Monthly Archives: September 2011

Does a Workout Give Your Metabolism a Big Boost Afterwards?

 This is something I  have heard before and wondered whether it was true or not. Doing a little internet research and asking an experienced fitness professional made me realize I had opened a large can of worms.

There are a great many factors that determine your metabolism rate, some of which you can control like food intake and amount of exercise and some which you cannot like gender, genetics and body type.

Proper scientific research, or perhaps the lack of it, is full of claims of definitiveness, controversy and contradiction. Which really does not help matters. But after a brief explanation of the science involved I will attempt to answer the burning question. Does a solid workout on the treadmill mean you can hit the Dairy Queen for an extra-large Blizzard on the way home and at least come out even?

The science. Metabolism rate is largely measured in terms of oxygen consumption needed (and therefore calories burned) to perform body functions. It is calculated by looking at your Resting Metabolic Rate (RMR), the Thermic Effect of Food (TEF) and your Physical Activity Energy Expenditure (PAEE).

Your RMR is the number of calories needed to maintain your vital body functions and is usually about 65-75% of your daily calorie expenditure. You do not have much control  over what your RMR is but there is a way to calculate it. www.ksmithwriter.com/mifflin_equation_for_weight_control.html

The TEF is the calories needed to digest, absorb and store the food you eat each day. It accounts for 5-10% of your daily calorie expenditure.

The PAEE is calories burnt during activity. Any activity. From the fidgeting you do looking for the remote in-between the couch cushions to running a marathon. This activity accounts for 20-30% of daily calorie expenditure.

Now remember we are discussing metabolic rate here. Calories taken in verses calories burned is, of course, the crucial equation for fat loss but not exactly what we are looking at in this post. We want to know whether our workout gives us such a boost in metabolism that we do not return to our normal RMR for a long period. As much as 24 hours in some claims.

The answer on the 24 hours seems to be a pretty definite NO. But there is some effect. Sorta. Kinda. If you do the right thing.

Research has found that with cardio exercise…This is a good time to underline that we are talking cardio here as strength training produces a different set of results. But with cardio the intensity but not the duration does seem to slow the body’s return to normal RMR by A COUPLE OF HOURS.

Was does this mean for you? Well if your usual cardio is the treadmill or some jogging it may be time to consider some sprints. A well-thought of workout involves sprinting all out for 30 seconds then jogging or walking (depending on what you can manage) for 90 seconds and repeating that eight times. A sixteen minute cardio workout that kicks your ass with its intensity.

If you like the sound of that then good. But do not drop the duration workouts for intensity ones. It is spending time in the fat-burning zone of your heart rate that really gets to the stored fat. Cyclists and long-distance runners tend to be the leanest athletes for a reason.

If you read all of this post looking for a YES on the extra-large Blizzard sorry it was so long and wordy. You didn’t really think it was going to be there did you? Get the sample size or better yet a yogurt.

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