If you wear a smartwatch or fitness tracker, you probably already have access to a constant stream of data about your heart health.
Beyond basic heart rate monitoring, smartwatches and fitness trackers can also measure and track heart rate zones, heart rate variability, and heart rate trends.
This information can be powerful for your health and fitness, if you are willing to experiment with different intensity levels during exercise and understand the limitations of the data.
To make the data useful, Kathryn Larson, a cardiologist at the Mayo Clinic Sports Cardiology Clinic in Rochester, Minn., asks patients about their health and fitness goals. “The discussion changes a lot depending on what the patient or athlete wants to do with that data,” she said.
For people looking to develop an exercise habit, heart rate data can be a great tool for understanding how their fitness level is changing over time. For more experienced athletes, heart rate zone training can help improve speed and endurance.
How to measure your heart rate
To measure your heart rate without a wearable device, feel for your pulse in your neck or wrist. Count the number of beats you detect in 15 seconds and multiply that number by four.
Your resting heart rate is the number of times your heart beats in a minute when you are not exerting yourself. Your maximum heart rate, which can be roughly estimated based on your age, is a measure of how fast your heart beats during intense exercise.
Most fitness trackers, GPS running watches, and Apple Watches measure heart rate using a small light to measure changes in the blood flowing through the vessels in your wrist throughout the day. Chest strap monitors may be slightly more accurate than watches, but they are generally only worn during exercise.
A healthy resting heart rate is generally between 60 and 100 beats per minute, although there can be many individual variations. Athletes and people in good physical condition often have a lower resting heart rate.
The Basics of Heart Rate Zone Training
Zone training involves structuring your exercise program around five heart rate zones, which range from relaxed effort to your maximum intensity. Training this way can help you design workouts targeted at specific goals, such as building endurance or improving efficiency.
Each zone is based on a percentage of your maximum heart rate: in zone one, for example, you should reach 50 to 60 percent of your maximum heart rate, while zone five requires 90 to 100 percent of your heart rate. maximum. Many fitness trackers can estimate your heart rate zones and tell you which zone you are in during a workout. But you can also replicate a zone workout based on your own sense of effort.
“The best way to really understand the zones is to understand the effort and the goal,” said Dr. Tamanna Singh, a cardiologist and co-director of the Cleveland Clinic Sports Cardiology Center, adding that different levels of exercise intensity trigger different physiological processes. in the body.
Zone one should be easy, comparable to a warm-up or cool-down. You should be able to “sing a song or recite a Shakespearean sonnet without interruption,” Dr. Singh said.
Zone two should be slightly more difficult. You should be able to hold a conversation, but you may need to breathe here and there, Dr. Singh said. Training in zone two is essential for building endurance and expanding your aerobic capacity. During endurance sports like running and cycling, most of your training time should be spent in this zone.
Zone three isn’t as durable as zone two and you might feel the need to take more breaks between conversations, Dr. Singh said. Many runners refer to this level of effort as “tempo.”
Zone four is what runners and cyclists would call threshold training, “something you could probably maintain for maybe 45 minutes or an hour maximum,” Dr. Singh said.
Zone five, your maximum, total effort is an intensity that Dr. Singh considers a “red line.” There is no space for conversation, as your body works to develop its ability to function with less oxygen.
Athletes in sports like swimming, running and cycling typically spend most of their training time in zones one, two and three, building aerobic health and endurance, with limited time in zones four and five based on individual objectives.
Many factors (e.g. stress, weather, and sleep) can impact your heart rate. It is therefore important to consider your own sense of exertion alongside your heart rate measurements. If you want to experiment with a zone-structured workout plan, programs like Orangetheory and Peloton also offer heart rate-based workouts.
Heart rate variability
Many wearable devices also calculate the user’s heart rate variability, or HRV. The measurement tracks how your heart rate naturally fluctuates from beat to beat, and generally speaking, it can be used to monitor how much you’re recovering or feeling tired between workouts.
Numbers higher than your own benchmark generally indicate a healthier, well-recovered cardiovascular system. (Most fitness trackers and smartwatches can estimate your baseline for you, after collecting enough data.) Lower numbers, especially after a hard workout, could suggest your body still needs more time to recover. But, like other heart rate measurements, HRV can also fluctuate based on non-exercise factors, including illness and alcohol consumption.
Many doctors say there is not yet enough data on HRV to use as a basis for health or training decisions. Dr. Seth Martin, a cardiologist at Johns Hopkins Medicine, said he considered the figure “interesting but not as actionable” as other heart rate data points.
The fine print
Although heart rate data can provide useful insights into your health, experts advise against relying too much on this data.
“Any device sometimes detects things accurately and can sometimes be unreliable,” Dr. Larson said, adding that any abnormalities that might cause concern should be a sign to talk to your doctor.
Using a conversation test — trying to have a conversation, even just with yourself, during a workout — can be as helpful as checking your heart rate. And paying attention to your state of recovery or fatigue can be as helpful as monitoring your HRV.
Dr. Larson said some patients can become consumed by the data. In these cases, she urges them to look at the bigger picture: “How much of this data is actually useful, or how much is it distracting from the more important issues at hand?” »