The ink has barely dried on a new position statement from The American College of Sports Medicine (ACSM). As of February 2009, based on a meta-analysis of research on exercise and weight loss, the ACSM is clarifying some key points between how much exercise will result in weight loss, and how much is involved for weight maintenance once that weight has been lost.
In 2007, the ACSM upgraded their previous recommendations from 1995. Now, only two years later, those recommendations are being upgraded again, this time with a specific focus on weight loss. The current 2009 recommendations are as follows:
• 150-250 minutes per week of moderate-intensity physical activity provides only modest weight loss
• More than 250 minutes per week of moderate-intensity physical activity provides clinically significant weight loss
• Dietary restrictions in combination with greater than 250 minutes of exercise per week will result in even greater weight loss
• Greater than 250 minutes of moderate intensity physical activity may be required to maintain weight re-gain (assuming calorie restrictions have been lifted BUT energy from eating does not return to an excess intake above that required from resting metabolism, activities of daily life, and 250 minutes per week of exercise).
Two-hundred fifty minutes per week is the equivalent of 4 hours and 10 minutes of activity. This results in a target of 50 minutes, 5 days per week for people who prefer to take 2 days off per week.
Any activity where you elevate your heart rate and hold it elevated counts towards the 4 hours and 10 minutes. Moderate intensity has been defined in previous publications as 75% of actual maximum heart rate, also known as the rate at which you can talk but, not in full sentences without having to take a breath.
I say actual maximum heart rate because there can be a plus or minus 30 beat difference per individual from the referenced norms on standard heart rate charts. For this reason, I recommend using the talk test mentioned above over the heart rate charts. Better yet, you can determine your own individual heart rate zones if you work with a certified personal trainer or coach, who can do a simple field test to determine your heart rate numbers for moderate intensity exercise.
The exercise does not have to be done all at the same time on any given day, although if your schedule permits and you prefer to do it all at the same time, great! The exercise can be broken up into segments throughout a given day BUT the minimum is 10 minutes at a time.
Activities that count towards weight loss exercise include formal exercise like treadmill walking/jogging, biking, swimming, elliptical trainers and upper body ergometers. However, daily activities such as shoveling snow, mowing the lawn, vacuuming, sweeping and walking the dog can also count towards weight loss exercise IF they are sustained at a heart rate that is 75% of your actual maximum AND you sustain the activity for a minimum of 10 minutes without stopping.
What this means is that carrying the laundry up and down stairs (I get this one a lot from clients!) does NOT count because it isn't performed without stopping for 10 minutes straight. It also means that generally cleaning the house or painting a room does not count either because the heart rate is probably not at the 75% intensity even though the activity may last longer than 10 minutes at a time. And walking the dog may or may not count depending on the bladder of your pet!
The above activities are included as the activities of daily living and they do burn calories. But, there is a certain amount of calories that are expected to be burned in any given day. This is generally calculated to be approximately 30% of your resting metabolism. Your resting metabolism is the amount of energy required to keep you alive without any physical movement. In other words, if you were in bed just surviving. The exercise amounts necessary for weight loss must be above and beyond activities of everyday life.
The 250 hours of exercise is not a maximum. The guidelines suggest the 250 hours as a minimum and doing more is highly recommended, although the 250 has been found to be effective for weight loss. So don't think that doing more means you are becoming an excessive compulsive exerciser. This is an issue for some people but many, many more people are victim to too little exercise.
Finally, the 250 hours of recommended exercise is exclusively cardiovascular exercise. The guidelines also includes a recommendation for strength training, which is not included in the 250 hours. The recommendation for this is 8-10 exercises performed for 8-12 repetitions of each exercise done 2 times per week.
Strength training exercise has not been found to result in significant weight loss, but has been found to result in an increase in fat-free weight and that has been correlated with reductions in health risk factors. Fat-free weight is also believed to help maintain a higher resting metabolic rate, but generally not significant enough to result in weight loss in isolation of dietary restrictions and cardiovascular exercise.
Bottom line: In order to lose excess body weight, a minimum of 250 hours of sustained moderate activity must be performed each week with the addition of 2 days of strength training AND calorie restriction below that of what is being burned.
Judy Torel is a USAT coach, personal trainer, nutrition consultant and psychotherapist. She conducts online services through her website www.judytorel.com. Her office is located in Planet Fitness, Loudonville. She is also a competing triathlete who is currently training for Ironman, Florida. She can be reached at 469.0815 or firstname.lastname@example.org.