Four Common Misconceptions About Exercise

One of the most important things to understand about exercise is that it will not help you lose weight. Many people try to exercise away a bad diet. Unfortunately, we do not burn enough calories solely through exercise to lose weight. When you consider it takes 3,500 calories to lose 1 pound, we would have to exercise several hours per day without changing our diet. To burn 100 calories you would have to walk about 1 mile, which means you would have to walk 35 miles each week just to lose 1 pound. That seems crazy, right?

Unfortunately, it is true. So this doesn’t mean you shouldn’t exercise when you are trying to lose weight. The goal of the exercise is weight maintenance. There are certainly going to be days where you may consume an extra 100-300 calories. The goal is for each exercise session to counter the excess calories to avoid weight regain. We often get caught up and only associate exercise with weight loss. We need to remember all the other many health benefits of exercise. For example, improved blood pressure, blood sugars/insulin sensitivity, cholesterol, and joint pains, as well as better sleep and mood.

Fat Burning Zone and Cardio Training Zone

A common belief in the exercise world is that low-intensity aerobic training will allow your body to use more fat as an energy source, in return accelerating the loss of body fat. This misunderstanding is known as the “fat burning zone”. Have you ever wondered what the difference is between the fat burning zone and cardio training zone when you get on a piece of cardiovascular equipment? Treadmills, ellipticals, and stationary bicycles with heart rate monitors often display these zones.

If you have come into contact with these machines you have found that the fat burning zone allows you to work at a lower intensity compared to the cardio training zone. How is it possible that you burn more fat at a lower intensity of exercise? The concept is that at a lower intensity of exercise we burn a greater percentage of fat relative to the total amount of calories expended. At high intensity cardio (cardio training zone), we expend more total calories compared to the fat burning zone. This means that we expend a greater amount of fat in the cardio training zone than the fat burning zone.

Take a look at the graph shown. The x-axis represents % VO2max. In other words, this demonstrates how hard you are working during an exercise bout. The cardio training zone would fall between 50 and 80%. The fat burning zone would fall below 50%. The y-axis represents the percentage of calories you are expending from carbohydrate and fat. The graph demonstrates that as exercise intensity increases, our body shifts towards the use of carbohydrate for energy rather than fat.

Powers, S.K. & Howley, E.T. (2007). Exercise physiology: theory and
application to fitness and performance. New York, NY: McGraw-Hill.

Let’s do the math. You use the treadmill for 60 minutes. You stay within the target heart rate that correlates to the fat burning zone. You burn a total of 200 calories. About 50 percent of those calories will be fat. Fifty percent of 200 is 100. You've burned 100 calories of fat.

On another day you use the treadmill again, but exercise in the cardio training zone. Maybe you are walking faster or have a greater incline than the previous day. Your breathing rate is increased. After 60 minutes, you burn a total of 300 calories. In the cardio training zone, approximately 40 percent of the calories burned will be fat. However, forty percent of 300 calories is 120. You’ve burned 20 more calories in the cardio training zone than the fat burning zone. So the next time you step on a piece of cardiovascular equipment with the fat burning zone and cardio training zone you will be more knowledgeable about the differences between the two. Don’t let the name of the different heart rate zones fool you.

Strength training and toning up

One of the biggest misconceptions about exercise in regards to weight loss is that strength training will make an individual gain weight. People often say they would rather “tone up” rather than “bulk up.” What is the difference between these two terms? When most people say they want to “tone up,” typically this means they want to become leaner. They want to lose fat and add a little muscle definition.

On the other hand, more often men want to “bulk up” or add muscle mass. When you hear “bulk up,” you may envision body builders and football players. While cardiovascular exercise is essential, strength training plays an important role as well. It is your lean body mass, the muscle tissue underneath your body fat that burns calories throughout the entire twenty-four hours of each day.

The more muscle mass you have, the more calories you burn at rest.

Individuals can lose muscle mass through physical inactivity and aging. On average, after age 50 years, strength decreases fifteen percent per decade up to age 70 years. After age 70 years, strength decreases 30% per decade. This loss of strength is related to the loss of muscle tissue. The saying “use it or lose it” can be applied to this concept. If we aren’t including strength training in our exercise program, then we are not increasing our resting metabolic rate.

Unfortunately, aerobic activity only increases our resting metabolic rate for a couple hours after exercise if the session was strenuous enough. Strength training can increase your resting metabolic rate permanently. You can use resistance bands, free weights, weight machines, as well as your own body weight for strength training.

When starting, it is important that you choose to lift heavier weights providing greater resistance performing fewer repetitions (10-12 reps). This means that on the last couple of repetitions your muscles are fatiguing. If you could have lifted that weight five more times, then it is time to go up in weight or resistance. It takes approximately eight weeks for your muscles to hypertrophy with a consistent program.

Make sure you choose at least one exercise for each major muscle group. This includes biceps, triceps, chest, back, shoulders, quadriceps, hamstrings, calves, and glutes. It’s not fair to focus all your attention on just your chest or legs. We need to make sure every muscle is trained to prevent musculoskeletal imbalances. Strength training should be completed two to three times per week on non-consecutive days to have significant gains in muscle mass. Remember, aerobic activity and strength training should both be included in your exercise program for long-term weight loss and weight management success.

Spot reduction exercises

For many years, and to this day, the idea of spot reduction is believed by many. “I am going to do 200 crunches and sit-ups a night and loose abdominal fat”. Unfortunately this is false. We are not able to alter specific areas of our bodies by just targeting the area of interest alone. Losing belly fat requires a combination of things such as correct nutritional intake along with cardio and resistance training.

All three aspects just mentioned are equally important. Research has shown that weight training actually burns a substantial amount of fat. An increase in muscle tissue results in an increase in calories expended. As far as cardiovascular training, alternating between intervals of low and high-intensity bouts of exercise has shown to speed up metabolism as well. Lastly, the best exercise routine will get you nowhere when it comes to weight loss without considering nutrition as well. Again, a poor diet plus a great exercise routine will not show results.  Good nutrition and a solid, consistent exercise routine are the habits for long-term health and well-being.

ABOUT THE AUTHOR Kathryn Randall is the full time exercise specialist at Carolinas Weight Management. She graduated with a Bachelor's of Science degree in Exercise and Sports Science from Meredith College and a Master’s of Science degree in Clinical Exercise Physiology from the University of North Carolina at Charlotte. Kathryn is a Certified Exercise Physiologist by the American College of Sports Medicine. Kathryn leads the UNCC Kinesiology intern program at the Center.

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