There is little argument that being overweight is associated with increased risk for a number of chronic diseases. We have been hearing this message for so long that the urgency of it has become diluted. Although it's easy to tune out this message, facts are facts: The American College of Sports Medicine's (ACSM) position stand published in February of 2009 has sounded an alarm. Unfortunately, scientific alarms are mere squeaks compared to the roar of the messages we get that promote unhealthy lifestyles. We need science to get louder.
The ACSM originally published their position stand, "Appropriate Physical Activity Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults," in 2001, and it has set the bar for how much exercise we need and why. The bottom line of the 2009 update is that we need more exercise than has been previously recommended.
Overweight and obesity:
- Are defined as a body mass index (BMI) of 25 to 29.9 kg/m and 30 kg/m or greater, respectively
- Are exhibited by about 66.3% of adults in the US
- Are associated with heart disease, hypertension, diabetes, some cancers, as well as psychosocial and economic difficulties
- Are estimated to cost the US over $117 billion annually in treatment for weight reduction
There are few health issues this critical that affect the majority of our population. This must be turned around on an individual level, and as personal fitness trainers and athletic trainers agree, the only way a person can lose weight is by creating a calorie deficit either by eating fewer calories or by burning more calories. All scientifically sound recommendations promote a combination of both to achieve weight loss. Any promotions telling you anything different (weight loss in pills/powders/creams/or anything while you sleep) are misleading and should be condemned.
Focusing on the exercise portion of the weight loss equation, decades of research in personal fitness training have yielded the following recommendation, taken directly out of the 2009 position stand:
"ACSM recommends that adults participate in at least 150 minutes/week of moderate-intensity physical activity to prevent significant weight gain and reduce associated chronic disease risk factors… However, there is a likely dose effect of exercise, with greater weight loss and enhanced prevention of weight regained with doses of exercise that approximate 250–300 min/week of moderate intensity physical activity."
Translation: 30 minutes a day is helpful, but significant weight loss realistically requires about an hour a day minimum (5 days a week). More is better.
Other findings highlighted in this paper are that improvements in chronic disease risk factors (decreased blood pressure, LDL cholesterol, triglycerides, and increased HDL cholesterol and glucose tolerance) have been reported with as little as 2–3% of body weight loss.
The position stand also covers what is recommended for weight maintenance once weight loss is achieved.
- Continued exercise is the best predictor of weight maintenance
- >250 minutes/week of moderate exercise is recommended for weight maintenance
- Most literature indicates "more is better" regarding the amount of exercise needed to prevent weight regain after weight loss
More reckoning
Diabetes is very highly associated with overweight. One in three children born in 2000 will develop diabetes. This number rises to one in two among minorities. We have 23.6 million diabetics in the US now, and this number is expected to rise to 50 million by 2025. Diabetes alone costs the US $174 billion/year, and that number is expected to rise to $351 billion by 2025. The Diabetes Prevention Program study shows that modest weight loss and regular exercise reduced diabetes incidence by 58% and 71%, respectively, in people over 60.
How did this happen?
ACSM's position stand weighs in on this, too. It reminds us that most adults spend most of their time sitting, whether at work or home. This is likely a major cause of the obesity epidemic.
How do we deal?
To an already active person, the recommendation of about an hour of exercise a day probably sounds reasonable. To the majority of our country, this upping of the ante could sound impossible. It's best to approach these recommendations as a set of facts, guideposts, and goals to work towards.
Translating abstract guides for entire populations to individual lives is tricky. If an hour a day is impossible for you, decide what is possible and start there. It's about doing something to better yourself, no matter how small you start.
The point of this article isn't to scold. We already know we need more exercise, and the studies back this up. We need to honestly evaluate our lifestyles and make informed decisions about our levels of physical activity.
If you are or choose to be active, you are on the track to better health. If you are overweight and/or obese, and decide to be inactive, know that it is more likely you'll have negative health and possibly even financial consequences. Make a good decision.
References:
Donnelly, J.E., et al. 2009. Appropriate Physical Activity Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults. American College of Sports Medicine Position Stand. Medicine & Science in Sports and Exercise. 41(2): 459–471.
http://www.cdc.gov/diabetes/pubs/pdf/ndfs_2007.pdf
http://www.cdc.gov/diabetes/statistics/slides/maps_diabetesobesity94.pdf; May 2008
Diabetes: A Roadmap for Change; Media Planet; 2008; www.mediaplanet.com; printed and distributed in the Washington Post, Nov. 2008.
Narayan KM, Boyle J, Thompson T, Sorensen S, Williamson D. Lifetime risk for diabetes mellitus in the United States (abstract 967). Diabetes 2003;52(supplement 1):A225.
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General, Fat, Research, Shape
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