WHAT IS ENDURANCE TRAINING (ET)?
Endurance training, also referred to aerobic exercise increases breathing and heart rate and as a result improves one’s overall fitness[1]. Examples of endurance exercise consists of walking, swimming, running, etc. COPD patients are recommended by medical professionals to undergo ET. This is done to try and improve muscle strength, increase exercise tolerance and reduce the feeling of breathlessness (dyspnea)[2]
INTRODUCTION
Numerous studies have been conducted to try and pinpoint the exact health benefits of endurance training for patients with COPD. Some studies emphasis patients who undergo endurance training will see a significant change in their overall health. Whilst, some argue based on extensive research conducted, that endurance training alone will only demonstrate a slight improvement in health and for maximum health benefit, endurance training should be accompanied with another form of training. Regardless of these conflicting arguments, it is agreed upon that exercise training is a crucial element of pulmonary rehabilitation with patients that suffer from COPD.
WHAT STUDIES HAVE BEEN CONDUCTED?
Patients that suffer from COPD find that their muscle strength decreases[6] which ultimately affects their daily life. Daabis et al[7] conducted a 2016 study to evaluate if endurance training [ET] would benefit patients who suffer from COPD or if combining strength and endurance training would be a better alternative. It consisted of 45 COPD patients randomly allocated to three groups. Group 1 consisted of patients who only completed ET. Group 2 combined endurance and strength training whilst the last group only received medical treatment (control group). Patient’s symptoms, exercise capacity, muscle strength and their health-related quality of life (HRQOL) were all assessed. Patients in group 1, completed 30 mins of treadmill at high intensity and free weights were used. This study found those who completed ET, there was a significant improvement in patient’s HRQOL and in the mMRC dyspnea scale-a 4-point scale used to assess the severity of dyspnea[8]. It also found that there was not a significant increase in muscle strength in patient who suffer with COPD.
In contrast, studies conducted by Bernard et al[9] and Ortega et al[10], both found out that there was actually increased muscle strength in COPD patients who completed ET alone. Inconsistencies between these studies may be due to differences in the intensity of training and also the manner in which the study was conducted. The duration of these studies differed, one was 8 weeks, whilst the other was 12 weeks long. It is plausible, that by increasing the duration of the study, evidence will show muscle strength does increases in ET . The study conducted by Daabis et al, not all patients completed 100% of the scheduled sessions which affected the final result. Regardless of the discrepancies found, ET should not be discredited and should be a mean of helping COPD patients improve their overall health as all three studies report benefit.
Table 4 shows ET improves a patient’s breathless score and improvements were seen in the mMRC dyspnea scale, patient’s emotion and fatigue levels.
It is noted that ET in COPD patients demonstrates benefits and as a result, research has been conducted to see if there would be any additional benefits when intensity of ET when increased. Santos et al[12] conducted a study to evaluate if having 2 different aerobic training intensities will show any changes on HRQOL, symptom control and exercise tolerance in COPD patients. It consisted of 34 patients with severity of COPD ranging from mild to very severe. They took part in an equivalent/non-inferiority trial, randomly allocated and was controlled. The patients were split into two groups, where the 1st group completed aerobic training intensity of 60% maximum work rate (Wmax) and the 2nd group at 80% max. It was found that ET at an intensity of 60% (Wmax) had significant impact on the patient, however there was no additional benefit when the intensity was increased to 80% (Wmax) when HRQOL, patients exercise control and patient’s symptom control were assessed
Similarly, Dourado et al[13], Foglio et al[14], and Normandin et al[15] show that aerobic intensity of at least 60 % (Wmax) had a significant impact on the symptom control which is assessed by dyspnea index. When assessing the effect on HRQOL, this study showed aerobic training had a positive effect, which is also in accordance with studies conducted by Bernard et al[16], Pereira et al[17] and Foglio et al[18] even though a wide range of intensities was used. However, there is evidence to suggest that that there are physiological benefits for COPD patients who undergo higher ET intensities,[19] which is shown by research conducted by casaburi et al[20] and Bernard et al. In essence, Santos et al study and other studies discussed demonstrates that an ET intensity of 60% (Wmax) or even higher had a positive effect on patient’s centred outcomes and there is also physiological benefits. However, the notion of increasing the intensity of ET, contests with advice given by rehabilitation professionals.
