You don't need willpower to exercise. You need to exercise to have willpower.

Welcome to Stretch, your guide to experimenting with your mental and physical performance. Weekly, highly practical, and guaranteed to teach you something new about your mind and body!

Here’s what most of us get wrong when we start new projects or build new habits:

Willpower is not just a mental construct.

You can't think and plan and push your way to more willpower (at least not without burning yourself out!)

Willpower is a matter of physiology.

Yes, grit and determination are important. But you also need to get your body on board.

That is one of my biggest takeaways from the book The Willpower Instinct by Stanford psychologist Kelly McGonigal:

Willpower is a temporary state of both mind and body that gives you the awareness and strength needed to override your impulses and stick to your goals.

In the book, McGonigal outlines two distinct nervous system responses:

• The instinctive “fight-or-flight” response

• The measured “pause-and-plan” response

Each response triggers very different reactions in the brain and body, from variations in heart rate, blood pressure, breathing, to muscle contraction and other automatic functions.

Now, when you’re faced with a willpower challenge (say… resisting a bag of peanut M&M’s while grocery shopping 🙄), which nervous system response would serve you best?

That’s right. You want your body to activate the “pause-and-plan” response. It's like a mental pause button, giving you time to think, 'Do I really need these? Will I feel better after eating them, or will I just be hunting for the next sugar rush?'

Research shows that the single best physiological measurement of the pause-and-plan response is something called heart rate variability, or HRV.

The best physiological measurement of the pause-and-plan response: Heart Rate Variability (HRV)

Before we talk about the link between HRV and willpower, let’s define HRV.

HRV refers to the variation in time between each heartbeat. It’s considered a key indicator of autonomic nervous system (ANS) function, particularly the balance between the parasympathetic and sympathetic branches.

Higher HRV is associated with better health, resilience, and adaptability to stress. Generally, the more relaxed and free from stress you are, the more variability in the time between each of your heartbeats.

At first, I struggled with grasping this concept. This analogy helped me understand it better:

Imagine your heart as a drummer in a band. Instead of keeping a constant beat, a good drummer varies the beats just a little – some fast, some slow – to make the music feel more lively.

HRV is like measuring those tiny variations in the beats. If the drummer only played a rigid, unchanging beat, the music would not feel as alive or vibrant.

Now, why is a higher HRV better for us?

Still using our band analogy, if our drummer can vary the beats more (higher HRV), it means he's more adaptable and can respond better to changes in the song or the band's rhythm.

Similarly, a heart with higher HRV means it can adjust to changes quickly, whether those are emotional stresses, physical challenges, or other demands. It's a sign that the body's control system (specifically, the autonomic nervous system) is flexible and in good shape.

On the other hand, if the drummer has a very rigid beat pattern (low HRV), it could mean he's not as adaptable. Similarly, a low HRV can be a sign that our body might not be handling stress or challenges as well as it could.

Make sense?

Are you thinking: “What does all of this have to do with M&M’s or exercise as promised in the subject line?!”

Let’s keep going!

HRV is not a direct measure of willpower but as explained in the book, research shows it can be seen as an indicator of the body’s stress response and adaptability—which are essential components of willpower.

• When your HRV is high, it suggests your body can efficiently manage stress. This state is linked to better self-control or willpower. Essentially, if your body is good at handling stress, you might find it easier to resist temptations or stick to challenging tasks. (That’s that pause-and-plan response.)

• When your HRV is low, it can mean your body's stress response isn't as adaptable. In such cases, you might find it harder to exercise willpower. Stress or tiredness can make it more challenging to make good decisions or stay disciplined.

Okay, so we’ve defined HRV and we’ve established that it’s a good physiological measure of our capacity for self-control.

That begs the next important question: can you improve your HRV and if so, how?

Since this newsletter is all about practical tools to experiment with your mind and body, I wouldn’t be writing about this if you couldn’t! 😉

2 simple, effective and free ways to improve your HRV

Many factors have an influence on your HRV:

• What you eat (plant-based, unprocessed foods over junk food)

• Where you live (air quality)

• Your mental state (levels of stress, anxiety, anger, depression, loneliness)

You might not have control over all of these things, and even if you do, they’re not a quick fix.

But there are two simple things we can all do, starting today.

1. Daily movement

Movement is quite literally a wonder drug. There are the immediate, short-term benefits. Reducing cravings, endorphins, etc etc. We all know this by now.

But the long-term effects of exercise are even more impressive.

Exercise enhances the biology of self-control by increasing baseline heart rate variability and training the brain. Physical exercise makes your brain bigger and faster, and the prefrontal cortex shows the largest training effect.

I like in the book how McGonigal addresses these two common questions:

• What kind of exercise is best?

  The body and brain don’t seem to discriminate, so whatever you are willing to do is the perfect place to start. Gardening, walking, dancing, yoga, team sports, swimming, playing with your kids or pets—even enthusiastic housecleaning and window-shopping qualify as exercise.

  Anything above and beyond the typical sedentary lifestyle will improve your willpower reserve.

• How much exercise do I need to do?

  However much you are willing/able to do. There’s no point in setting goals you won’t be able to keep. A 2010 analysis of ten different studies found that the biggest mood-boosting, stress-busting effects came from five-minute doses of exercise, not hour-long sessions. There’s no shame—and a lot of potential good—in committing to just a five-minute walk around the block.

You don’t need willpower to exercise. You need to exercise to have willpower.

2. Coherent Breathing

Coherent breathing involves taking slow, controlled breaths, typically around 5.5 to 6 breaths per minute.

When you breathe at this slow, steady rate, it strengthens the baroreflex—a physiological phenomenon where heart rate increases during inhalation and decreases during exhalation.

To practice coherent breathing, you can follow these steps:

• Find a comfortable position where you can relax—either sitting or lying down. Begin by noticing your breath without changing anything.

• Slowly breathe in through your nose, expanding your belly, to the count of 5 or 6 seconds. Then, slowly breathe out through your nose to the count of 5 or 6 seconds, releasing your belly.

• Start with a few minutes at a time and gradually increase as you become more comfortable. The goal is to work your way up to practicing this pattern for 10 to 20 minutes a day.

It’s important to breathe naturally and not force the breath. The pace of 5 to 6 breaths per minute is just a guideline, and you can adjust this if it's uncomfortable.

The key is to maintain a slow, steady rhythm that helps you relax and focus.

Here’s Andrew Huberman doing a coherent breathing exercise with creative producer Rick Rubin. You can use an app like Breathe to help you time your inhales and exhales, with a similar gong sound.

🔬 Let’s experiment…

• Track Your HRV: Use a wearable device like an Oura Ring, Apple Watch, or Whoop to monitor your HRV.

• Notice Your Responses: Try to be more aware of your reactions when faced with a willpower challenge. Are you leaning towards a "fight-or-flight" response or a "pause-and-plan" one?

• Experiment with Daily Movement: Remember, any physical activity counts—a brisk walk, a dance session, or just some active housecleaning. Notice how this affects your mood and decision-making.

• Practice Coherent Breathing: Set aside a few minutes each day for coherent breathing exercises. Start with just 2-3 minutes and gradually increase. Pay attention to how this practice impacts your stress levels and your ability to handle willpower challenges.

Thanks for reading!