Sitting Can Be Good for the Circulatory System

Posted by Herman Miller on 5 January 2012

Tags: Herman Miller, Chair

What We Know:

Physical inactivity is a risk factor for cardiovascular disease, and it is becoming increasingly prevalent. It ranks similarly to cigarette smoking, high blood pressure, and elevated cholesterol as contributors to heart ailments. When a person’s activity level declines, the rate of heart disease increases. What’s more, less active, less-fit persons have a 30 to 50 percent greater risk of developing high blood pressure (New York State Department of Health, 2008). Only 30.9 percent of U.S. adults report engaging in leisure-time physical activity (American Heart Association, 2008).

Heart rate is increasingly considered an independent risk factor of cardiovascular disease (Ferrari et al., 2005), meaning it has a significant contribution—among established risk factors—to an outcome like cardiovascular disease. Based on a study of 25,000 patients, resting heart rate was shown to be an independent risk predictor of cardiovascular mortality's (Diaz et al., 2005). A reduction in heart rate decreases the work of the heart; therefore, it decreases oxygen demand and energy needs of the heart while simultaneously resulting in an increase in coronary blood flow. That is, as resting heart rate decreases, the risk of death from cardiovascular disease decreases.

In addition to lowering risk, a decrease in heart rate can improve cognition. When people feel better, they are less distracted by their physical state, which can lead to better performance. A relationship between heart rate and cognition was suggested by research conducted in the 1960s and 1970s, which revealed that a deceleration in heart rate during the anticipatory period preceding a task was associated with improved cognitive performance (McCraty et al., 2006). And in the 1980s, researchers learned that a decreased heart rate allows the brain to receive sensory information more often, leading to better cognitive performance (McCraty et al., 2006).

Therefore

People who don’t engage in regular physical activity, and who spend a lot of time sitting, are already at risk for cardiovascular disease. If they can lower their heart rate, they can reduce their risk (Freedman, 2008). It’s not only a health-positive factor, meaning that lowering the heart rate can improve one’s health, but also a benefit to one’s ability to think, since reduced heart rate is associated with improved cognitive performance.

Design Problem:

Work—and play—have changed dramatically since the early 1990s as technology has come to dominate people’s lifestyles. People tend to sit too long without moving. In fact, many chairs restrict the body’s movement. Ultimately the sitter’s internal systems can be affected. One approach to promoting movement in a work chair would be to design one with a dynamic seat and backrest. Doing so would require a surface that automatically conforms to a sitter’s micro-movements and distributes weight evenly. This would allow the seat to take on the greater burden of supporting more weight while providing stability. It would also reduce seated pressure and increase blood circulation to improve oxygen flow and decrease heart rate.

Another design aspect that would promote movement is the shape of the backrest. A work chair with an upwardly tapered backrest would provide more flexibility to encourage torso movement and allow the sitter’s arms to swing freely. Free to move, the sitter’s chest cavity would open up more than in a chair with a conventional wide backrest allows. As a result, lungs which are not constructed could enable a sitter to take deeper breaths, thus requiring fewer breaths per minute. Taken together, these features would promote movement while seated. And movement, as research has shown, is the key to good health. It keeps blood circulating and oxygen entering the lungs to feed the brain so people can think better.

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