Physical Inactivity and Sedentary Lifestyle

Being physically inactive or sedentary can raise your health risks. You may not get enough physical activity throughout the day, especially since sitting still can be required or encouraged in many jobs, at school, and in social situations. Learn whether you might be classified as inactive or sedentary.

Definitions of Physical Inactivity

In the 2008 U.S. National Health Interview Survey, adults are classified as inactive if they did not report any sessions of light to moderate or vigorous leisure-time physical activity of at least 10 minutes a day. By that measure, 36% of U.S. adults reported no leisure-time physical activity and were considered inactive or sedentary.

Another definition of being sedentary or physically inactive comes from the National Population Health Surveys of Canada. You are considered inactive if you expend less than 1.5 kcal/kg/day in leisure physical activities. This is the equivalent of walking a little over 1.3 miles (2 kilometers) or approximately 3000 steps. For most people, that is a walk of 25 minutes or less.

Pedometer researcher Catrine Tudor-Locke labels people inactive or sedentary if they log fewer than 5,000 pedometer steps per day. This is consistent with the other definitions, as most people will log 2,000 steps simply in daily activities around the house, such as in going from the bedroom to the kitchen to the bathroom, to the couch, etc.

You can be physically active for some part of the day, even reaching the recommended levels of physical exercise, and yet be sedentary for long periods. The Sedentary Behavior Research Network defines being sedentary as engaging in behavior where you are sitting or reclining and not expending 1.5 metabolic equivalents (MET) or more. By comparison, 1 MET is being completely at rest, while moderate-intensity physical activity such as brisk walking expends 3 to 6 MET.

Is Physical Inactivity Dangerous?

During the 1990s, researchers at the Centers for Disease Control and prevention (CDC) estimated that around 300,000 deaths each year in the U.S. are the result of physical inactivity and unhealthy eating habits. Two decades later, other researchers determined that the number of estimated deaths caused by lack of exercise and poor diet more than doubled. Physical inactivity raises the risk of death from heart disease, stroke, colon cancer, and diabetes.

Studies of sitting time are finding that long periods of inactivity during the day may increase your risks of disease, even if you get the required amount of exercise at some point during the day. Researchers found an increased risk of type 2 diabetes, cardiovascular disease, and early death.

How Can You Prevent Being Inactive?

In order to stay active and reduce health risks, health authorities such as the American Heart Association (AHA) recommends moderate-intensity exercise for either 30 minutes a day for five days a week or a total of 2 hours and 30 minutes per week. 

Walking is an easy activity to add to your day. It can work to break up sitting time and add steps hourly throughout the day, and it can also be done in bouts of walking at break time, lunchtime, and before or after the workday.

A pedometer or fitness band can show you whether you are getting enough steps so you are not inactive. Many people set a goal of 10,000 steps per day, which is an indicator you have met the goal to boost your level of physical activity. In addition, many pedometers, including Fitbit, show "active minutes" in which you have moved at a brisk pace for at least 10 minutes at a time.

Some fitness bands and apps have inactivity alerts that remind you to get up and move when you have been inactive for a period of time. They are useful for people who spend long hours at sedentary jobs or sedentary recreational activities. Moving more often may help reduce the health risks of sitting and physical inactivity.