Exercise as Prevention and Treatment of Heart Disease
The exceptional economic growth and continuous modernisation of Asia, Hong Kong included, has brought about increasing risk factors and incidence of coronary heart disease (CHD). (1) In 2015, heart diseases accounted for the third most common cause of death in Hong Kong with CHD being the largest contributor to the statistics at 66.6% of all heart diseases deaths. (2) The term “Heart Disease” comprise a wide range of diseases that affect the heart while “Coronary Heart Disease” refers to the disease of the coronary arteries that supply the heart. This occurs when the coronary arteries that supply oxygen to the heart narrows due to cholesterol deposits in the inner walls, affecting the oxygen flow to the cardiac muscle leading to arm and chest pain or in severe cases, a heart attack. (2,3)
Non-communicable diseases (NCD) include heart disease, diabetes, cancer and chronic respiratory disease, is a global burden to the human population according to WHO, making up 70% of all global deaths and 55% of all registered deaths in Hong Kong. Given a health-positive physical and social environment, a third of these cases can be prevented through lifestyle choices. The primary lifestyle choice that we will focus on in this article, is physical inactivity, which also remains a public health issue. (4) Physical inactivity is a primary factor for ischemic heart disease (30%) and is a risk factor for heart diseases (4,5)
According to Japan’s Exercise and Physical Activity Guide for Health Promotion in 2006, physical activity, as a general term, is described as bodily movements that require a higher level of energy expenditure than the resting energy expenditure. They categorised physical activity to “Exercise” and “Non-Exercise Activity” (NEA). Exercise is a purposeful physical activity that is done repetitively to maintain one’s physical fitness such as jogging, swimming and cycling. NEA, on the other hand are physical activities that are not regarded as physical activity such as playing with children, walking to work and gardening. This also includes occupations that require you to be physically active such as tour guides, teachers and surgeons . (6)
The recommendation by the World Health Organisation (WHO) states that adults aged 18 or above should perform at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity aerobic activity or an equivalent combination of moderate and vigorous-intensity aerobic activity per week. Exercise should be performed at least 30 minutes a day, on most days and it can be divided into bouts of at least 10 minutes each time, 3 times per day. (9) The intensity of the physical activity can be measured by METs, which are units of metabolism. For example, at rest, a person will spend 1 METs of energy to maintain normal body functions. (8)
Please refer to the compendium of physical activity by Ainsworth and colleagues for a wide range of physical activities and their METs reference value. *
Based on scientific research, there is strong evidence that shows a dose-response relationship with the frequency, intensity, duration and volume of physical activity and risk of cardiovascular disease. To lower cardiovascular risk significantly, the evidence suggests that at least 150 minutes per week of moderate to vigorous intensity physical activity is required.. (9) Furthermore, dynamic aerobic endurance training evidently lowered blood pressure in certain hypertensive groups with a reduction of 8 to 10 mm Hg in both systolic and diastolic blood pressure readings. (11) All-cause mortality, meaning the death rate from all causes of death, including heart disease mortality also seems to be lower for those who are physically active. The recommendations on physical exercise training by Canadian Medical Association Journal supports this evidence by giving a grade A recommendation for those who do not have hypertension but have established atherosclerotic disease to become physically active to reduce the risk of cardiovascular disease mortality, re-infarction and from other causes. (8)
Here are some general guidelines to start exercising when you have heart disease. It is best to speak to your healthcare provider before you start any exercise program. The general recommendation is to start slow and choose a low-impact aerobic exercise such as swimming, jogging or cycling at least 3-4 times each week. It is recommended that the exercise training program into 3 periods: warm up, training and cool down, a proper warm up and cool down (at least 5 minutes of light intensity) can have a protective effect on the heart. People with heart disease should be more aware of the weather when exercising outdoors, whether it is too cold or too hot and dress accordingly. Hydration is an important factor as well, it is advisable to always carry a water bottle to rehydrate when necessary. Resistance training and weight training are also recommended to improve the musculoskeletal system, providing overall health benefits. The key is to start slow with minimal repetition. As with all exercises, It is essential to listen to one's body and take sufficient rest time whenever necessary. Medical attention should be sought when these alarm signs are present; worsening of heart disease, numbing, shortness of breath and lightheadedness. (12,13)
Given extensive evidence on the benefits of exercise, there are remaining safety concerns regarding exercise for this population and the risk of a cardiovascular event during exercise. Studies have shown that, compared to otherwise healthy individuals, the risk is higher for those with heart diseases. However, the absolute incidence of death during exercise is relatively low. Musculoskeletal injuries, on the other hand, are common, as with repetitive exercises. (7,8) As a general note, a medical evaluation by the individual’s physician and exercise professional, and pre-participation screening should be performed adequately by trained exercise professionals to identify problem areas and high-risk individuals. In addition, the training and preparedness of exercise professionals in emergencies are essential and must meet industry standards. In conclusion, the overall health benefits of exercise outweigh the potential risk of exercise, which can be reduced significantly through pre-participation screening, medical evaluation and through the guidance of a trained exercise professional. (7)
Image Reference: (13) Recommendations for Prescribing Exercise to Patients with Heart Disease 8 8 Recommendations for Prescribing Exercise to 8 Patients with Heart Disease. (n.d.). [online] Available at: https://www.chp.gov.hk/archive/epp/files/DoctorsHanbook_ch8.pdf.
