Most of us have marveled at the speed of elite athletes—cyclists, sprinters, swimmers—but what we’re really admiring is their VO2 max—the best indicators of aerobic fitness. It’s what enables them to go so far so fast.
VO2 max, also called maximal oxygen uptake, is a measure of how much oxygen your muscles can extract from your red blood cells during your highest level of physical exertion. The more oxygen your muscles get, the faster and farther you can bike, run, swim and more.
This may seem like more information than you need, unless you plan to go for the gold. But the data collected from a VO2 max test can help make your workouts more efficient and beneficial. What’s more, you’ll gain invaluable insight into what might be keeping you from reaching your everyday fitness and weight loss goals—why your workouts aren’t working for you.
VO2 Max: Your Body’s Aerobic Horsepower
Here’s what happens when you physically exert yourself: your heart beats faster to bring oxygen to your muscles, then your body uses that oxygen to burn fat and carbohydrates (glucose), which, in turn, creates energy in the form of a compound known as ATP (adenosine triphosphate). Simply put, it’s this energy that allows your muscles to contract and do work.
VO2 maximum can be simply defined as your body’s ability to consume oxygen. The more oxygen you can burn the better. Why is VO2 max considered the Holy Grail of information to an exercise physiologist? There are four big reasons:
- Wellness Aerobic fitness (VO2 max) is a very important predictor of your overall health.
- Efficiency For most people exercise efficiency is equal to the number of calories you burn during that activity. When we burn one liter of oxygen we burn five calories of fuel,” says Mike Siemens, M.S., an exercise physiologist at Canyon Ranch in Tucson. “So the goal for exercise efficiency is to burn the most oxygen—which means have the highest VO2 maximum you can possibly have.” Highly fit people might be able to burn three to four liters of oxygen per minute while working out, which means 15 to 20 calories per minute. Moderately fit individuals might only burn one to one and a half liters of oxygen per minute and therefore only be able to burn five to seven calories per minute during exercise.
- Enjoyment of movement When we are in poor aerobic condition exercise is not much fun because our muscles burn with lactic acid and we always feel short of breath. You can make exercise more enjoyable by improving your VO2 maximum to the best it can be.
If you’re looking to lose weight, you can benefit from knowing your VO2 max, too. Most people who struggle with fat loss have relatively low aerobic fitness levels (low V02 maximum). To improve your calorie burning efficiency you need to improve your VO2 maximum.
How to Determine Your VO2 Max
A VO2 max test is quite simple, but it requires some sophisticated equipment and someone who knows how to operate it. This is where a good exercise physiologist with a metabolic analyzer can help you. They can be found in some gyms, and most college or at a university exercise physiology testing laboratories.
During the test you will wear a mask over your nose and mouth. This mask allows you to inhale all the air you desire and allows for the equipment to sample your exhaled air. You’ll also wear a heart rate monitor and a portable device called a metabolic analyzer, which will analyze each breath you exhale for how much oxygen you are burning and how much carbon dioxide you are expiring. From this information your exercise physiologist can determine your current aerobic fitness level (VO2 max), accurate calorie burning at any given heart rate, your anaerobic threshold and your optimal exercise heart rates for fat burning, calorie burning and aerobic fitness improvement.
The test can be done on any piece of cardiovascular equipment you are most comfortable using (treadmill, bike, elliptical). Every two minutes your exercise physiologist will increase your work level until you reach 90 to 95 percent of your maximum effort. The ideal test duration is 12 to 18 minutes.
VO2 max is usually expressed relative to body weight because oxygen and energy needs are different for people of different sizes. The number, or your score, will read in milliliters of oxygen per kilogram of body weight per minute. To give you some perspective, top endurance athletes, such as marathon runners, usually score above 70 ml02/kg/min. Aerobic fitness levels of reasonably fit 40 to 50 year olds might be 35 to 45 ml02/kg/min. A VO2 max score below 25 means your aerobic fitness level (and calorie burning ability) is in need of improvement.
A VO2 max test pinpoints your aerobic fitness level and your anaerobic threshold, and it reveals your optimal exercise heart rates (depending on your goal, or goals, for a particular workout) and how many calories you burn per minute at each of them. With this information, your exercise physiologist can create a targeted, customized exercise program that will help you improve endurance and pace, identify your ideal level of exercise intensity for weight loss and more.
How to Increase Your VO2 Max
By improving your VO2 max, you reap all of those great rewards listed above:
- Improved wellness
- More efficient calorie burning
- Improved performance
- Greater enjoyment of movement
Experts suspect that up to 50 percent of your VO2 max potential is determined by your genes. That means the other 50 percent can be influenced by how you work out—specifically, the duration, frequency and intensity of your sessions. That doesn’t mean you have to log marathon cardio sessions every time you lace up your sneakers, or that you need to do all of your workouts at maximum effort—by mixing in a couple of longer sessions with more intense sessions each week, you will strengthen your heart, improve how efficiently oxygen is delivered throughout your body, and improve your muscles’ ability to use it.
One of the best ways to reach your aerobic fitness potential is to do interval training, alternating between one to three minutes of moderate intensity work and one to three minutes of higher intensity activity. Here are a couple of examples you can try:
- Warm up for five to 10 minutes with easy jogging. Run for 30 seconds at a slightly uncomfortable intensity, or about 85 percent to 95 percent of your maximum heart rate. Then jog or walk for 30 seconds to recover to 65 percent to 70 percent of maximum heart rate. Repeat 10 to 20 times. Cool down with easy jogging for five to 10 minutes.
- Warm up for five to 10 minutes with easy effort (bike, elliptical or treadmill).
- Push yourself at a high intensity (80 percent to 95 percent of your maximum heart rate) for two minutes.
- Recover with two to three minutes at 40 percent to 70 percent of your maximum heart rate.
- Repeat five to eight or more times.
- Cool down with easy work for five to 10 minutes.
Talk to your trainer or exercise physiologist about VO2 maximum or exercise metabolism testing. You will find this information very important and useful when creating the exercise program that will help you achieve your dreams and goals.