Inactivity More Deadly Than Obesity, New Study Finds

Everyone needs to exercise at least a little every day, concludes a study involving 334,000 men and women published in the American Journal of Clinical Nutrition.

Heading up the massive study for the  European Prospective Investigation into Cancer and Nutrition are Dr Ulf Ekelund (University of Cambridge, UK), Dr. Heather A Ward (Imperial College London, UK), and a long list of collaborators. "This is a simple message: just a small amount of physical activity each day could have substantial health benefits for people who are physically inactive," Dr Ekelund told the press.

Physical inactivity has long been associated with increased risk of early death, Dr. Ekelund explains. Although physical inactivity contributes to obesity, measured in terms of BMI (body mass index), it is a risk factor independent of BMI, especially in people of normal weight.

The European Prospective Investigation into Cancer and Nutrition (EPIC) Study followed 334, 161 men and women from across Europe from 1992 until 2012. The researchers measured height, weight, and waist circumference every year from 1992 until 2000, and then tracked the participants for another 12 years. Volunteers for the study reported their levels of physical activity to the researchers. During those 12 years, 21,438 participants died.

A Big Difference Between "Inactive" And "Moderately Inactive"

The research team found the greatest difference in death rates between two groups, Europeans who were "inactive" and Europeans who were "moderately inactive." "Inactive" participants in the study reported getting no exercise on the job and getting no exercise in their leisure activities. "Moderately inactive" participants in the study reported getting no exercise at work, but including about 20 minutes of physical activity per day in their daily routines away from the job.

In every weight group, thin or fat, getting at least a little exercise every day made a critical difference in survivability. "Moderately inactive" people reduced their risk of death by 16 to 30 prtvrny. The amount of exercise needed to make a difference is roughly enough to burn 90 to 110 calories (kcal) a day. For an obese person, that might be as little as walking half a kilometer (1/3 of a mile) a day. For a normal-weight person, that might be walking 2 kilometers (1-1/4 miles) or so. Other light exercise also confers benefits. Of course, other forms of exercise also count, and a routine including other aerobic activities, physical agility activities, resistance exercise, and sport is ideal.

See Also: Exercise In Prevention Of Weight Regaining After Weight Loss

Implications For Medical Practice

The authors of the study state that encouraging exercise, even more than weight loss, should be a top priority of doctors. Says Professor Nick Wareham, one of the contributors to the paper, “Helping people to lose weight can be a real challenge, and whilst we should continue to aim at reducing population levels of obesity, public health interventions that encourage people to make small but achievable changes in physical activity can have significant health benefits and may be easier to achieve and maintain.” 

It Isn't Enough To Be Thin If You Never Exercise

The analysis of data from over 330,000 people for 20 years found that getting more exercise did not predict whether people would maintain the same weight, gain weight, or lose weight. The authors of the study note that thin people who never exercise are at greater risk of early death from cardiovascular disease, cancer, and other ills than obese people who do. What is it about physical inactivity that increases the risk of death even more than obesity?

• Physically inactive people are at greater risk for deep-vein thrombosis, the formation of blood clots in veins in the legs that can travel to the heart and brain.
• Physically inactive people are less able to literal "fight or flight" situations, and may be more likely to succumb to accidents or intentional injury.
• Physically inactive people do not put stress on their bones, so their bones renew and remodel themselves less frequently. They are more likely to suffer fractures and breaks when they fall, and breaks of certain bones (the hips, the skull) are associated with increased risk of death.
• Physically inactive people are more prone to feelings of anxiety and depression.
• Physically inactive people are at greater risk for development of diseases that become confining, such as lower back pain, which increase the effects of their inactive lifestyle.
• Physically inactive people are at greater risk for certain kinds of cancer, notably breast cancer and colon cancer, and have more difficulties dealing with complications of cancer treatment such as lymphedema.

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Moreover, the data revealed that while exercise seems to prevent numerous physical ills, it does not necessarily prevent weight gain.

• Some people compensate for exercise by eating more. This means they get the cardiovascular benefits of exercise without getting the full range of metabolic benefits of exercise. People who try to lose weight by exercising more typically gain weight, less than a kilogram (2 pounds) or so, in the form of muscle.
• Type 2 diabetes can make exercise tricky. Diabetics who are not used to exercising on a regular basis may take too much insulin or fail to eat enough carbohydrates to prevent crashing blood sugars during their workout. The natural response to falling blood sugars is to eat ravenously, and to consume more calories than are burned in the workout. The solution is to do short sessions of mild exercise, testing blood sugar levels before and after, slowly building up to full workouts when blood sugar responses are well known.
• Obesity has a genetic component (as do habits for getting exercise). Genetic factors may amplify the effects of choices that have smaller impact on other people who do not have the gene.

Ideally, everyone should exercise, maintain a "normal" weight, and avoid smoking. If you can only accomplish one of these three goals, however, exercise. Physical activity is even more important to health than weight control and avoiding tobacco.