What You Should Know About Your Resting Heart Rate

You know your heart rate skyrockets during burpees or when a "we need to talk" text pops up on your phone. If you're serious about fitness, you may even train according to your heart rate.

But how often do you pay attention to your resting heart rate (RHR), which is your heart rate when you're 100 percent chill? Here's what you need to know about this very important number.

Healthy Resting Heart Rate 101

Here's a little refresher: Your resting heart rate is a measurement of how many times your heart beats per minute when you're completely at rest. (Think: When you've first woken up in the morning before getting out of bed.) It's an important number because it's a great indicator of your overall health and fitness, namely your cardiovascular health. And, unlike your score in pretty much any sport, a lower number is better.

Essentially, the lower your resting heart rate, the more efficiently your heart is working, says Scott McLean, Ph.D., a human performance and biomechanics specialist and the former principal research scientist at Fitbit, the fitness wearables company. "You have to pump a certain amount of blood around the body per minute," he notes. "If your heart is larger, stronger, and the arteries are clear and working well, you'll pump more blood to the body during each beat, which means that, per minute, you'll need fewer beats to make that happen," explains McLean.

A normal resting heart rate is anywhere between 60 and 100 beats per minute (bpm) for most people, according to the American Heart Association. However, a lower RHR generally implies better health; well-trained athletes may even have resting heart rates as low as 40 bpm, according to the Mayo Clinic.

The Average Resting Heart Rate in the U.S.

Bad news: Research from Fitbit shows that the average resting heart rate in the United States does not bode well for the country's overall health. The wearables company tapped into its giant user database of more than 108 billion hours of heart-rate data to analyze resting heart rates around the world. Of the 15 different countries the company reviewed, the U.S. and Singapore had the highest resting heart rates, at 65.9 bpm, while Italy had the lowest, at 61.8 bpm.

"If you think about it, the U.S. also seems to be ranked highly for a lot of the variables that negatively affect resting heart rate: overall stress, work-related stress, obesity, poor diet, inactivity, etc.," points out McLean.

The few points between the U.S.'s (65.9) and Italy's (61.8) scores may not seem like a huge difference, but those few beats per minute are significant over a lifetime: "We pulled from so much data that even though the difference seems small, it's actually statistically significant and it can also be clinically significant," says McLean. That means the difference is important for both research and IRL health concerns. "Even a 3 or 4 bpm difference in resting heart rate can have a huge impact over time on someone's general health, well-being, and morbidity," he adds. In fact, your resting heart rate has been linked directly to your risk of death.

Why You Have a High Resting Heart Rate — and How to Lower It

The biggest culprits that increase your resting heart rate? Lack of sleep, tobacco use, being overweight or obese, dehydration, and stress, says McLean.

The easiest way to improve (i.e., lower) your resting heart rate is to literally get your blood pumping. Your heart is a muscle, and if you want to get it in good shape, you have to work it out. Yes, that means doing cardio even if you don't think it's necessary for your specific fitness goals.

You don't have to go all-out, though: You can see significant improvements in your RHR just by increasing your overall activity levels each day — no marathon training necessary, says McLean. However, you may want to give HIIT workouts a try: A study published in the Journal of Human Hypertension found that 55-year-old adults who did just one hour per week of high-intensity aerobic training (about 66 percent of maximum effort) lowered their resting heart rate more efficiently than they did through low-intensity effort (33 percent of max effort).

Fitbit's research yielded other interesting results too. Resting heart rates gradually increased with age up until the 40–49 age group (which had the highest RHR for both sexes), then started to decline again. Because Fitbit's huge selection of RHR data is the first of its kind, this finding is pretty novel. Researchers aren't entirely sure why your RHR goes down after peaking sometime in your 40s, although it may have to do with age-related changes in heart mechanics, says McLean.

The health tech company also noticed that female users had a higher average RHR overall than male users by 3 bpm. Before you panic, listen up: This doesn't have any health indications, but rather is a result of anatomical differences in heart size and hormone levels.

How to Measure Your Resting Heart Rate

The best way to get your RHR is to wear a heart-rate monitor (such as a Fitbit or other activity tracker) while you sleep.

No device? To measure it yourself:

1. First thing in the morning (without an alarm clock or other stimulation or distractions), find your pulse on your wrist.
2. Count the number of beats in 30 seconds.
3. Multiply that number by two.

Consider making note of your RHR on two or three different mornings and averaging your results, Cary Raffle, a NASM-certified personal trainer and exercise science pro in NYC, previously told Shape. This can ensure you didn't just record a number on a particularly stressful day or after a rough night's sleep.

Also, be sure to keep an eye on your RHR over time to be aware of what's normal and abnormal for you, said Harley Pasternak, a fitness expert and celebrity personal trainer, in a press release about the Fitbit study. That way, you can monitor how your health is changing and know if you're ever in a situation where you need to seek advice from your doc.