four hours, I got up from my desk at least 13 times. Some of my “work breaks” included:

• 30- to 50-second walks to the kitchen to refill my water bottle (I drink a lot of water);
• a three-minute walk outside to pick a big dandelion (it was staring me in the face);
• a one-minute jaunt to the mailbox, followed by another to the recycling bin (I get a lot of junk mail);
• three sprints up the stairs to use the bathroom (did I say I drink a lot of water?);
• three breaks for leg stretches;
• one walk around the room while talking to my wife on the phone;
• and numerous practice putts on the carpet next to my desk. (I always make the five-foot putt on the carpet—why is it so different on the course?)

I tell you this not to confess my propensity for procrastination. Rather, I hope to illustrate a very important point of how I consciously and deliberately aim to limit my sedentary behavior, and increase the amount of time I spend moving around doing all kinds of activities.

In this monthly installment of “Health Yourself,” I share the latest research on sedentary behavior, physical activity, and optimal well-being. You will be surprised by what research reveals about the negative health impact of sedentary behaviors and what you can do now to jumpstart your way toward optimal wellness.

What is sedentary behavior?

Awake sedentary behavior defines by two characteristics:

1. Expending very little energy (≤1.5 METs; see below)

2. Lying down or sitting

Anytime you are sitting or lying down, watching TV, playing video games, using the computer, reading, driving, or working at a desk you are engaging in sedentary behavior.

Sedentary behavior is on the rise

Worldwide, people are less active today than they were decades ago. Physical activity associated with work, home, and transportation has declined substantially. Some examples may shock you.

A recent national survey of more than 5,700 Americans found their average sedentary time was just over eight hours per day—that equates to roughly half of a person’s waking hours!

The situation with children is no better. Recent evidence indicates on a daily basis children in Canada and the U.S. log more than six hours of sedentary behavior, mostly lying or sitting in front of the TV, computer, or other screen-based devices. All these sedentary hours are added to the time spent sitting at school. In fact, a recent study in Australia reported about 70 percent of class time, including physical education, was completely sedentary. While slightly better than class time, children also remained sedentary for most of their lunch and recess periods.

Meanwhile, for all Americans, the sedentary act of driving increased from 67 percent of all trips to work in 1960 to 88 percent in 2000. By 2011 it climbed to nearly 90 percent. In 1969 about 40 percent of U.S. children walked or rode their bikes to school; by 2001 only 13 percent did. In 2011 less than 10 percent were walking or riding.Add it up and it’s clear: Globally the world’s population has embraced sedentary living behaviors. We are becoming a population of “homosedentarians” and we are paying the price with increasing rates of chronic disease.

Why is sedentary behavior so bad?

Cumulative research evidence from around the world suggests it is total sedentary time per day that closely associates with health risk. So even though you might go for a walk, jog, or run for 60 minutes per day (which would meet most guidelines for attaining “adequate” physical activity), if you are sedentary the rest of the day, you increase your risk of developing chronic disease because you are more sedentary than active.

A recent study of 17,000 Canadians reported time spent sitting positively associated with increased risk of all-cause and cardiovascular-disease mortality. In fact, those who sat the most were about 50 percent more likely to die during the follow-up period than individuals who sat the least, even after controlling for age, smoking, and physical activity levels. It was suggested that sitting for extended periods of time probably alters certain physiological processes that control sugar or fat metabolism, or that initiate inflammatory processes in the arteries that link to chronic disease progression and mortality risk.

Physical activity science

Physical activity represents any movement engaging large muscles of the body (arms, legs, torso, back) that cause you to expend energy (expressed in kilocalories per minute—kcal/min).

Exercise scientists measure physical activity in metabolic equivalents, or METs. One MET defines as the energy expenditure (kcal/min) it takes to sit quietly. All you really need to know is that by convention, 1 MET is considered to be the resting metabolic rate equivalent to about 1.5 kcal/minute energy expenditure. Different physical activities can be graded based on their MET equivalency. Here are some examples of light, moderate, and vigorous physical activities and their MET values.

Light physical activity = an intensity between 1.5-3 METs

• Walking slowly (less than 3 mph).
• Household activities: washing dishes; preparing food; ironing; light cleaning; and doing arts and crafts.
• Leisure activities: playing billiards, croquet, and/or darts; fishing; power boating; and playing most musical instruments.

