Welcome to part 2 of a 4 part blog on the vagus nerve/HRV
First, a reminder that Heart Rate Variability (HRV) is probably our best ‘guestimate’ of ‘vagal tone’ or the health of your vagus nerve (and wider Autonomic Nervous System) – see part one for more details.
Today we are interested in how to improve the health of your vagus nerve; our focus is on techniques that have at least some scientific support (even if it is in its infancy).
Let’s start with the bleedin’ obvious. Exercise is good for your HRV and drinking truckloads, smoking and taking drugs is very bad. Stress is also bad.
Singing has been linked to heart rate variability (Vickhoff et al., 2013). You don’t even need to be good at it. More mantra type, repetitive or rhythmic singing works better. It might be all about the breath, which brings us nicely to a pet topic of mine – paced breathing.
How often have you been told to “just take a deep breath”.
Before you rush off and do so, it really may not be that simple.
Perhaps what you should be taking is a nice, slow gentle, paced breath. Breathing in for around 5 seconds and out for around 5 seconds. The very best approach would be to find your personal ‘resonant breath’. It is likely to be somewhere around this 4-6 breath per minute. It depends on a number of things, a key one being the size of your lungs, which clearly is difficult to measure.
Without knowing your resonant frequency (and who does right?), I would go for 5.5 seconds in and 5.5 seconds out, without holding on the in or out. Why? A neat study by Lin, Tai, and Fan (2014) compared a range of different breathing patterns and how they influenced HRV. The winner? 5.5 seconds in and 5.5 seconds out, no holding. I have also been ‘playing’ with 3 seconds in and 6 seconds out (from some other information I fell across, I think it is working).
In order to support your paced breathing, there are some great free products on the market. Simply search for “paced breathing” or “breath pacer” in your app store. A favourite of mine is called “paced breathing”. It is super easy to use and allows you to enter half seconds (which some don’t). It also has a sound option so you can close your eyes. Nice.
There is increasing interest over recent decades by scientists in mindfulness meditation. Who isn’t mindfulness getting fashionable with – right?
I used mindfulness meditation to improve HRV in my own Ph.D. based on some research on the topic. Unfortunately, as I dove deeper, I discovered flaws in some of the research. Then in my own research mindfulness meditation did not appear to improve HRV (cue much self pity). I suspect that the amount you need to do to make a difference is difficult to get people to do in our over jammed lives. However, I am leaving meditation in as even 5-10 minutes 3-5 times a week created all sorts of self-reported benefits (around stress, energy, mood etc) to my participants.
Now here is something pretty cool.
The idea is – you can use direct feedback on your HRV to improve it. There does seem to be some research to support this e.g Auditya Purwandini, Muhammad Nubli Abdul, and Nora Mat (2010). You can ‘try this at home’ via a range of cool interactive tools from the Heart Math Institute. I have enjoyed these products but am not prepared to state how accurate they are. I suspect there is a benefit in them and they have published research. However, I am always cautious where research is funded and undertaken by an organization selling the products. As you should be eh?
In an interesting (albeit small) Japanese study, assigned 12 students to either a ‘forest bath’ (not in a tub, just being one with the forest like), or to watch an urban streetscape for 3 days. The forest bathers ended up with better HRV as well as other physiological measures (Han et al., 2016).
Yoga has been linked to improved HRV (Sarang & Telles, 2006; Satyapriya, Nagendra, Nagarathna, & Padmalatha, 2009).
A quick look shows me there is not a huge amount of research on Diet and HRV. I did discover fish (specifically tuna) is linked to HRV (Mozaffarian, Stein, Prineas, & Siscovick, 2008). I suspect diet is likely to fit into the bleedin’ obvious stuff. Poor HRV is a risk factor in heart disease and we are all aware of the general heart disease goodies and baddies (even if some of them have changed over the years – eggs anyone?).
So there we have it, some great places to start working with your vagus nerve/HRV.
There has been a lot of interest in certain unusual techniques e.g. blowing, gagging, bearing down (like you are a going to poop). These will be covered in part 3 of this series. In Part 4 you will learn how to measure your own vagal tone at home.
Dr Rach x
References, Links etc
Here are all the parts in this series:
- Part One: The Wanderer – A Brief Introduction to the
Vagus Nerve (our Hero).
- Part Two: How to improve the health of your Vagus
Nerve – based on scientific evidence.
- Part Three: Vagus nerve stimulation; can you really
‘gag’ your way to good health?
- Part Four: Monitoring your own vagus nerve health using
the variability in your heart rate.
Auditya Purwandini, S., Muhammad Nubli Abdul, W., & Nora Mat, Z. (2010). Heart Rate Variability (HRV) biofeedback: A new training approach for operator’s performance enhancement. Journal of Industrial Engineering and Management, 3(1), 176.
Han, J.-W., Choi, H., Jeon, Y.-H., Yoon, C.-H., Woo, J.-M., & Kim, W. (2016). The Effects of Forest Therapy on Coping with Chronic Widespread Pain: Physiological and Psychological Differences between Participants in a Forest Therapy Program and a Control Group. International journal of environmental research and public health, 13(3), 255.
Krygier, J. R., Heathers, J. A., Shahrestani, S., Abbott, M., Gross, J. J., & Kemp, A. H. (2013). Mindfulness meditation, well-being, and heart rate variability: a preliminary investigation into the impact of intensive Vipassana meditation. International Journal of Psychophysiology, 89(3), 305-313.
Lin, I., Tai, L., & Fan, S. (2014). Breathing at a rate of 5.5 breaths per minute with equal inhalation-to-exhalation ratio increases heart rate variability. International Journal of Psychophysiology, 91(3), 206-211.
Mozaffarian, D., Stein, P. K., Prineas, R. J., & Siscovick, D. S. (2008). Dietary fish and ω-3 fatty acid consumption and heart rate variability in US adults. Circulation, 117(9), 1130-1137.
Sarang, P., & Telles, S. (2006). Effects of Two Yoga Based Relaxation Techniques on Heart Rate Variability (HRV). International Journal of Stress Management, 13(4), 460-475. doi: 10.1037/1072-5245.13.4.460
Satyapriya, M., Nagendra, H. R., Nagarathna, R., & Padmalatha, V. (2009). Effect of integrated yoga on stress and heart rate variability in pregnant women. International Journal of Gynecology & Obstetrics, 104(3), 218-222.
Vickhoff, B., Malmgren, H., Aström, R., Nyberg, G., Ekström, S.-R., Engwall, M., Jörnsten, R. (2013). Music structure determines heart rate variability of singers. Frontiers in psychology, 4, 334. doi: 10.3389/fpsyg.2013.00334