The breath technique that tames your stress response

Have you heard the phrase “nervous system reset” and wondered what it means exactly? If you aren’t sure what the vagus nerve is, how chronic stress impacts your health, or how to get out of the stress state, the good news is that the biology underneath the idea easy to understand. The better news is that once you understand what’s happening in your body, the tools for addressing it start to make more sense and become easier to implement. This week we’re diving into why a nervous system may stay stuck in stress and three ways to get out of it.

Your autonomic nervous system runs in the background of everything you do; it’s your heart rate, digestion, breathing, immune response. It has two primary branches that balance each other: the sympathetic system, which mobilizes you for action (the classic "fight or flight"), and the parasympathetic system, which returns you to rest, repair, and recovery.

Under acute stress (a near-miss on the highway, a sudden argument with someone close to you, or a loud, unexpected noise, for example) your sympathetic system fires, flooding your body with adrenaline and cortisol. Your heart rate climbs, your pupils dilate, and your blood diverts from your digestive tract to your muscles. This is your body doing exactly what it was designed to do. The problem is that modern life rarely sends the all-clear signal to let our bodies recover.

Instead, chronic low-grade stress (the inbox, the deadlines, the demands of caregiving, or cluttered living) keeps the sympathetic branch partially activated long after the original threat has passed. So the parasympathetic system never has a chance to fully take over, and the "reset" never happens. Over time, this dysregulation compounds.

A "nervous system reset" in physiological terms means deliberately activating the parasympathetic branch. There are a few mechanisms that researchers have studied closely, and the findings are fairly concrete on them.

In 2023, researchers at Stanford published a randomized controlled trial in Cell Reports Medicine comparing different breathwork techniques against mindfulness meditation. The winner was cyclic sighing—a double inhale through the nose followed by a long, extended exhale through the mouth.

How does this work? The extended exhale activates the parasympathetic nervous system, which slows your heart rate. The second inhale fully inflates your lungs and helps clear excess carbon dioxide, strengthening the effect. Your body already does this automatically, but doing it deliberately gives you conscious control over your stress response.

Here's a strange but well-documented trick: splashing cold water on your face or pressing a cold pack to your forehead can actually slow your heart rate and dial down your stress response. It works because cold water hitting the skin around your nose, eyes, and forehead triggers something called the mammalian diving reflex, which directly activates the vagus nerve. A 2022 study in Scientific Reports tested this against acute stress and confirmed it works—vagal stimulation via cold facial contact measurably reduced both heart rate and stress reactivity.

HRV (the variation in time between your heartbeats) is the best noninvasive ways to measure how well your autonomic nervous system is functioning. High HRV reflects a nervous system that can shift fluidly between activation and recovery. Low HRV is associated with chronic stress, poor sleep, and increased cardiovascular risk.

The good news is that HRV is trainable. The breathwork and vagal stimulation techniques above have both been shown to increase HRV in controlled studies, meaning the "reset" isn't just a feeling. It's measurable.

Wondering how you can use the information above to work your way to a lower stress state? Here are a few options:

1. The physiological sigh

Inhale fully through your nose. Without exhaling, take a second short inhale to top off your lungs. Then exhale slowly and completely through your mouth. Repeat 2–3 times. (This is the single fastest evidence-based technique for acute stress reduction.)

2. Cold water on your face

Splash cold water on your face, focusing on your forehead, eyes, and nose. Or fill a bowl with cold water and briefly submerge your face. (Best used in an acute stress moment, but can also be a daily practice.)

3. Track your HRV for one week

Many wearables (Oura, Whoop, Apple Watch) now track HRV. If you have one, look at your baseline. Notice whether the days after you use these techniques show any movement.

4. Protect the gut-vagus pipeline

The vagus nerve is in constant two-way communication with your gut microbiome. Fiber, fermented foods, and consistent sleep all support the microbial environment that feeds into this network. This isn't a quick reset though. It's the infrastructure that makes the quick resets work better over time.

Thirty seconds of deliberate breathing. Cold water on your face. A meal that feeds your microbiome. None of these are dramatic. And that's exactly the point. Small, repeatable, science-backed actions work because you can do them anywhere, any day.

You don’t need a week-long retreat to reset your system. The HPA axis, the vagus nerve, the gut—all of it is responsive. When you give these systems the right signals, they shift into a healthier you.

The information provided about wellness and health is for general informational and educational purposes only. We are not licensed medical professionals, and the content here should not be considered medical advice. Talk to a doctor before trying any of these suggestions.