There are many ways to measure if a run is successful. You might look at distance – how many miles you covered. You may assess your pace – how fast (or slow) you ran. You may consider frequency – simply being consistent with your running or training. Or maybe, you say screw all those things and confirm your run a success if you simply felt good. All of these are important ways to analyze your running and training. But there is another tool you can have in your toolbox to measure intensity – how much effort you invest in your workouts: Heart rate training.

Training with a heart rate monitor can help you better understand how hard you’re running, if you’ve recovered adequately between speed work intervals, how fast you’re using up your energy and the overall effort you’re putting forth. The American College of Sports Medicine recommends that we monitor our heart rate during exercise to make sure we’re exerting the right amount of effort based on our abilities.

Knowing your VO₂ max (maximum oxygen consumption) and establishing your heart rate training zones is one way to help ensure we’re adding enough intensity to overload our body without causing over-training or injuries.

Is your head already spinning? I had my VO2 max and heart rate training zones professionally tested last month, and I wanted to share my experience – both as an athlete and a coach. This is a very complex topic, so I will break it down for many of you who may be new to heart rate training. The information I’m sharing comes from the North American Academy of Sport Fitness Professionals and Precision Heart Rate Training by Edmund R. Burke, Ph.D. (a text I highly recommend if you’re thinking about heart rate training).

The Basics

There are a lot of technical terms that can feel a little overwhelming when you begin talking about heart rate training. Let’s review the basics.

VO₂ max: VO₂ max is the maximum amount of oxygen a person can use while exercising. The more oxygen you can consume while exercising (i.e. the higher your VO₂ max), the better your aerobic capacity. My VO2 max for running is 54.9, which falls in the superior category for women age 30-39 (yes, I did a little happy dance when I saw the word “superior”). The best way to determine your VO2 max is with professional testing. Although you don’t necessarily need to know your VO2 max to calculate your heart rate training zones, you will notice how drastically different my zones are based on manual calculation by my maximal heart rate and my professionally diagnosed VO2 max (toward the end of this post).

Resting heart rate: Your resting heart rate is the number of times your heart beats per minute when you’re at rest. The best time to measure it is when you wake up in the morning before getting out of bed. To calculate your resting heart rate, either put on a heart rate monitor or count manually by placing your index finger and middle finger just below the fleshy pocket of skin under your thumb on your wrist. You can either use your heart rate monitor while lying down or count the number of pulses during a 60-second period to determine your resting heart rate. Do the same thing for 5 to 7 days and then take the average. Really fit athletes can have resting heart rates that are less than 50 beats per minute. Mine is around 52 beats per minute.

Maximal heart rate (MHR): Your MHR is the highest number of times your heart can contract (beat) in one minute. Reaching your MHR would occur when you’re running or exercising at an all-out pace. This number is needed to calculate your heart rate training zones. There are 2 ways to determine your MHR.

1. The best way is to get professionally tested at a sports facility or clinic. This typically costs between $100 and $200. The professional will help you put on a heart rate monitor and will also place a mask over your face that is attached to a machine. You will run on a treadmill for typically 7 to 12 minutes until you reach a plateau. Every minute, the technician will increase pace and incline, alternating between the two until failure. I went for 13 minutes. On the bike, you will do the same thing, except you will alternate between pace and gears until failure. I went 7 minutes on the bike. Your professional test will not only yield MHR, but also VO2 max, anaerobic threshold (described below), heart rate training zones and more.

2. If professional testing is not a possibility, you can use the general calculation below:

220 – your age = MHR

Because this equation is just an average, it can vary by 15 beats per minute. Without getting professionally tested, your resulting heart rate zones could be off quite a bit.

Let’s look at my numbers as an example.

My MHR during a professional treadmill test last month for running is 184. If I use the equation above (220 – 32 years old), my MHR is 188. In this case, it is only 4 beats per minute off. One other thing to note is that your MHR is sport specific, meaning your MHR for running may be different for biking. My MHR for the bike is 176. It’s common for your bike MHR to be lower than that for your running.

Your MHR decreases as you age, and females typically have a lower MHR than males.

