Doing bouts of moderately intensive exercise or physical activity for at least a total of 30 minutes every day boosts physical, mental and emotional health. But for some people who suffer from asthma or chronic obstructive pulmonary disease (COPD), exercising for even a few minutes may bring on severe shortness of breath, putting them off from exercising altogether. Those with acute exacerbation of COPD may find it so hard to breathe even without doing any physical activity that they require hospitalisation. However, an easy-to-learn therapy called Acu-TENS that stimulates acupuncture points using electrodes on the skin could potentially help them to ease their difficulty in breathing.

People with asthma temporarily experience difficulty in breathing when a substance or physical exertion irritates and inflames their airways, while people with COPD have a permanently reduced lung capacity owing to disease or surgery. With careful management of their condition, having asthma or COPD has not stopped sufferers from excelling in explosive sports or endurance events. However, for some sufferers, the feeling of struggling to breathe during and after even a little physical exertion is just too off-putting to exercise at all, while a few others find themselves labouring to breathe just going about their daily lives.

Previous studies have indicated that acupuncture on certain acupuncture points (or acupoints) on the body seemed to be able to improve lung function as measured by the amount of air that asthmatic and COPD subjects could forcefully exhale in 1 second after taking a deep breath (known as “forced expiratory volume in the 1st second,” or FEV₁). In research studies conducted in recent years on consenting Chinese asthmatic and COPD patients in Hong Kong and mainland China, Dr Shirley Ngai, Assistant Professor at PolyU’s Department of Rehabilitation Sciences, and her inter-institutional collaborators investigated whether stimulation at acupoints using transcutaneous electrical nerve stimulation (Acu-TENS) could help people with asthma or COPD breathe easier. Acu-TENS, unlike acupuncture, is non-invasive, eliminating the risk of bleeding, infection and other complications, and could potentially be administered as a supplementary aid by the patient himself or herself or a carer after undergoing a short period of training.

In a pioneering 2009 study, Dr Ngai and her collaborators examined the effects of Acu-TENS on FEV₁ and other variables in asthmatic adults after exercise. The 30 subjects were randomly assigned to either a group that would receive Acu-TENS for 45 mins before undergoing a treadmill exercise test, or to a group that would receive Acu-TENS for 45 mins before the treadmill test and Acu-TENS during the test, or to a group that would receive placebo Acu-TENS for 45 mins before undergoing the treadmill test. In the placebo-TENS group, the display screen showed activation as if Acu-TENS were being administered, but unbeknownst to the subjects, the TENS device’s internal circuit had been disconnected. Each subject had an electrode placed over his or her 2 Dingchuan acupoints (定喘穴) on the lower back of his or her neck, and over each Lieque acupoint (列缺穴) on his or her wrists. All subjects in the study could stop doing the treadmill test anytime they felt they could not continue.

The study found that FEV₁ decreased significantly less after the treadmill test in both the Acu-TENS groups than in the placebo-TENS group. The difference in FEV₁ between the 2 Acu-TENS groups and the placebo group was significant, and became even more so at 20, 40, and 60 mins immediately after the test. The effect appeared to be more significant in the group that received Acu-TENS before and during the treadmill test than in the group that received Acu-TENS only before the test and in the placebo-TENS group.

In a 2010 study, Dr Ngai and the same collaborators examined the effect of a 4-week programme of Acu-TENS on COPD patients comprising 5 sessions a week with each session lasting 45 mins. The 28 subjects were randomly assigned to either a group that would receive Acu-TENS over the Dingchuan acupoints; or to a group that would receive placebo-TENS over the Dingchuan acupoints; or to a sham Acu-TENS group that would receive Acu-TENS over the kneecap, which is not an acupoint. Various variables were measured in the subjects immediately before and immediately after each session.

The researchers found that FEV₁, the level of potentially pain-relieving beta-endorphin (β-endorphin) in blood, and the maximum distance walked during a 6-min walking test along a hallway increased in subjects who had undergone Acu-TENS, while their blood oxygen desaturation levels decreased significantly. In addition, the Acu-TENS subjects’ scores in a questionnaire that measured their quality of life in terms of symptoms and activities also improved. In contrast, no significant changes were found in the variables in the placebo-TENS group and those who underwent sham Acu-TENS, which suggested that the effects of Acu-TENS were a result of stimulation at the acupoints rather than from merely electrical stimulation.

Noting that a previous study indicated that Acu-TENS seemed to reduce COPD patients’ symptoms of laboured breathing (dyspnoea), Dr Ngai and another team of collaborators examined whether there was a relationship between FEV₁ increase and dyspnoea reduction in COPD patients resulting from Acu-TENS, and their level of blood β-endorphin and possible inflammatory markers. Their resultant 2011 study is notable for being the first to investigate the immediate effect of Acu-TENS on the level of blood β-endorphin in COPD patients. Forty-four subjects were randomly assigned to either Acu-TENS or placebo-TENS on the 2 Dingchuan acupoints for 45 mins, and a range of variables were measured immediately before and immediately after the single 45-min session.

The research team found that the Acu-TENS subjects had a significant increase in the level of β-endorphin and FEV₁. In addition, they showed a greater decrease in respiratory rate (number of ‘breaths’ taken per minute) and dyspnoea score than their placebo group counterparts. The level of β-endorphin in the placebo group fell. The researchers also found a correlation between the reduction in respiratory rate and the increase in β-endorphin, suggesting that the decline in dyspnoea score may be associated with the β-endorphin increase.

Having studied patients with stable COPD, Dr Ngai and her collaborators from the aforementioned 2009 and 2010 studies decided to examine whether Acu-TENS could help ease the symptoms of dyspnoea in patients with acute exacerbation of COPD. People with acute exacerbation of COPD have a heightened inflammatory response in their airways, often resulting in increased dyspnoea and hospitalisation. In a pioneering study in 2013 of the effect of Acu-TENS on a COPD patient during an episode of acute exacerbation, Dr Ngai and her collaborators conducted a case study of a 74-year-old COPD patient who had been recently admitted to hospital because of an acute exacerbation. The patient underwent a single 45-min session of Acu-TENS with various variables measured immediately before, immediately after, and 45 mins after the end of the session. The research team found that the patient’s high heart rate, respiratory rate, and dyspnoeic sensation declined, suggesting that the patient’s laboured breathing was alleviated somewhat because of the Acu-TENS session.