Ask an Expert: I know sedentary behaviour is bad, but how can I stay healthy when I need to sit so much?

Our expert explains why standing up every once in a while could be one of the healthiest additions to your routine.

We sit a lot. On average, Canadians are sedentary for more than eight hours per day, according to Statistics Canada1.  This can lead to health problems down the line. Vancouver Coastal Health Research Institute researcher, Dr. Kenneth Madden, shares what you can do to safeguard yourself against the sitting scourge.   

Q: What happens to my body when I sit for a long time?
A:
Being sedentary—sitting or lying down for prolonged periods of time while not sleeping—does cause changes in your body. Every time your muscles contract, they pump sugar out of your bloodstream. If you spend a lot of time in your day being sedentary, you are not pumping sugar out of your blood. That can prevent several fat enzymes from working properly and can lead to the kind of insulin resistance found in diabetes. 

Insulin resistance is when your body stops responding to the insulin produced by your pancreas. For example, if you eat a candy bar, your pancreas secretes insulin to control your blood sugar levels. When cells in your body fat, muscles and liver stop responding to insulin, blood sugar levels start to go up and your body reacts by producing more insulin. The more insulin you produce, the more calories you store as fat. Over several years, your pancreas may become unable to keep pace with the demand for more insulin, which can lead to pre-diabetes, Type 2 diabetes, heart conditions, larger waist circumference and liver disease. 

Q: I sit to do my job and while commuting to work. Is this bad for my health?
A:
When researchers compared people who had been constantly sedentary for eight hours each day—a typical workday—they found those who stood up less often were more insulin resistant than those who stood up periodically. The important point here is that it is not necessarily the length of time that someone is sedentary, but the frequency with which sedentary time is broken up.

Q: How often should I stand up to stay healthy? 
A:
Current guidelines recommend standing up around once every half hour. Just the act of standing up is enough to decrease your body’s insulin resistance and keep your blood sugar levels in check. 

Exercise is still important, but if, like most people, you cannot exercise throughout your day, standing up every 30 minutes is the next best thing. 

Q: Why is simply standing up enough? 
A:
The glucose channels that transport glucose out of your bloodstream only work if your muscles are firing. Simply standing up is enough to get your muscles firing and to move some of that glucose out of your bloodstream. 

Q: Do the effects of sedentary behaviour change as I age and what can I do about it?
A:
We tend to become more sedentary as we age. This can contribute to sarcopenia—the loss of muscle mass—which can further exacerbate the negative health effects of sedentary behaviour. However, exercise and strength training can help to reverse sarcopenia.

Q: Can exercise in general reverse the effects of being sedentary? 
A:
While exercise is always beneficial, it is more about reducing sedentary time that is important when it comes to preventing the negative health effects of sedentary behaviour. Walking or biking to work, taking the stairs, eating lunch standing up, using a standing desk and reducing screen time are all good ways to cut down on sedentariness. The same goes for apps or alarms that remind you to stand up every 30 minutes.

On top of that, it is also important to follow the Canadian Physical Activity and Sedentary Behaviour Guidelines to ensure you are getting enough exercise.

Dr. Kenneth Madden is the division head of Geriatric Medicine at Vancouver General Hospital and holds the Allan M. McGavin Chair in Geriatric Medicine at the University of British Columbia. His lab has examined how exercise interventions affect older adults with Type 2 diabetes and the impact of sedentary behaviours on cardiometabolic risk factors.

 

1 Ten years of measuring physical activity—What have we learned?

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