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Monday, June 21, 2010

Intensity: the key to faster weight loss

If you're trying to lose weight, which about 50% of the American population is doing at any given point, you probably already know that exercise and diet are key. You might not know that just *any* exercise will not necessarily get your the results you want.

Numerous studies have shown that the old way of thinking about cardiovascular exercise - slow, sustained activity at 65% of max heart rate for optimum effectiveness - cannot hold a candle to interval training, which mixes very high intensity with lower intensity recovery periods. The problem with high intensity interval training is that not everyone can do it. However, more people can do it than think they can. Even if you are significantly overweight, as long as you don't have uncontrolled high blood pressure, heart disease or some other health problem that would contraindicate vigorous exercise, you can probably work much harder than you think you can. The reality shows such as Biggest Loser are proving that even very obese people can work much harder and longer than previously thought. Do ask your doctor if you are at all concerned about your ability to perform intense exercise, but if your health is good other than your extra weight, it's probably time to try a more intense approach to exercise.

Another piece of the older thinking about intensity is the max heart rate calculation. According to the equation, your max heart rate should equal 220 - your age in years. For example, if you are 50 years old, that would make your max heart rate 170. The problem with this is that everyone is different, and the research has found that everyone is different enough regarding max heart rate that the equation means very little. I think it's a great idea to keep track of your heart rate while you exercise, but only as a tool to help you keep your intensity high. The combination of old thinking about the "fat-burn zone" existing at 65% of the maximum heart rate and fears of heart attacks, etc, seem to combine to make people want to keep their heart rate low and panic when it rises. A higher heart rate in most cases is a good thing! It means you are working harder and burning more calories overall, and thus more fat than if you were to work at the lower rate for sustained periods of time.

Rather than focusing on heart rate, fitness professionals are turning more and more on the Rate of Perceived Exertion (RPE). On a scale of 1-10, 1 being lying in bed relaxing and 10 being afraid of impending death due to exertion, how do you feel when you exercise? If the answer is generally between 1 and 5, you would do well to get in at least a fewer intervals that bring you up to 7, 8 or 9.

Higher intensity not only increases your calorie burn during exercise, but also for hours afterward. This is known as the afterburn effect. Slow, sustained exercise has very little afterburn. High intensity exercise has a considerable afterburn, meaning you will keep burning calories at an increased rate even hours after your workout ends. This makes higher intensity much more effective than slow, sustained exercise by a LOT.

Basically, the rule of thumb is this. If your body is comfortable, it will not change. Your body generally wants to stay in the state it's in - it got into that state for a reason. Higher intensity exercise is not very comfortable. Because the body is working harder than normal, it will respond by changing; dropping body fat and building lean muscle (as long as you are getting proper nutrition and not a starvation diet). If this is what you want, you're going to have to push it.

Again, ask your doctor first if you have any cause for concern about high intensity exercises. Try starting with one of these 1-3 times per week and see your body begin to respond:

Major Muscle Training Intervals:

Warm up for 5 minutes by walking or jogging.

Run or Jog for 1 minute.
Sprint (run as fast as you can) for 15 seconds.
Perform 10 pushups, 10 situps or crunches and 10 squats.
Repeat 5-8 times.

Cool down for about 5 minutes by walking or jogging slowly. Stretch when done.

Cardio Machine Intervals: (bike, elliptical, treadmill, etc.)

Warm up for 5 minutes with a RPE (rate of perceived exertion) of about 3.

Go for two minutes with a RPE of around 5.
Go for 30 seconds with a RPE of around 7-9.
Repeat 6-10 times. (Increase the number of intervals as you become more fit).

Cool down for about 5 minutes by walking or jogging slowly. Stretch when done.

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