CONCLUSION
Based on the literature discussed, endurance training aids patients that suffer from COPD and improves many aspects of their daily life. For instance,[21] ET is proven to help strengthen the heart, lungs and as a result improves the body’s ability to use oxygen. This then aids the decrease of one’s heart rate and blood pressure. These combined will improve breathing, which means when COPD patients exercise, they will not need to work as hard. For the future, it would be beneficial for the duration of the studies to be increased, having more patients complete the studies would see if there is any further benefits of ET that need to be noted. These studies used different forms of endurance training, which means that some studies examined benefits of ET on the upper body, whilst others inspected the lower body. As a result, these studies will see different benefits and results will differ. Lastly, these studies had different exclusion criteria when enlisting volunteers, which ultimately affects the final data collected by the researchers.
Reference:
[1] http://www.heart.org/en/healthy-living/fitness/fitness-basics/endurance-exercise-aerobic
[2]Knaut C, Mesquita CB, Caram LM, et al. Assessment of Aerobic Exercise Adverse Effects during COPD Exacerbation Hospitalization. Can Respir J. 2017;2017:5937908.
[3]https://www.google.com/search?biw=1920&bih=889&tbm=isch&sa=1&ei=BJLtW5qBCcOegAb6lICQDA&q=running&oq=running&gs_l=img.3..0i67k1j0l2j0i67k1j0l3j0i67k1j0l2.99092.101608.0.102081.7.5.0.2.2.0.121.309.4j1.5.0….0…1c.1.64.img..0.7.320….0.5RtI5yHTzYA#imgrc=FZY76ImrDGWqsM:
[4] https://www.google.com/search?q=cycling&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjjoKXQ-dbeAhWq4YUKHVkHD6sQ_AUIDigB&biw=1214&bih=879#imgrc=rSbrEiS0CvJpcM:
[5] https://www.google.com/search?biw=1214&bih=879&tbm=isch&sa=1&ei=fbDtW8jpNf2Aur4P-sGw2AU&q=swimming&oq=swimming&gs_l=img.3..0j0i67k1l2j0l3j0i67k1l2j0j0i67k1.20162.21453.0.22006.8.5.0.3.3.0.103.448.4j1.5.0….0…1c.1.64.img..0.8.463….0.mxHZSnxf0xg#imgrc=wsEvbJ6DqFradM:
[6] https://respiratory-research.biomedcentral.com/articles/10.1186/rr60
[7] https://www.sciencedirect.com/science/article/pii/S0422763816300851
[8] https://www.verywellhealth.com/guidelines-for-the-mmrc-dyspnea-scale-914740
[9] S. Bernard, F. Whittom, P. Leblanc, J. Jobin, R. Belleau, C. Bérubé, G. Carrier, F. Maltais
Aerobic and strength training in patients with chronic obstructive pulmonary disease
Am. J. Respir. Crit. Care Med., 159 (1999), pp. 896-901
[10] F. Ortega, J. Toral, P. Cejudo, R. Villagomez, H. Sanchez, J. Castillo, T. Montemayor
Comparison of effects of strength and endurance training in patients with chronic obstructive pulmonary disease
[11] F. Ortega, J. Toral, P. Cejudo, R. Villagomez, H. Sanchez, J. Castillo, T. Montemayor
Comparison of effects of strength and endurance training in patients with chronic obstructive pulmonary disease
[12] Catarina Santos, Fátima Rodrigues, Joana Santos, Luísa Morais and Cristina Bárbara
Respiratory Care November 2015, 60 (11) 1603-1609; DOI: https://doi.org/10.4187/respcare.03663
[13] V.Z. Dourado, S.E. Tanni, L.C. Antunes, S.A. Paiva, A.O. Campana, A.C. Renno, I. Godoy
Effect of three exercise programs on patients with chronic obstructive pulmonary disease
Braz. J. Med. Biol. Res., 42 (2009), pp. 263-271
[14] Seven-year time course of lung function, symptoms, health-related quality of life, and exercise tolerance in COPD patients undergoing pulmonary rehabilitation programs
Foglio, Katia et al.
Respiratory Medicine, Volume 101 , Issue 9 , 1961 – 197
[15] An Evaluation of Two Approaches to Exercise Conditioning in Pulmonary Rehabilitation
Normandin, Edgar A. et al.
CHEST , Volume 121 , Issue 4 , 1085 – 1091
[16] https://www.atsjournals.org/doi/abs/10.1164/ajrccm.159.3.9807034
[17] https://www.sciencedirect.com/science/article/pii/S2173511510700750
[18] https://www.sciencedirect.com/science/article/pii/S0954611107001497
[19] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.511.9299&rep=rep1&type=pdf
[20] https://www.ncbi.nlm.nih.gov/pubmed/1986689?dopt=Abstract
[21] https://my.clevelandclinic.org/health/articles/9450-copd-exercise–activity-guidelines
