How to Interpret Your Heart Rate Data
There’s a lot of hype around monitoring your heart rate whether you’re an athlete, a recreational gym-goer, or simply tracking your health.
So, you put on your smartwatch and in the next few minutes, it starts reading your heart beat. By the end of the day, you have hours of heart rate data from your resting heart rate to the hour you hit the gym.
Now what?
It’s important to not only have the resources to monitor your heart rate, but to know how to interpret your heart rate data.
How to Interpret Heart Rate Data
To understand your heart rate, you need to understand how your heart works. While we won’t dive into the nitty gritty of biology, let’s first talk about what your heart rate is.
Your heart rate is how many times your heart beats per minute. When your heart beats, it pumps blood through your body, carrying essential oxygen and nutrients with it. When you exercise, your heart beats faster because it’s working harder to get blood and oxygen to your body.
However, when you’re not exercising or “at rest”, your heart beats per minute is referred to as your resting heart rate.
What is a Good Resting Heart Rate?
According to the American Heart Association, a “normal” heart rate for adults is between 60-100 beats per minute (1). However, your heart rate can be affected by plenty of different factors, such as stress, hormones, medication, and activity level.
Like all the other muscles in your body, you want your heart to work as efficiently as possible. So, if your resting heart rate is lower, it typically means it’s healthy. Research suggests (2) that a higher resting heart rate is often associated with obesity, high blood pressure, and lower morality.
Although lower might be better when it comes to your resting heart rate, you don’t want it to be too low. Competitive athletes may have a resting heart rate closer to 40 beats per minute, but for the average person, that can be dangerous.
If your resting heart rate consistently falls under 60 bpm, it can be an indication of bradycardia. This condition can be dangerous because it can limit the amount of blood flow needed to keep your body functioning properly.
On the other hand, if your heart rate consistently rests above 100 bpm, it can be an indication of tachycardia. This condition can be dangerous because your heart may not have enough time to fill with blood between beats, which can hinder the amount of blood and oxygen your cells need.
Monitoring your resting heart rate can be an important way to keep track of your overall health, but you can track your heart rate for much more.
Your Heart Rate and Exercise
When you exercise, your heart works harder. You probably already knew this, but do you know how much harder your heart works?
Knowing your target heart rate when you’re exercising can help contribute to better overall health, but also to better performance, weight loss, and other fitness goals. There are several gyms that have built their brand off of heart rate monitoring during a workout, and you can track your heart rate on your own too.
Understanding Your Maximum Heart Rate
In order to understand your heart rate when you’re exercising, you need to know what your maximum heart rate (HRmax) is. Your max heart rate is what it sounds like – the amount of times your heart can beat within a minute while under stress.
Many factors can affect your HRmax, such as activity level, age, size, and genetics.
There’s a simple formula you can use to help determine your estimated maximum heart rate, which is 220 minus your age. So, if you’re 40 years old, your HRmax would be around 180. It’s important to note that this is just a ballpark number and to get your true max heart rate, visit your doctor.
Your Target Max Heart Rate
So, you’ve strapped on your smartwatch, and you’ve calculated your HRmax, but what should you be shooting for during your workout?
You shouldn’t be trying to reach your maximum heart rate the entire workout because it can be dangerous, and it’d be nearly impossible to sustain that level of intensity unless you’re a trained athlete. Instead, Harvard Health Publishing of Harvard Medical School suggests trying to shoot for these goals (3):
64% to 76% of your HRmax for moderate intensity exercise
77% to 93% of your HRmax for vigorous-intensity exercise
Target Heart Rate for Weight Loss
While you may be using your heart rate data to determine the intensity of your workouts, you may also have other health and fitness goals in mind. If your goals include losing weight, studies suggest there is an optimal heart rate zone to train in for maximal fat oxidation – or the breakdown of fats (4).
What some refer to as the “fat-burning” zone was examined in this study and was found to be between 67 - 87% of your max heart rate. This zone was also found to be beneficial for aerobic fitness.
Target Heart Rate for Improved Endurance
If your sport requires more endurance, such as marathon runners, you need to train in a specific way in order to help improve your performance. Although both runners, a sprinter and a marathon runner need to train differently to optimize their movement.
Studies suggest that athletes trying to increase their endurance should train about 80% of the time in the zone 2 heart rate, which is about 60-70% of your HRmax (5). However, 20% of their training should be dedicated to zone 3 or high intensity training.
Target Heart Rate for Improved Power
Athletes that use short and powerful bursts of energy, such as football players or sprinters, need to train differently than endurance athletes to help increase their power output.
Research shows that training in short intervals of between 10 to 40 seconds at >90% of your HRmax can be beneficial for aerobic capacity (6). However, it’s important to note that this study was performed on trained athletes, and the average person should understand the possible risks of training in this zone and work with an experienced coach if needed.
Sources:
American Heart Association. (2024, August 12) Target Heart Rates Chart. https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates
Jensen MT, Suadicani P, Hein HO, et al Elevated resting heart rate, physical fitness and all-cause mortality: a 16-year follow-up in the Copenhagen Male Study. Heart 2013;99:882-887.
Corliss, Julie. All About Your Heart Rate. Harvard Health Medical School. (2023) https://www.health.harvard.edu/heart-health/all-about-your-heart-rate
Carey, Daniel G. Quantifying differences in the "fat burning" zone and the aerobic zone: implications for training. Journal of Strength and Conditioning Research 2009; 7(2090-5). doi: 10.1519/JSC.0b013e3181bac5c5
Sperlich, Billy, Stoggl, Thomas L. The training intensity distribution among well-trained and elite endurance athletes. Frontiers in Physiology 2015; 6(295). doi: 10.3389/fphys.2015.00295
Bangsbo, Jens, Hostrup, Morten. Performance Adaptations to Intensified Training in Top-Level Football. Sports Medicine 2022: 53(3):577-594. doi: 10.1007/s40279-022-01791-z