Filed under: Cardio
You’ve probably seen those colorful charts on exercise machines at the gym, showing your ideal heart rate zone for optimal fat burn. Is this “zone” the best way to burn fat?
The concept of the “fat-burning zone” might not be entirely true. Many people assume that in order to burn fat, they must keep their heart rate within the defined range. This can be misleading for a few reasons. First, people’s heart rates are very different, making it difficult to generalize recommendations from a fixed chart. Second, your body burns two main sources of energy during exercise: fats and carbohydrates. (Protein is an energy source, but it’s only used in very small amounts.) For any given heart rate, your body will burn both carbohydrates and fats; however, the proportion of each will vary. Low-intensity exercises (lower heart rate) with a longer duration (30 minutes or more) mostly rely on fat for energy. So, there’s a zone in which a higher proportion of fat is being used for energy, but that doesn’t necessarily mean more fat is being burned. Your body actually gets most of its energy from fat during rest. In theory, your ultimate “fat-burning zone” is in your living room: you lying on your couch, binge-watching your favorite new series.
So, how do you burn more fat? High-intensity exercises actually burn the most fat due to the higher overall energy (caloric) expenditure. Interval training is a great way to boost the intensity of your workout, and you get that “afterburn” effect. Fitness level also is a factor. Fitter people’s bodies tend to utilize more fats than carbohydrates.
If you’re training for endurance activities, the “fat-burning zone” on the exercise machines might be the “right zone” for you. To burn even more fat, you ultimately need to burn more overall calories. High-intensity workouts are a challenging and efficient way to help reach your goal.
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Monitoring your heart rate is a useful tool you can learn to use to guide your training and make sure you’re getting the most out of your workouts. It can help make sure you’re pushing hard on interval days (vigorous exercise) and taking it easy on recovery days (light exercise). But what do words such as “light,” “moderate,” and “vigorous” mean when it comes to exercise?
You can determine your exercise intensity using your maximum and resting heart rates. Then you can use the Heart Rate Reserve (HRR) method to calculate your Target Heart Rate (THR) to determine what range your heart rate should be in for your desired exercise intensity. We provide a step-by-step process you can follow. Read more here.
Reports estimate that one of every four deaths is attributed to heart disease. Cardiorespiratory (aerobic) activities such as jogging, cycling, and swimming directly improve the function of the heart, which decreases the risk of coronary artery disease, high cholesterol, high blood pressure, stroke, and type II diabetes. Aerobic fitness is important enough that all active-duty service members must complete an aerobic fitness assessment, such as a maximal effort timed run, as part of their annual physical fitness test.
To delve a little deeper about the changes your heart, lungs, and blood vessels undergo when you improve your aerobic fitness, read on. One important change that occurs is that your heart’s “stroke volume”—the amount of blood the heart pumps out with each beat—increases. This comes from an increase in your heart’s strength and ability to hold a greater amount of blood. This in turn reduces your heart rate (HR) both at rest and at all levels of exercise. In fact, with consistent training, your resting HR could likely decrease as much as eight to10 beats per minute. That’s about 5 million fewer heartbeats in a year! Simply put, aerobic training means your heart has to do less work to get your job done.
Changes also occur to your blood and blood vessels with aerobic fitness. Your blood vessels increase in diameter and are better able to expand and constrict. This allows blood to move through your blood vessels with less resistance, reducing your blood pressure. And what happens to your blood? The levels of plasma (the liquid portion of the blood), red blood cells, and hemoglobin all increase, which means that your blood can carry more oxygen.
Altogether, the physiological changes mentioned here should make it easy to see why aerobic exercise is so important. If you want to learn more about how to get started improving your cardiorespiratory health through exercise, visit these Performance Strategies from HPRC.
Deployments, injuries, transitions—just a few of the many things that can interfere with your normal exercise routine. Too long a break and your cardiovascular—or aerobic—fitness may suffer. For optimal performance, however, getting your heart and lungs back in action is critical. If you’ve been away from your routine for a while, start slowly and gradually increase intensity and duration. Be patient and stick with a routine, even on days you don’t feel like it. Mix up your routine when you’re able with different types of aerobic exercise such as biking, running, swimming, and rowing. For help planning your comeback, check out HPRC’s Performance Strategies for Rebuilding Cardiovascular Fitness. If you’d like to learn more about aerobic conditioning specifically for the PRT/PFT, read part 1 of our training series.
Getting enough exercise is important to everyone’s mental and physical health in order to achieve optimal performance. Active-duty Warfighters usually get enough exercise in the course of their mission, but for the rest of us in the sphere of the military—family members, desk warriors, and the like—it can take more effort, so sometimes it’s helpful to review.
The Physical Activity Guidelines for Americans recommend that:
Aerobic exercise: For health benefits, adults should do at least 2.5 hours (or 150 minutes) a week of moderate-intensity exercise, or 75 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity exercise.
- For the greatest health benefits, adults should do aerobic exercise of moderate intensity for five hours, or 300 minutes, weekly, or 2.5 hours or 150 minutes of vigorous-intensity aerobic exercise, or an equivalent combination of both.
- Do aerobic activity for at least 10 minutes at a time, preferably spread throughout the week.
- Don’t know how to gauge your exercise intensity? Check out ACSM’s video on aerobic intensity or the description from the Centers for Disease Control and Prevention (CDC). Examples of moderate-intensity activities include walking at three miles an hour, water aerobics, biking less than 10 mph, and gardening; vigorous-intensity activities include jogging or running, swimming laps, singles tennis, biking more than 10 mph, jumping rope, and hiking. Another method for determining exercise intensity is to keep track of your heart rate; use this explanation from CDC for how to determine your target heart rate for various activity levels.
- A general guideline for time spent exercising is that two minutes of moderate-intensity activity is equal to one minute of vigorous-intensity activity.
- For exercise ideas, check out ACSM’s video on types of aerobic exercise and/or HPRC’s Performance Strategies on Rebuilding Cardiovascular Fitness.
Strength training: Do muscle-strengthening exercises (resistance of moderate or high intensity) that involve all major muscle groups at least twice a week.
- For muscle strengthening, try doing 8–12 repetitions for each type of exercise. Do at least one set, but try for two or three sets for more benefits, at least twice a week!
- Be sure to work out your major muscle groups, including legs, hips, back, abdomen, chest, shoulders, and arms.
- For some muscle strengthening ideas, check out ACSM’s handout on basic strength-training exercises to do with just your bodyweight or their video of some basic moves you can do at home. Or try ACE’s step-by-step workouts for a total body workout, a 30-minute lunch workout, total body conditioning for parents, and many more. Also, check out HPRC’s Performance Strategies on improving your Muscle Strength as well as your Core Strength!
Finally, remember to stretch after your workouts. For some basic ideas on stretching, check out ACSM’s pictorial sheet, their video on stretching basics, or HPRC’s Performance Strategies to “Improve your flexibility.”