Heart rate variability (HRV) measures the fluctuations in time between heartbeats. While it isn’t a health metric you need to overthink, HRV is an indicator of how well the body can adapt to and recover from stress, with a high HRV indicating better overall health and fitness.
HRV is mainly controlled by the body’s autonomic nervous system, says David Benditt, MD, a professor in the department of medicine at the University of Minnesota in Minneapolis. “The sympathetic [nervous system] makes the heart go faster, and the parasympathetic [nervous system] tends to slow it down. The balance between those two, on a beat-to-beat basis, controls the majority of heart rate variability,” he says.
Think of HRV as “a marker of overall health,” says Heather A. Trivedi, MD, a cardiologist at Montefiore Einstein Advanced Care in Elmsford, New York. Higher HRV is linked to better cardiovascular health and stress resilience, and lifestyle changes ranging from physical activity to quality sleep have the ability to improve it.
Exercise is generally helpful for HRV. Endurance activities, high-intensity workouts, resistance training, and exercises that combine these types of exercise may all help improve HRV.Yoga may offer benefits for HRV as well.
“Fitness through exercise will adjust the heart rate variability over time,” says Dr. Benditt. “Aerobic exercise is perhaps the best known way to do that.”
During exercise, HRV actually decreases, but the ultimate results of this activity favorably impact HRV, says Dr. Trivedi.
Quality nutrition can also increase your HRV.
Omega-3 fatty acids may be particularly beneficial for HRV. Conversely, sugary soft drinks may decrease HRV in the short term.
Overall, Trivedi recommends following a heart-healthy diet to support HRV, which includes eating more fruits and vegetables, more whole grains, less saturated fat, and less processed food.
Hydration may be important for healthy HRV as well. “Dehydration adversely affects HRV, as it’s associated with a higher resting heart rate,” says Siddhartha S. Angadi, PhD, a kinesiologist and assistant professor at the University of Virginia in Charlottesville. Proper hydration is also key to safe exercise recovery and maintaining an active lifestyle, which boosts HRV, too.
There appears to be a positive relationship between sleep quality and HRV, seeing as sleep helps the body regulate and recover from stress, and HRV is an indicator of how well the body responds to stress.
Reduced sleep time and conditions like insomnia and obstructive sleep apnea that negatively impact total sleep time subsequently may reduce HRV, likely due to the increased activation of the sympathetic nervous system and decreased activation of the parasympathetic nervous system. Such sleep issues cause stress in the body that often increases a person’s heart rate and reduces the body’s ability to relax and lower the heart rate. Having both insomnia and obstructive sleep apnea may harm the overall function of the autonomic nervous system, negatively impacting HRV as well.
Benditt says consistent, prolonged sleep is likely to improve HRV. Practice good sleep hygiene, such as adhering to a similar sleep schedule every day, to reap these potential benefits. Most adults should aim for 7 to 9 hours of sleep each night.
Those who are interested in tracking their HRV can use a wearable health tracking device to observe how their sleep on a good night versus a bad night impacts this health metric, says Trivedi.
For people who are overweight or have obesity, weight loss is associated with improved HRV, says Benditt.
More specifically, people who are overweight or have obesity and lose weight via healthy lifestyle modifications may see improvements in their HRV. It’s possible, though, that such effects are more a result of the lifestyle modifications that lead to the weight loss than the weight loss itself.
Meanwhile, Benditt cautions against excessive weight loss and being underweight, as it may have an adverse effect on overall heart health. “Weight loss doesn’t mean getting down to levels of unhealthy weight,” he says. “People who get to very low weights get very slow heart rates, and their heart rate variability may go up, but not necessarily in a healthy way.”
Cold exposure has some potential to impact HRV.
“Exposure to cold temperatures initially stimulates the sympathetic nervous system as the body rapidly constricts blood vessels near the skin to reduce heat loss,” says Angadi. “This moves circulating blood volume toward the core and raises blood pressure, which, in turn, stimulates the pressure receptors in the carotid artery and aorta to activate the parasympathetic nervous system, leading to a decreased heart rate over time and increased HRV.” This process encourages the autonomic nervous system to function as it should, balancing between these sympathetic and parasympathetic responses.
This effect on HRV, however, is likely short-lived, says Benditt. Research suggesting that cryostimulation and cold water immersion may increase HRV shows these changes last for only about 15 minutes after cold exposure.
Voluntary slow breathing, a technique that involves intentionally reducing your breathing rate to around six cycles per minute, may help increase HRV due to its activation of the parasympathetic nervous system. Similarly, resonance breathing, also known as coherent breathing, which involves taking about five to seven slow, deep breaths per minute, may improve HRV when included as part of a daily mindfulness practice.
Breathing in a way that extends the length of exhalations longer than the length of inhalations may have a short-term positive effect on HRV as well.
Mindfulness practices like meditation may benefit HRV, too, when included consistently in your daily wellness routine, although evidence of this benefit is limited.
Meditation’s benefits for HRV is a short-term effect, says Benditt. And while mindful breathing and meditation engage parasympathetic activity in the moment, Trivedi says it’s not entirely clear how much of these practices is required to reap long-term benefits.
Both alcohol and caffeine appear to have complex relationships with HRV.
While excessive alcohol consumption, both acute and chronic, decreases HRV, it’s unclear how low and moderate alcohol consumption compare to not drinking at all.But when it comes to general heart health, if you don’t already consume alcohol, continuing to avoid the habit carries the biggest benefits.
“Caffeine is a little harder to decipher,” says Benditt. “Basic pharmacology suggests that caffeine would reduce heart rate variability.”
Research returns mixed results, though. Caffeine acutely increases the action of the sympathetic nervous system, but it can also elevate activity of the parasympathetic nervous system. And following exercise, some studies suggest caffeine may delay HRV recovery, while others find it doesn’t have a significant impact.
“Habitual caffeine intake doesn’t worsen HRV per se, although very high caffeine intake has been shown to worsen HRV in some studies,” says Angadi.
Trivedi suggests not overdoing it with caffeine may be the key, but more research is needed.
There may be a connection between mental and emotional well-being and HRV as well.
For instance, some evidence suggests that people who have anxiety disorders have lower resting state HRV. Other data establishes a relationship between lower HRV and emotional dysregulation. On the flip side, higher HRV is linked to emotional regulation.
“Stress, depression, anxiety, and different life stressors can negatively or inversely impact HRV, so we would assume that relief of those would improve it,” says Trivedi.
Fortunately, a number of strategies can help with emotional regulation that may, in turn, support healthy HRV. For example, practicing gratitude may help increase HRV as well as help with stress management.Practicing compassion may also help improve HRV in people with severe depression.
Heart rate variability is a general measure of health. It indicates how well the body can adapt to and recover from stress, with a high HRV indicating better overall health and fitness.
Healthy lifestyle choices, such as consistent exercise, a nutrient-dense diet, and quality sleep, all support a healthy HRV.
Minimizing harm to your general health, be it from excessive alcohol consumption or poor stress management, protects your HRV as well.
HRV isn’t a metric you need to overthink; instead, it’s another tool you can choose to use to support the adoption and maintenance of healthy habits.