Moderate physical activity = an intensity between 3-6 METs

• Walking between 3-4 mph.
• Household activities: washing windows or the car; sweeping, vacuuming, and mopping floors; carrying wood; mowing the lawn; and carpentry.
• Leisure activities: dancing; playing golf, badminton, and/or tennis (doubles); shooting baskets; leisurely biking on flat surfaces; and sailing, wind surfing, and leisurely swimming.

Vigorous physical activity = an intensity above 6 METs

• Walking, jogging, or running at 4 mph or faster.
• Household activities: shoveling sand, coal, or snow; carrying heavy loads like wood or bricks; and active digging/gardening.
• Leisure activities: playing basketball; biking fast on flat surfaces; cross-country skiing; swimming (hard); and playing casual soccer, tennis (singles), and competitive volleyball.

Increase sedentary interruption

While we can’t eliminate all sedentary behaviors, we can increase the number of sedentary interruptions we take to reduce the total sit time, even if it’s only stand up, sit down; stand up, sit down; repeat.

Of course, it should be everyone’s goal to increase the amount of moderate-to-vigorous physical activity we engage in daily. Participation in a regular moderate physical activity program has proven to be an effective method to reduce or prevent a number of functional declines associated with aging.

Benefits of Decreasing Sedentary Behaviors

• Promotes weight loss, especially fat loss
• Improves the immune system
• Reduces the risk of heart disease
• Lowers the resting heart rate
• Improves balance and coordination
• Reduces the risk of developing colon and breast cancer
• Improves appearance
• Maintains or improves joint integrity
• Increases and maintains bone mineral density
• Provides protection against injury
• Helps manage stress more effectively
• Promotes more restful sleep

It pays to sit less, move more. . .a lot more!

In a recent study in Australia, 168 men and women aged 30-87 wore an accelerometer to measure total body movement for seven consecutive days. The accelerometer was able to record interruption from sedentary behavior—standing from a sitting position or walking a short distance, much like the activity I tracked while writing this article. The study revealed that the greater the number of breaks taken from sedentary behavior, the lower the amount of body fat accumulated and the lower the levels of blood glucose and blood lipids. This was true even if the total amount of sedentary time and physical activity time were equal between individuals—the ones who took breaks more frequently during their sedentary time were less fat, had better metabolic health variables, and felt better. This study provides evidence of the importance of avoiding prolonged uninterrupted periods of sedentary (primarily sitting) time.

So what are you waiting for? Stand up and get moving.

References:
Biddle, S.J.H., et al. (2004). Physical Activity and Sedentary Behaviours in Youth: Issues and Controversies. J. R. Soc. Promot. Health, 124(1): 29–33;
Healy, G., et al. (2008). Breaks in Sedentary Time: Beneficial Associations with Metabolic Risk. Diabetes Care, 31 (4), 661-666;
Katch, F.I., and Katch V.L. (2000). The Fidget Factor: The Easy Way to Burn Up to 1000 Extra Calories Every Day. Andrews McMeel Pub.;
Katzmarzyk, P.T., et al. (2009). Sitting Time and Mortality from All Causes, Cardiovascular Disease, and Cancer. Medicine and Science in Sports and Exercise, 41 (5), 998-1005;
Owen, N., et al. (2010). Too Much Sitting: The Population Health Science of Sedentary Behavior. Exerc. Sport Sci. Rev. 38(3): 105–113;
Pate, R.R., et al. (2008). The Evolving Definition of Sedentary. Exerc. Sport Sci. Rev. 36(4): 173–178;
Tremblay, M.S., et al. (2010). Physiological and Health Implications of a Sedentary Lifestyle. Appl. Physiol. Nutr. Metab. 35(6): 725–740.
Wijndaele, K., et al. (2011). Television Viewing Time Independently Predicts All-cause and Cardiovascular Mortality: The EPIC Norfolk Study. Int. J. Epidemiol. 40(1): 150–159;
Zimmerman, F., & Bell, J. (2009). Associations of Television Content Type and Obesity in Children. American Journal of Public Health, 100 (2), 334-340.