Why Is Heart Rate Variability Important to Willpower?

This article is an excerpt from the Shortform book guide to "The Willpower Instinct" by Kelly McGonigal. Shortform has the world's best summaries and analyses of books you should be reading.

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What is heart rate variability? Why is heart rate variability important to willpower?

Heart rate variability is the variance in time between each heartbeat. The higher the variability, the more relaxed and adaptable your body is to stress. This is related to willpower because people with higher heart rate variability are better at delaying gratification, dealing with stress, ignoring distractions, and exercising self-control.

Continue reading for more information on heart rate variability and what you can do to increase it.

Heart Rate Variability

So if we all have this pause-and-plan response, why doesn’t it kick in more often? Why don’t we utilize pause-and-plan to increase our willpower and make better decisions all the time? Because turning it on isn’t as simple as flicking a switch. There’s another big factor involved, and it’s heart rate variability or HRV—the variance in time between each heartbeat. But why is heart rate variability important?

To understand heart rate variability, you need to know that even when you’re sitting still, your heart rate isn’t completely steady. When a doctor tells you your heart rate is 60 beats per minute, she doesn’t necessarily mean it’s beating once every second. She’s giving you an average. In actuality, there may be 0.9 seconds between two beats, then 1.1 seconds between the next two beats. Greater variability is highly desirable—the higher the variability, the more relaxed and adaptable your body is to stress. That means your brain isn’t in a panicky rush, and it can activate your pause-and-plan response instead of defaulting to fight-or-flight.

How Heart Rate Variability Works 

Two branches of the nervous system control heart rate variability—the sympathetic and parasympathetic systems. When you’re under stress—as in “Oh no, the house is on fire”—your heart rate goes up and stays up. That’s the sympathetic nervous system taking over, and its weapon of choice is the fight-or-flight mechanism (very helpful in a house fire).  

The parasympathetic nervous system, on the other hand, controls your body’s relaxation response. It handles tortoise-speed jobs like digestion, growing your hair, or slowing down your heart. 

Your heart is constantly receiving mixed messages—it’s being told to beat slower by your parasympathetic system and beat faster by your sympathetic system—which causes the fluctuation of heart rate variability. When you have high heart rate variability, it means that your body is responsive to both sets of inputs. It’s an indicator that your nervous system is balanced and your brain is much more likely to invoke the pause-and-plan response. 

However, your nervous system’s balance is easily disrupted by stress, poor sleep, an unhealthy diet, lack of exercise, and other lifestyle factors. When that happens, the variation between heartbeats is low, and your brain and body are on constant lookout for threats. Your fight-or-flight response wins out over pause-and-plan even if there are no true external threats. 

Heart Rate Variability’s Effect on Willpower   

Given all this, it’s no surprise that heart rate variability is considered the best physiological index of willpower. The prime state for accessing willpower is when your heart rate slows but its variability goes up. This makes you feel steady and focused, and your pause-and-plan response takes charge. People with higher heart rate variability are better at delaying gratification, dealing with stress, ignoring distractions, and exercising self-control. 

The research: Heart rate variability can be used to predict who will or won’t be able to resist temptation. For example, when researchers placed a cocktail in front of a recovering alcoholic, they could predict with high accuracy the subject’s ability to resist drinking it based on his or her heart rate variability. (High HRV = strong resistance to temptation.) 

How to Increase Your Heart Rate Variability

Heart rate variability can change according to environmental factors. The food you eat, the air you breathe, and the stress you deal with on a daily basis all affect your heart rate variability. Chronic pain and illnesses negatively impact HRV. Poor sleep and lack of exercise don’t help, either. 

Some of these conditions may not be in your control. If you live in a smoggy city, you may not be able to pack up and move. But there are proactive steps you can take to increase your HRV. Practicing the five-minute meditation you learned in the last chapter is one way. Sleeping more, eating less junk food, and generally taking better care of yourself can also help. If you’d like to track your own heart rate variability, you can invest in a high-tech heart rate variability monitor.  

Why Is Heart Rate Variability Important to Willpower?

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Hannah Aster

Hannah graduated summa cum laude with a degree in English and double minors in Professional Writing and Creative Writing. She grew up reading books like Harry Potter and His Dark Materials and has always carried a passion for fiction. However, Hannah transitioned to non-fiction writing when she started her travel website in 2018 and now enjoys sharing travel guides and trying to inspire others to see the world.

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