As a distance runner, you regularly trade information about your runs referring to pace and distance. However, you seldom hear any runner speak about what heart rate they averaged. Heart rate-based training utilizes information given by your heart rate, measured in beats per minute, to determine how hard you are working when training. Your heart rate is a great indicator of intensity. Besides, your heart rate gives you a lot of information that can help you train. 

Here are some of the benefits of heart rate. These aspects can help you optimize your training.

1. What should your recovery runs feel like?
2. What should easy runs feel like?
3. What heart rate determines your work and rest period in a speed workout?
4. What kind of intensity are you running at?
5. Are you working in your aerobic or anaerobic zone?
6. How much fat or carbohydrate are you burning?
7. Your heart rate can tell you if you are going into overtraining
8. It indicates signs of fatigue when you run or race
9. It can guide you on intensity when you train at altitude or in the heat

What are heart rate zones and how do you determine them?

It may be noted that your heart rate is unique to you as a runner and it is influenced by age, gender, genetics, medication (such as beta-blockers), stress, and heat or humidity. Each person has a resting heart rate and a maximum heart rate. 

The resting heart rate is the number of beats per minute (bpm) when you are sitting and resting. The maximum heart rate is the rate at which your heart beats when stretched to the limit. The maximum heart rate can be checked in a clinical setting, when you are made to run on a treadmill with a heart rate monitor strapped to your chest. However, since this is not practical there are empirical guidelines to determine your max HR. 

The most widely used formula is the Fox formula which is 220-your age. However, it is not always accurate as there are variables that affect your heart rate, such as genetics, altitude, gender, body size, and of course, age. There are other alternative formulas that are more accurate, such as the Tanaka formula, which is 208-(0.7 x age).

For heart rate-based training, the range between your resting heart rate and max heart rate is divided into five zones. 

1. Zone 1: 50% to 60% of maximum heart rate
2. Zone 2: 60% to 70% of maximum heart rate
3. Zone 3: 70% to 80% of maximum heart rate
4. Zone 4: 80% to 90% of maximum heart rate
5. Zone 5: 90% to 100% of maximum heart rate

So, if you are 30 years old, your heart rate zones could be calculated as: Max HR = 220–30 = 190

How do you use these heart rate zones to train?

Each zone gives you a stimulus for your physiological system. The zones calculated above may be used in the following manner to train.

Zone 1: Training in this zone is useful when you want to do a recovery run the day after a hard workout. This zone predominantly utilizes fat as a fuel for burning

Zone 2: Your heart rate in this zone is used for all your “easy pace” and “long” runs. This zone is used for building your endurance base as a runner by accumulating weekly mileage.  

Zone 3: Training in this zone allows you to reach what is called a “steady-state” and your runs maybe 45–90 minutes. Zones 1–3 are aerobic zones, wherein the body burns fat and some carbohydrate in the presence of oxygen. In this zone, you can train yourself to move at an intensity slightly lower than your lactate threshold, which is given in zone 4. Training in this zone will also allow you to get better at your marathon pace.

Zone 4: This zone stimulates the production of blood lactate in your system and this stimulus is essential for training for increasing speed. In this zone, you may be able to speak only a few words between breaths. Recreational runners have their half marathon and 10K paces in this zone. These are called lactate threshold or tempo runs.

Zone 5: In this zone, the body burns the maximum amount of carbohydrates. It is used for executing high-intensity speed workouts using what are called intervals of three to five minutes with recovery in between. This zone is anaerobic and it means that the body burns carbohydrates without oxygen. Beginners are not advised to train in this zone as fatigue buildup and recovery are hard. There is also a likelihood of injury when training in this zone. This zone allows you to train for 5K and 3K races.

Also read: Can You Use Fat As an Energy Source for Running?

Sample training plan for beginners

The first thing to do is to invest in a chest heart rate monitor compatible with a smart watch. Some of these wearables allow you to set an alert for the heart rate zones, so that you know whether you are below or above the training zone.

As a beginner, you should focus on building your endurance by training in zones 1 & 2 for a period of six to eight weeks. The weekly plan should be four days running and two days of strength training. After this phase, you may work towards building up speed for the next four to six weeks using steady-state and tempo runs. Here’s a sample training schedule for you to refer to:

Training phase: Endurance  build-up

Training phase: Speed

Heart rate training is very effective as a tool and method for improving your running performance. The idea is to monitor your heart rate continuously and get used to how it behaves when you run in a certain zone. As you stay consistent with heart rate training, you will adapt to the training and your heart function will get stronger. Consequently, your heart rate will drop for the same pace and this is the moment of realization where you know that you are getting fitter and faster.

Reference
1. Nikolaidis PT, Rosemann T, Knechtle B. Age-Predicted Maximal Heart Rate in Recreational Marathon Runners: A Cross-Sectional Study on Fox’s and Tanaka’s Equations. Front Physiol 2018; 9: 226.