What happens in Vagus...

...is something you can hack

Let me introduce you to the puppet master in your mind: your vagus nerve. It plays an important role in our autonomic nervous system, which regulates involuntary functions like breathing, digestion, heart rate and blood pressure.

The autonomic nervous system has two main branches: the sympathetic nervous system (SNS), responsible for regulating our "fight or flight" response to danger/ stress; and the parasympathetic nervous system (PNS), which counteracts our SNS responses by inducing relaxation after periods of stress.

When we feel threatened, our SNS shuts down certain functions and activates others, to prepare the body for immediate physical response: either fighting or running away. Our alertness levels are heightened and some of the key functions in our bodies change to respond more efficiently to the perceived threat, including: 

• Lung airways dilate to increase intake of oxygen

• Heart rate increases so that oxygen can reach our muscles quicker

• Pupils dilate to let more light into our eyes and help us see better

• Digestion slows so that energy is saved for the muscles and systems that will fight or run

• The liver produces more glucose to meet expected energy consumption in fighting or running away 

Pause there: we know that our primal responses to danger do not differentiate between the immediate mortal danger of a ravenous lion who identifies you as lunch or a bullying boss who identifies you as their scratching post.

Both situations are going to trigger the same autonomic responses around fighting or running away. Neither is conducive to making reasoned, thoughtful decisions and both are especially ruinous for the health of people with type 2 diabetes: not only is our liver making more glucose which we can barely handle as it is, but we are also producing more cortisol, which inhibits both the production and action of insulin. It's meant to: the stress response is all about flushing the body with the energy it needs to fight or run.

I have failed more often than I've succeeded in helping myself to stay internally calm in the face of stressed, angry or frustrated colleagues and clients. Equally, anxiety and excitement feel the same way, so sometimes I experience happy anticipation as a stressful and unpleasant period of worry.

Meanwhile, my liver is producing more glucose than I need and my whole body is primed for a fight or escape in which I am not actually engaging. It can feel like I'm a sealed bottle of fizzy liquid that's been shaken and left to contain impossible pressures in a quiet, lethal stifle.

Except I'm not up for that. Truly not. Other people don't get to dictate my mood and physical health trajectory when they're having a bad day. So I'm making friends with my parasympathetic nervous system, because I'd rather live to the greatest extent possible in a state of nervous (no, not that meaning of 'nervous') rest.

To do that, we have to feel safe. One of the ways to feel safe is to know what you have to do physiologically to switch from the over-stimulated SNS state of 'fight or flight' to the more relaxed PNS state of 'rest and digest'. Since the vagus nerve plays a central role in the PNS, stimulating it will help trigger the switch. Among other things, the vagus nerve is responsible for:

• Prompting the pancrease to release insulin, the hormone responsible for unlocking the body's ability to shift glucose from the bloodstream to our cells so we can either convert it into energy or store it as glycogen and fat

• Slowing the rate at which the stomach empties, which in turn reduces glycaemic spikes after eating

• Regulating appetite and helping us to eat less

• Reducing inflammation: chronic inflammation causes (among other horrors) insulin resistance, which is one of the causes of type 2 diabetes. Inflammation is a normal immune response to injury or irritation. Acute inflammation helps healing and then passes. Chronic inflammation will be the subject of a separate post. It is best avoided. The chronic inflammation, not the post.

For people with type 2 diabetes, learning to switch to PNS when we are stressed is a powerful way to regulate blood glucose. You can actually train your vagus nerve. The more you stimulate it, the stronger your parasympathetic response.

So how do you stimulate your vagus nerve?

Like this:

• Resonant or box breathing: breathe through your nostrils, in for 5 seconds, out for 5 seconds, hold a little then repeat. Slow breathing (at around 6 breaths a minute) increases your heart rate variability. The heart rate increases on inhalation and decreases on exhalation. The vagus nerve is stimulated and signals a state of relaxation

• Singing, gargling and humming: even for just 30 seconds a day, vocal cord vibration increases PNS activity and lowers blood pressure

• Cold water: either on your face or (if you have no cardiovascular health concerns) immersion in cold water triggers the mammalian diving reflex. As the name suggests, this is a pre-set series of responses mammals have to immersion in water and the result is that our brain and heart are prioritised for oxygen distribution. The heart rate slows and we improve vagal tone

• Mindful movement: walking, yoga and tai chi stimulate the vagus nerve, relax us and can improve glycaemic control in type 2 diabetics

• Eating slowly and chewing more: chewing is an activity that stimulates the vagus nerve. It also improves digestion. Try chewing each mouthful 20 - 30 times and put down cutlery between mouthfuls. Eating more slowly gives you a better chance of noticing how full you are, reduces glucose spikes and therefore lowers the demand for insulin from a likely already tired pancreas

• Neck and belly massage: these are zones the vagus nerve passes through. Gentle massage in these areas will stimulate it. Note that massaging from your right abdomen over to your left in a circular motion will also help faecal matter pass through your colon

• Prioritise pleasure and connection with people: laughter, loving touch, eye contact and positive emotional connection with family and friends are powerful stimulants of the vagus nerve. In terms of blood sugar control, they are the antidote to the invisible influencer of high blood sugar, which is stress. Say no to people who drain you and yes to people who delight you. Notice who is who and dump the drains

• Take care of your gut: the vagus nerve is our central superhighway between the gut and the brain. The microbiome is a subject for a different post. Here, the point is that gut health, vagal tone and brain health are intimately connected. Keeping your gut microbiome healthy involves ingesting: live foods like kefir, kimchi and kombucha; prebiotic fibres found in foods like onions, garlic, oats and barley; and foods rich in polyphenols like brightly-coloured fruit and vegetables, nuts, spices, whole grains and olive oil

• Ear massage: gentle, circular motion massaging of your earlobes and the area above your ear canal stimulates the vagus nerve. You've seen what ear massages can do for your pet dog, haven't you? Maybe don't try it at home with an angry Pit Bull Terrier... maybe don't keep an angry Pit Bull Terrier at home at all if you're interested in feeling safe... I digress

So, next time your boss gets aggressive with you, start rubbing h̶i̶s̶ your earlobes while nibbling on some raw garlic and then throw a bucket of cold water over him. Tell him it's all about improving his vagal tone.

You may lose your job anyway, but at least you'll be in a parasympathetic state with better glycaemic control.

More practical, life-enhancing top tips from Little Miss TooTypeTwo.

© 2025 Marianne Kafena. All rights reserved.