How to Use Heart Rate Training Zones for Triathlon

Athletes are constantly looking for training hacks, turning to the latest and greatest gear to improve their fitness. But the reality is you probably already have the technology for one of the simplest and most useful training tools: heart rate zones. Heart rate is provided in so many training devices now, from the most basic of fitness trackers to—believe it or not—your swim goggles, making heart rate training zones one of the easiest ways to optimize your fitness and performance.

While using heart rate zones may not be the next hot new revolutionary triathlon training strategy, it can still be one of the most effective, giving you greater control over your intensity and effort. If you’re consistently overtraining or, conversely, wondering if you’re working hard enough, training with heart rate zones can help you feel confident in your efforts, no matter the discipline.

The Basics of Heart Rate Zones in Triathlon Training

On a most basic level, the premise of training with heart rate is that when you go harder your heart rate goes up. You can then establish heart rate zones that designate different levels of effort relative to your maximum heart rate and your threshold—ie. what you can hold at a very hard race effort for a sustained period (30-60 minutes).

When training using heart rate zones, one of the most important things to remember is this: not all heart rate zone charts are created equal. Joan Scrivanich, an exercise physiologist and coach at Rise Endurance, explains that some coaches may use a chart with three heart rate zones, while others use five zones—perhaps the most common—or six, all with slightly different variations of heart rate percentages between zones. “If you’re following a workout or plan using zones, make sure you use the corresponding zone chart so that you’re staying within the prescribed efforts,” Scrivanich said. 

No matter the chart, zone one (Z1) will always be the lowest effort, with the top zone considered the highest intensity. These zones also correspond with your rate of perceived exertion (RPE) and with power or pace zones if you’ve established them using a test.

RELATED: Everything Triathletes Need to Know About Training Zones

No matter which heart rate chart or method you follow, the 80/20 training method applies. Simply put, this means 80 percent of your training is done at lower intensities and the other 20 percent accounts for moderate- to high-intensity training. For example, a 2014 study published in the International Journal of Sports Physiology and Performance found that in a three-zone training program—where Z1 is low-intensity, zone two (Z2) is moderate-intensity and zone three (Z3) is high-intensity—triathletes who spent more time training in Z1 had better Ironman performances. This can easily be translated to five heart rate zone too. Barry Stokes, a triathlon and endurance athlete coach based in Kentucky, explains that if you were following a program with five heart rate training zones, 80 percent of your training would take place in Z1 and Z2, with the other 20 percent in Z3, zone four (Z4), or zone five (Z5).

Athletes of all levels can use heart rate zones in their triathlon training. As Scrivanich explains, the zones will always be the same percentage ranges and established the same way from athlete-to-athlete—but the training you do in that heart rate zone is still highly individualized; your heart rate zones are specific to you. 

“Not everyone has the same heart rates and you shouldn’t train with someone else’s zones,” Scrivanich said. “Our genetics, physiology and training are different. So while you can do the same workout as someone else, your heart rates within each zone can vary between you and the other person.” 

When using heart rate zones—especially as a beginner—Stokes adds that it is important to not get too caught up in your numbers relative to those of other athletes. Your maximum heart rate is not indicative of your athletic ability. “Two similar athletes—[same] age, sex and athletic background—may have very different max heart rates and this, in no way, would indicate athlete ‘A’ is a better athlete than ‘B’ and is not a predictor of who may win in a head-to-head race,” Stokes said. 

Why Your Heart Rate Varies Between Disciplines

Besides your personal heart rate zones compared to other athletes, what else will vary is your heart rate across swimming, biking, or running. When using heart rate in triathlon training, you want to have zones that are not only specific to you, but are also specific to each sport. This is due to a number of factors, including body position and weight distribution.  

“Swimming, a horizontal, non-weight bearing activity, will, on average, have the lowest [heart rate] maximum of the three disciplines in triathlon,” Stokes said. “Cycling, as a partial weight bearing activity ([with] five shared points of weight bearing—hands, seat, feet) normally, will have the second lowest heart rate, while running, because it is a full weight bearing activity (two shared points of weight bearing—feet) will have the highest heart rate of the three disciplines.”

What that means is your maximum heart rate for running is likely higher than for cycling, which is higher than for swimming. And then your zones will each be correspondingly adjusted as well—though they will be the same percentage of maximum for the relative sport.

How to Use These Zones in Triathlon Training

Now that you know the basics, you’re ready for a sample chart to see how to put it to use. Again, when sharing this chart, Stokes stresses that 80 percent of training should be done in Z1 and Z2. 

While these percentages will remain the same across each discipline, your heart rate will vary between each. A common way to establish heart rate zones is to simply subtract your age from 220—however this is not individualized and can be highly inaccurate. To establish your specific heart rate training zones, you’ll want to do tests in each of the three disciplines to see where your lactate threshold is. “It’s important to test in each discipline… each of my athletes are given a zone chart with their specific heart rate ranges within each zone for each discipline [based on their tests],” explains Scrivanich.

A 2009 study in the Journal of Strength and Conditioning Research backs this up, noting that—at least for cycling and running—athletes should be doing sport-specific testing to establish training zones.

RELATED: How to Establish Triathlon Training Zones

What does a test to establish heart rate zones look like?

For swimming, a common test is to do a 1,000 yard time trial, and take your pace and heart rate from that effort to establish your threshold and then extrapolate the percentages of each heart rate zone from there. For cycling, a FTP (functional threshold power) test is common. A simple FTP test is to warm-up well, do 5 minutes hard, recover, then do a 20-minute all-out effort to determine your heart rate across that 20 minutes. For running, a similar test to cycling is often used—with a 30-minute all-out effort where you look at your heart rate across the last 20 minutes to establish a threshold. For more benchmark tests to help you establish training zones, check out these. You should also re-test every few months to ensure your zones haven’t changed.

RELATED: Why You Need Benchmark Testing Now More Than Ever

Heart Rate Zones in Triathlon Training Aren’t Perfect

Of course, using heart rate zones are just one piece of the total training puzzle. This is, in part, because your heart rate can not only vary by discipline, but also from day-to-day. According to the American Heart Association, there are a number of factors that influence your heart rate, including stress, caffeine, altitude, sleep, and even the weather (at higher temperatures, your heart pumps more blood). 

“Heart rate isn’t static,” Scrivanich said. “It changes with emotions, weather, quality of sleep, and what we’ve had to eat or drink. This is one of the reasons why it’s important to train with heart rate as well as perceived effort and power.”

That’s why being able to correlate your heart rate with a rate of perceived exertion (RPE) is important, especially if your heart-rate monitor of choice malfunctions and you can’t get a measurement. If you’ve done enough training at set effort levels, then you’ll learn what they feel like. Stokes emphasizes the importance of having what he refers to as an “internalized heart rate and effort clock” to seamlessly equate those heart rate zones into your training and racing by feel. “I don’t want athletes to become so dependent upon monitored heart rate they lose their ‘feel’ for racing,” he said.