Anaerobic threshold (AT): Your AT is the point at which you have reached a certain intensity level in your workout when your body can no longer supply enough oxygen to keep up with the demand you’re putting on it. We begin to build up lactic acid. We can typically maintain our heart rate associated with this level of intensity for about an hour. Often during training, we work at our AT for about 3 to 5 minutes during speed workouts and interval training, which can help improve our overall fitness and speed. Anerobic threshold is also referred to as our lactate threshold. My AT for running is 178 and is 169 for biking.

Heart rate training zones: Heart rate training zones are ranges of effort based on your maximal heart rate (MHR). There are typically 4 heart rate training zones (sometimes a fifth that gets into very fast speed work) that correspond with different levels of intensity. To improve or maintain your fitness, the rule of thumb is that you want to train between 50 to 85 percent of your VO2 max or 65 to 90 percent of your MHR.

• Zone 1 (Very light activity/aerobic): 50 to 60 percent of MHR – This is typically associated with daily activities, walking and very easy running, such as recovery runs. It is a good zone for beginning runners and athletes just starting out. In zone 1, our bodies are burning fat.
• Zone 2 (Aerobic): 60 to 70 percent of MHR – Zone 2 exercise helps strengthen your heart. Running in this zone will help you get stronger and increase your endurance, cardiovascular capacity and your heart’s ability to pump blood. This is the range in which most of your easy runs will be done.
• Zone 3 (Fitness/performance training): 70 to 85 percent of MHR – This is the most popular intensity zone for increasing fitness. Running in zone 3 is often categorized by the fastest pace you can maintain while still being able to talk and remain somewhat comfortable. Lactic acid typically doesn’t build up during this zone. Running in zone 3 will help you improve your endurance and, over time, increase the pace you can run at without building up soreness and lactic acid.
• Zone 4 (Improved performance/anerobic – “without oxygen”): 85 to 100 percent of MHR – When you are training in zone 4, you will eventually be running at or near your V02 max or MHR, and you will definitely hit your anaerobic threshold (AT). Your body will no longer be able to take in oxygen while exercising, and training at such a pace will begin to teach your body to train/run harder while metabolizing lactic acid better. Zone 4 is the zone in which you will do all your speed workouts and most of your tempo runs.

To determine your heart rate training zones, simply take your MHR that you calculated above (220 – your age) and multiply by the percentages for each zone to find your ranges. Let’s use my data as an example:

Jesica’s MHR: 184

Zone 1: 50-60 percent of MHR:
184 x 0.50 = 92
184 x 0.60 = 110.4
Jesica’s Zone 1: 92-110
Actual from professional testing: 117-151

Zone 2: 60-70 percent of MHR:
184 x 0.60 = 110.4
184 x 0.70 = 128.8
Jesica’s Zone 2: 110-129
Actual from professional testing: 152-161

Zone 3: 70-85 percent of MHR:
184 x 0.70 = 128.8
184 x 0.85 = 156.4
Jesica’s Zone 3: 129-156
Actual from professional testing: 163-170

Zone 4: 85-100 percent of MHR:
184 x 0.85 = 156.4
184 x 1.0 = 184
Jesica’s Zone 1: 156-184
Actual from professional testing (they have zones 4 and 5): 171-197

Additionally, my professional testing yielded the following guidance for heart rate training based on certain types of runs for my current ability level (yours will be different based on your VO2 max and MHR):

• Recovery run: 142 or below (Zone 1)
• Easy run: 142-155 (Zone 1-2)
• Long run: 151-162 (Zone 2)
• Steady state run (slightly slower than race pace): 157-169 (Zone 2/3)
• Tempo run: 171-182 (Zone 4)
• Speed intervals: 176-190 (Zone 4)
• Hill sprints: 176-196 (Zone 4)

Factors that Can Affect Heart Rate Training
There are several factors that can increase your heart rate during exercise. Here are a few to be mindful of if you begin heart rate training:

• Anxiety or stress
• Heat may increase your heart rate as much as 10 beats per minute during an hour of running (or cycling) from exercising at the same effort in more moderate temperatures.
• Cold temperatures may cause an increase in heart rate if you’re dressed in few layers.
• Dehydration and increased body temperature
• Altitude

Later this month, I’ll be talking about heart rate monitors and some other gadgets and gear that can aid in running with a heart rate monitor and getting used to heart rate training.

Do you use a heart rate monitor during running or exercise? If so, tell us what you think and share your advice. What other tips would you add or offer when it comes to heart rate training for runners or triathletes?