Welcome to the Australian Spinal Research Foundation’s Posture Series. Let’s jump in.
First cab off the rank in this series is the important issue of posture and cardiopulmonary function. In recent times, heart rate variability has become somewhat of a rising topic in chiropractic. Whether this improvement in heart rate variability is due to postural correction, removal of subluxations or an improvement in the patient’s state of ease (versus stress) is a matter for further investigation. What we do know, is that it’s but one potential impact of chiropractic care on the cardiopulmonary system. The power of good posture is indeed a potent thing.
In our recent series on stress, we explored how stress impacts posture. Once the amygdala has detected a stressor, one of the primal reactions is to drop the head forward and round the shoulders so we are ready to fight or run. But posture can also be the stressor, as rounded shoulders and forward head posture can tell the brain there is something wrong. Research also shows us there is a clear link between the two.
Among the results of the stress response are elevated heart rate and increased blood pressure – neither of which is ideal if stress becomes chronic and the stress response settles in for the long haul .
But in the smartphone era, we are living in a world that seems bursting at the seams with cases of cervical or thoracic kyphosis. What does this do to cardiopulmonary function apart from impacting the stress response (including heart rate and blood pressure, the latter being an issue there’s a lot of chiropractic research on)?
Rene Caillet MD, author and director of physical medicine and rehabilitation at USC, says “lung capacity can be reduced by as much as 30%” in individuals with a thoracic kyphosis .” This thoracic kyphosis is “very closely linked with several other postural imbalances that play off each-other including: forward head posture, cervical flexion, rounded shoulders, scapular abduction and winging, internal humeral rotation and depressed ribs .” The latter are facts easily gleaned from basic science. Still, research is increasingly linking the thoracic kyphosis with the forward head and rounded shoulders .
In fact, Singla et al found that “Cervical lordosis values were found to be significantly associated with thoracic kyphosis values. Also, there were significant correlations between rounded shoulders and increased thoracic kyphosis .” They went on to link these presentations with:
A growing number of research papers are indicating that cervical kyphosis can have a negative impact on tidal volumes [4,5]. In both Landers et al and Bishay et al, patients exhibited improvements in pulmonary function when they were moved from sitting to supine positions – the latter position effectively relieving the cervical kyphosis. In the case of Landers, it was stroke patients under the proverbial microscope, and these also benefited from thoracic mobilisation . In the case of Bishay, it was a wheelchair bound 22-year old with notable cervical kyphosis and low tidal volume .
But what does lowered tidal volume and lung capacity mean? We don’t really need to view new research asserting that we need oxygen to stay alive, but just how much of a difference oxygenation makes to blood and the various tissues in the body, and then performance and concentration is another topic altogether – one scientists interested in peak human performance still investigate.
On the illness end of the spectrum, lowered lung capacity or tidal volume can play into conditions like asthma, emphysema, chronic obstructive pulmonary disease, pulmonary oedema and bronchitis among many others. On the wellness end of the spectrum, we need good oxygenation to enjoy a broad range of activities, whether athletic, leisurely or even academic. (Who has ever tried to write a brilliant piece of academic work while feeling dizzy or foggy headed?)
Can we claim to cure any of these problems? No. But we can remove subluxations, advise stretches and help patients reclaim up to 30% in lost lung capacity and tidal volumes.
It makes sense that, if we are claiming to make a change to someone’s posture and that this impacts cardiopulmonary function, we should be able to measure it. How do we do that in clinical practice? The main tool chiropractors use may be their hands, but there is a plethora of ways we can measure the impact on cardiopulmonary function without adding to or subtracting from our modality.
As mentioned above, Heart Rate Variability (HRV) is becoming increasingly visible in the world of chiropractic. Heart rate proper may be used as an indicator of health in other ways, but when applied to chiropractic, HRV can give us unique insight into adaptation, as it gives us a clear look at what is happening in the cardiopulmonary system pre and post adjustment. As for how we measure it, CLA (the Chiropractic Leadership Alliance) Insight Station now measures HRV. There are also some wearable wrist devices that can achieve the same thing.
