Not Just BMI: This Important Number Is A Great Indicator Of Heart Health

Maintaining a healthy heart is a lifelong endeavor that involves numerous factors. Unlike age, sex, and genes, some of these factors may be in your control, including smoking status, exercise habits, and your diet. The more risk factors you have, the higher your risk for heart disease. As obesity rates dramatically climbed between the 1980s and early 2000s, healthcare professionals also included a high body mass index (BMI) as yet another risk factor for poor heart health. Yet it can also be argued that BMI seems to get all of the attention, when there are also other numbers that can paint a better overall picture of your individual heart health. Focusing solely on BMI also raises the risk of missing important health data, and it doesn't account for one's body composition, the way waist-to-hip ratio does. One often overlooked heart health indicator is your resting heart rate, which can be linked to both modifiable and non-modifiable risk factors that are worth discussing with a doctor.

Resting heart rate refers to the number of times your heart beats each minute. It's measured when you are awake, but also calm and at rest — not during times of stress, nor if you're standing up or exercising. What's considered a "normal" heart rate range is anywhere from 60 to 100 beats per minute (bpm), which can also vary by age, fitness level, and whether you take any medications. However, there are various other factors that can explain why your resting heart rate might be lower than 60 or higher than 100. Some of these include temporary health issues, while others may point to more serious problems with your heart.

A low resting heart rate is considered any number below 60 bpm, although there are some innocuous causes of a lower heart rate. First, many adults who are considered extremely fit may have resting heart rates around 40 bpm because their hearts do not need to work as hard. It's also possible for your resting heart rate to dip slightly below 60 bpm while sleeping. Certain medications can lead to a lower resting heart rate, including beta blockers and other medications prescribed for arrythmia. However, a resting heart rate lower than 60 bpm can also indicate bradycardia. When left untreated, bradycardia can lead to heart failure and possibly cardiac arrest.

On the flipside, a resting heart rate above 100 bpm is called tachycardia. Sometimes a higher-than-normal resting heart rate can be temporary. Possible triggers include high stress, physical exertion, and illness. Certain medications can also contribute, including decongestants, serotonin and norepinephrine reuptake inhibitors, and some antibiotics. Tachycardia may also be associated with more serious health conditions, such as atrial or ventricular fibrillation. Without treatment, tachycardia may lead to heart failure, heart attack, stroke, or cardiac arrest, as well as kidney and liver problems.

Also, while obesity is sometimes associated with tachycardia, this doesn't mean that all adults with higher BMIs automatically have abnormal heart rates. If a doctor advises weight loss to reduce the burden on your heart, such efforts might lead to a normal resting heart rate if yours is out of the normal range. Age can also play a role in heart rate changes — your risk of a heart attack goes up after 65.

The issue of a lower- or higher-than-normal resting heart rate isn't based on one reading alone. Instead, a doctor will likely consider multiple readings as better indicators of overall heart health, and also investigate individual factors impacting the way your body regulates your heart rate. As the American Heart Association notes, a long-term pattern of an increasing heart rate is more indicative of future heart issues. In fact, a resting heart rate that gradually increases over time may be linked with a higher risk of heart failure. While the normal range is anywhere between 60 and 100 bpm, Harvard Health says that most healthy adults experience an average resting heart rate of 55 to 85 bpm.

Aside from your resting heart rate, it's always a good idea to talk with a doctor about other factors that might be impacting your overall heart health. They can recommend possible solutions for modifiable factors that increase your risk for heart disease, such as high blood pressure, high cholesterol, diabetes, and smoking. As one analysis published in The Lancet in 2019 found, most cases of cardiovascular disease and related deaths are attributed to modifiable risk factors. Such results were based on data of more than 155,000 adults from 21 countries.

In addition to modifying risk factors where you can, it's also important to alert a healthcare professional if you suddenly notice any abnormal changes in your pulse or heart rate data on a fitness watch or other wearable monitoring device. This is especially the case if you experience other unusual symptoms, such as dizziness and breathing difficulties.