Excessive sitting is as dangerous as smoking.  A large-scale study from the University of Leicester in Britain, published in the medical journal Diabetologia, compared disease rates between the most active and least active among a broad cross-section of adults.  The researchers discovered that the least active individuals – those who sit all day long – had a:

•     147 percent increased risk of heart attack or stroke
•     112 percent increase in the risk of developing diabetes
•     90 percent greater risk of dying from a cardiac event
•     49 percent greater risk of premature mortality

Although most people find this hard to believe, there is sufficient evidence that inactivity actually kills more people per year than smoking.  These numbers would be alarming in any case, but in Canada they particularly hit home: the average Canadian adult spends 50-70 percent of his/her daily life sitting, and roughly another 30 percent sleeping.  In fact, according to Statistics Canada, only 15 percent of adults and 7 percent of children meet the minimum recommended daily physical activity guidelines.  There are several different sets of recommendations that have been put forward over the past five years:

• The Canadian Government recommends 30-60 minutes of moderate intensity exercise per day
• The American Government recommends 250 minutes of moderate intensity exercise, or 125 minutes of intense exercise per week.
• The American College of Sports Medicine (ACSM) recommends 30 minutes of moderate intensity exercise per day, five days per week.

According to an ACSM position statement, several studies support a dose-response relationship between regular physical activity levels and health outcomes - meaning that greater benefit is accrued with higher amounts of physical activity.   Large-scale epidemiological research has estimated that the volume of physical activity needed to achieve specific health benefits is an energy expenditure of approximately 1000 calories per week of moderate intensity physical activity.  That is to say, about 150 minutes of exercise per week – or about 30 minutes of brisk walking per day - is associated with lower rates of cardiovascular disease and premature mortality. The information we now have regarding the health benefits of regular physical activity is more solid than that of almost any other health intervention.  Nothing else in the public health arena parallels the protective nature of exercise – at least equivalent to that of not smoking.  The Public Health Agency of Canada notes that physical activity appears to reduce the risk of more than 25 chronic conditions, including:

•   Coronary heart disease
•   Stroke
•   Hypertension
•   Breast cancer
•   Colon cancer
•   Type 2 diabetes
•   Osteoporosis
•   Depression and anxiety

Regular exercise is good for both pregnant mothers and their babies, and maintains functional capacity for older adults as they age (leading to more years of independent living).  It helps brain function, resulting in the development of more neurons.  It increases brain volume in the elderly, staving off cognitive decline.  In 2009, England’s chief medical officer stated that the benefits of regular physical activity for health, longevity, and well-being “easily surpass the effectiveness of any drugs or other medical treatment”.  Recent research from Brigham and Women’s Hospital and the National Cancer Institute, published in the online journal PLOS Medicine, found that:

•  Low amounts of activity - such as 75 minutes of walking per week - resulted in a gain of 1.8 years of life, compared with no activity.
• At least 150 minutes of activity per week resulted in a gain of 3.4-4.5 years of life.
• Being active in addition to having a normal weight was associated with an extra life expectancy of 7.2 years.

Based on the emergence of incontrovertible research over the past 15 years, we know that the most powerful mechanism for protecting our health and improving longevity is to walk at least 30 minutes a day five times a week. Even better is walking or biking up hills, or slow running.  Go for it!