From wired to calm | Exploring the Vagus nerve and how heat and cold exposure support your nervous system
- Megan Pleva
- Aug 1
- 5 min read
Updated: 5 days ago
Stress is part of being human. It sharpens your focus when needed and helps you respond to life’s challenges. But when stress becomes constant, your body adapts in ways that are less helpful. You may feel overwhelmed, disconnected, or simply worn out. This is your nervous system signalling that something needs to change.
At ISKA, we believe in supporting the nervous system from the inside out, using cold and heat exposure to build resilience, promote emotional regulation, and create space for wellness. Our self-directed sessions are designed to help you return to balance. To feel grounded, even when life is full.
Let’s explore the science behind stress, the role of the vagus nerve, and why switching between hot and cold can have a profound effect on the way you feel - physically, mentally, and emotionally.
The autonomic nervous system: A built-in stress and restoration guide
Your nervous system is a complex network of signals running throughout the body. At the heart of this system is the autonomic nervous system, which regulates things you do not have to think about, like heart rate, digestion, breathing, and temperature regulation. It operates in the background, but its impact is front and centre when it comes to your wellbeing. The autonomic nervous system has two main branches:
The sympathetic nervous system: This is your “fight or flight” mode. It increases heart rate, sharpens your senses, and gets your body ready for action.
The parasympathetic nervous system: This is your “rest and digest” mode. It slows your heart rate, supports digestion, and helps you return to calm.
A well-regulated nervous system can move fluidly between these two states, responding to stress when needed, then returning to a place of wellness. But many of us get stuck in one mode, especially the sympathetic. When this happens, you may feel constantly “on,” unable to switch off or settle.
Heat and cold exposure can help restore this natural rhythm.
Heat and cold as tools for nervous system balance
Alternating between hot and cold conditions, what we offer through contrast exposure at ISKA, is one of the most effective ways to support nervous system regulation.
Heat exposure (through infrared sauna) promotes parasympathetic activity, helping muscles relax, improving blood flow, and signalling to the brain that it is time to unwind.
Cold exposure (through ice baths) first triggers the sympathetic system, but when you stay in the cold with controlled breathing, it activates the parasympathetic system instead. This teaches the body to downshift in a high-stress moment.
Over time, repeated exposure helps the nervous system adapt. The result is a more flexible, responsive internal state, what many refer to as nervous system resilience.
The vagus nerve: Your body’s calming pathway
If your autonomic nervous system is the control panel, the vagus nerve is the key switch. It is the longest cranial nerve in your body, connecting your brain to your heart, lungs, and digestive organs. It plays a central role in:
Lowering heart rate
Supporting deep, diaphragmatic breathing
Regulating digestion and inflammation
Promoting calm and emotional regulation
A healthy vagus nerve is said to have high vagal tone, which means your body can quickly shift from stress to relaxation. When vagal tone is low, you may feel stuck in survival mode, anxious, reactive, or emotionally drained. Stimulating the vagus nerve is one of the reasons we include cold exposure in every ISKA session. It is also why our guidance always comes back to the breath.
How cold exposure engages the vagus nerve
Cold immersion is not just about mental toughness. It is a physiological training tool. When you step into cold water, your heart rate spikes and your breath shortens. This is your body’s natural stress response. But what happens next is where the magic lies. With steady, slow exhales and stillness, you override the stress signal. Your vagus nerve begins to activate, your heart rate slows, and your brain receives the message: You are safe. You can stay. This is the shift from sympathetic to parasympathetic mode.
Here is what cold expsure does, when used purposefully:
1. Improves stress resilience
Each plunge is a controlled stressor. By staying calm in the cold, you teach your body how to manage real-world pressure more effectively. Over time, your baseline anxiety drops and your wellness improves.
2. Reduces systemic inflammation
Cold exposure stimulates the vagus nerve, which in turn releases anti-inflammatory neurotransmitters. If you struggle with fatigue, joint pain, or inflammatory conditions, this can be a helpful complement to other therapies.
3. Supports mental clarity and emotional reset
Many people report a post-ice bath high. This is not just anecdotal, it is backed by neuroscience. Cold exposure boosts norepinephrine, dopamine, and serotonin, helping you feel alert, uplifted, and mentally focused.
Why we combine heat and cold
At ISKA, every one-hour session gives you access to both sauna and ice bath. The benefits multiply when used together:
Start with heat to open blood vessels, warm muscles, and calm the mind.
Follow with cold to trigger the stress response and build resilience.
Repeat to encourage lymphatic circulation, reduce inflammation, and reinforce the body’s natural restoration cycle.
This contrast stimulates the nervous system in both directions, then brings it back to centre. It is a powerful way to move from tension to release.
The role of breath: Your bridge to balance
In both heat and cold, breath is your anchor. Long, slow exhales activate the vagus nerve and bring the body into parasympathetic mode. We recommend:
Inhale gently through the nose
Exhale slowly through the mouth
Focus on softening the jaw and relaxing the shoulders
Try box breathing (in for four, hold for four, out for four, hold for four) if your mind is racing
Breath gives you control, even when the temperature says otherwise.
Why we care about nervous system health
At ISKA, we are not here to offer quick fixes. We believe in giving people the tools to tune into their bodies and take control of their wellbeing. Your nervous system is where emotional regulation, physical improvements, and mental focus intersect. By learning how to support it, through temperature exposure, conscious breath, and simple rituals, you build the foundations of a more balanced life. And it is not just for athletes. Whether you are managing work stress, recovering from burnout, or simply seeking clarity, your nervous system matters. We are here to help you reconnect with it.
Final word
There is nothing new about hot and cold exposure. But when you use them intentionally-backed by science and guided by breath, the results feel different. At ISKA, every session is an invitation. To shift your state. To regulate your system. To build resilience, one breath at a time. Whether you come for the physical benefits or the mental reset, what you leave with is the same: calm, clarity, and connection.
Speak soon,
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