In a recent members video, Dr Michael Hall discussed a cardiac recovery test we can use in practice to assess how fast a patients heart rate comes back down to normal after physical activity. It involved taking their heart rate, getting them to march on the spot for two minutes and then timing to see how fast their heart rate came back down. For adults, a normal resting heart rate should be between 60 and 100 beats per minute, and the lower it is, the healthier a person is thought to be . Dr Hall cautioned that anything over 80 should make us raise an eyebrow.
By using the simple assessment of resting heart rate followed by a simple, non-invasive cardiac recovery test, we can get some insight into a patient’s level of stress and cardiopulmonary function.
Pulse Oximetry is another simple way of measuring cardiopulmonary function. In a 2012 edition of the Journal of Chiropractic Medicine, Hall and Jensen put forward a rationale for its use in chiropractic care, suggesting that it has the potential to be an integral part of chiropractic practice :
Pulse oximetry simply gives us an indication of a patients oxygen saturation levels. It is seen commonly in hospitals, and is as simple as placing a clip on a patients finger in order to glean potentially lifesaving information. Hall and Jensen offered three reasons for the inclusion of pulse oximetry into chiropractic practice:
“1. Pulse oximetry allows for quick and reliable retrieval of oxygen saturation and heart rate values previously not readily obtained or used.
Dr David Fletcher, of CLA, has advised that pulse oximetry is something on the horizon for new editions of the Insight Station, so this technology will soon become easier for chiropractors to get their hands on.
This technology is a simple way to measure tidal volumes. It simply measures how much air you can inhale and exhale quickly, giving insight into the movement of the lungs. Spirometers vary in price from a few hundred to a few thousand dollars. It’s fast, easy, and gives a tangible way to demonstrate an added benefit of chiropractic care.
Spirometers are cheap but if you’d rather avoid the use of another device, measuring chest expansion is an option. (As an added benefit, it costs you even less and can work as a great outcome measure).
We can see from basic science that posture has a significant impact on cardiopulmonary function. We also know that chiropractors are uniquely positioned to assist patients with postural concerns. What the data should show us, now more than ever as instances of cervical/thoracic kyphosis are on the rise, is just how important this could be.
 Stress Series part 3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756015/
 Whitehead M (2015), “How Posture Affects Lung Capacity,” http://www.oregonexercisetherapy.com/blog/how-posture-affects-lung-capacity retrieved 24 Sept 2018
 Singla D, Islamia JM, Nagar J (2017), “Association between forward head, rounded shoulders, and increased thoracic kyphosis: a review of the literature,” Journal of Chiropractic Medicine, (Sep); 16 (30): pp. 22-229 http://www.chiro.org/LINKS/ABSTRACTS/Association_Between_Forward_Head.shtml
 Landers, M, Barker, G, Wallentine, S, Wesley-McWhorter, J and Peel, C (2003),“A Comparison of Tidal Volume, Breathing Frequency, and Minute Ventilation Between Two Sitting Postures in Healthy Adults,”Physiotherapy Theory and Practice, DOI: 10.1080/09593980390194119
 Bishay L, Berde C and Rosen D (2016), “A Cervical Case? Improvement in Pulmonary Function Flows from Sitting to Supine,” https://www.atsjournals.org/doi/abs/10.1164/ajrccm-conference.2016.193.1_MeetingAbstracts.A5611 retrieved 24 Sep 2018
 GONCALVES, Márcia Aparecida et al. Thoracic kyphosis comparison between a patient with chronic obstructive pulmonary disease and a healthy individual by flexicurve method. Fisioter. Pesqui. [online]. 2015, vol.22, n.3 [cited 2018-09-23], pp.333-339. http://dx.doi.org/10.590/1809-2950/14468822032015
 Staff Writer, (2018), “Improvements in HRV under chiropractic care,” Australian Spinal Research Foundation, https://old.spinalresearch.com.au/improvements-in-hrv-under-chiropractic-care/
 Staff writer, (2018), “Resting Heart Rate,” Health Direct https://www.healthdirect.gov.au/resting-heart-rate retrieved 26 September 2018
Hall M, Jensen A (2012), “The role of pulse oximetry in chiropractic practice: a rationale for its use,” Journal Chiropractic Medicine, 11(2), pp. 127-133 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3368980/
Staff Writer (2018), “Spirometry,” Lung Foundation Australia, https://lungfoundation.com.au/health-professionals/clinical-resources/copd/spirometry/