VO2 Testing and Training: The down and dirty

Contributed by Dr. Steven T. Devor – Director of Performance Physiology for MIT and OhioHealth, and Associate Professor of Exercise Physiology, Department of Human Sciences, and Department of Physiology and Cell Biology, The Ohio State University

What is your max heart rate? You may have seen the large signs at your gym, or Googled “max heart rate” and found an equation that claims to give you your max heart rate. However, these are all based on averages across HUGE populations. The only way to truly find your max heart rate (MHR) is to have VO₂ max test performed in a clinical setting.

Why is it important to know your true MHR? Without knowing your MHR, you can’t know what your heart rate zones are. So, if you look at the MIT schedule and it suggests that you run in high zone 2 on Saturday, without knowing your true MHR (and consequently each of your heart rate zones), you will have no way of determining whether or not you’re actually in high zone 2. Many people have MHRs well below the average and many people have MRH well above the average, so it’s important to know your true number.

What determines your MHR? Your MHR is determined primarily by age and genetics. Your fitness level has NO bearing on your MHR. Whether you are completely sedentary or in the best shape of your life, your MHR changes only as you age. What does change as you become more fit is your VO2 max, or your body’s maximum capacity to transport and use oxygen during maximum effort.

Heart Rate Training Zones

Active Recovery: Easy aerobic activity
Aerobic: Long distance training runs
Tempo: Comfortable hard (anaerobic threshold is at the top)
Interval: Introducing anaerobic intensity
Highest Intensity Interval: High anaerobic effort, use with care to avoid overuse injuries

Details on Heart Rate Guided Training

Most endurance athletes spend nearly all their training time in Zone 3. This is what we refer to as “Training never, never land.” Heart Rate Zone 3 is not hard enough to become race fit, but it’s not easy enough to allow your body to recover from a hard workout. When an athlete spends most of their time in Zone 3, their interval workouts will suffer because they haven’t given their body the appropriate time to recover. It can also lead to overuse injuries.

Instead, you want there to be an ebb and flow to your training plan. Look at the two images from an MIT plan below. Wednesday, the schedule has 6.5 miles in Heart Rate Zone 4-5. The next day, the schedule calls for 3 miles in Zone 3, to allow for recovery. In the second image, you’ll see that after a particularly hard interval workout (10 miles), the schedule calls for a rest day to allow for even more recovery. Your true fitness gains come after the long or hard workouts, while you allow your body to repair and build.

Learn your resting heart rate

Throughout any training season, you might go through periods where you feel fatigued or run down. How can you tell if you are flirting with overtraining and need to take a rest day, or whether you just didn’t get enough sleep the night before and can train through it? The answer is in your resting heart rate. If your resting heart rate is elevated, this is the best estimate of body fatigue.

Find your resting heart rate by taking your heart rate four or five times over the course of a couple of weeks. Take your heart rate as soon as you wake up (before you stand up to turn off the alarm or go to the bathroom). Average those four to five data points and you have your resting heart rate.

Now, get in the habit of checking in on yourself when you wake up in the morning. If you start to find your heart rate is elevated more than a couple of beats above average, take it easy. If you have an interval workout scheduled for that day, at the minimum, go for an easy run (or walk, bike, or swim) instead. Taking the day off entirely might also be a good idea.

If you can stay in tune with your body, you’ll be taking great strides towards keeping your training on track.