REFERENCE: (1) Janus, E.D., Postiglione, A., Singh, R.B. and Lewis, B. (1996). The Modernization of Asia. Circulation, 94(11), pp.2671–2673.
(2).Chp.gov.hk. (2019). Centre for Health Protection, Department of Health - Heart Diseases. [online] Available at: https://www.chp.gov.hk/en/healthtopics/content/25/57.html.
(3)Endler, N.S. (2001). Coronary Heart Disease (CHD), Coping with. [online] ScienceDirect. Available at: https://www.sciencedirect.com/science/article/pii/B0080430767038110 [Accessed 19 Aug. 2020].
(4) TOWARDS 2025 Strategy and Action Plan to Prevent and Control Non-communicable Diseases in Hong Kong Summary Report. (n.d.). [online] Available at: https://www.chp.gov.hk/files/pdf/saptowards2025_summaryreport_en.pdf [Accessed 19 Aug. 2020].
(5)HONG, YULING & Bots, Michiel & PAN, XINWEI & WANG, HUIZHEN & JING, HUAIGEN & Hofman, Albert & CHEN, HAOZHU. (1994). Physical Activity and Cardiovascular Risk Factors in Rural Shanghai, China. International Journal of Epidemiology. 23. 10.1093/ije/23.6.1154.
(6) Exercise and Physical Activity Guide for Health Promotion 2006. (2006). [online] Available at: https://www.nibiohn.go.jp/files/exercise_guide.pdf [Accessed 19 Aug. 2020].
(7)Balady, G.J., Chaitman, B., Driscoll, D., Foster, C., Froelicher, E., Gordon, N., Pate, R., Rippe, J. and Bazzarre, T. (1998). Recommendations for Cardiovascular Screening, Staffing, and Emergency Policies at Health/Fitness Facilities. Circulation, 97(22), pp.2283–2293.
(8)Cleroux, J., Feldman, R. and Petrella, R. (1999). Lifestyle modifications to prevent and control hypertension. 4. Recommendations on physical exercise training. Canadian Hypertension Society, Canadian Coalition for High Blood Pressure Prevention and Control, Laboratory Centre for Disease Control at Health Canada, Heart and Stroke Foundation of Canada. CMAJ: Canadian Medical Association Journal, [online] 160(9), pp.S21–S28. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1230336/.
(9) Information, N.C. for B., Pike, U.S.N.L. of M. 8600 R., MD, B. and Usa, 20894 (2010). EXECUTIVE SUMMARY. [online] www.ncbi.nlm.nih.gov. World Health Organization. Available at: https://www.ncbi.nlm.nih.gov/books/NBK305060/#ch1.s1 [Accessed 19 Aug. 2020].
(10) Cornelissen VA, Fagard RH. Effects of endurance training on blood pressure, blood pressure-regulating mechanisms, and cardiovascular risk factors. Hypertension. 2005;46(4):667-675. doi:10.1161/01.HYP.0000184225.05629.51
(11) Fletcher, G.F., Balady, G., Blair, S.N., Blumenthal, J., Caspersen, C., Chaitman, B., Epstein, S., Froelicher, E.S.S., Froelicher, V.F., Pina, I.L. and Pollock, M.L. (1996). Statement on Exercise: Benefits and Recommendations for Physical Activity Programs for All Americans. Circulation, 94(4), pp.857–862.
(12) Medlineplus.gov. (2014). Being active when you have heart disease: MedlinePlus Medical Encyclopedia. [online] Available at: https://medlineplus.gov/ency/patientinstructions/000094.htm.
(13) Recommendations for Prescribing Exercise to Patients with Heart Disease 8 8 Recommendations for Prescribing Exercise to 8 Patients with Heart Disease. (n.d.). [online] Available at: https://www.chp.gov.hk/archive/epp/files/DoctorsHanbook_ch8.pdf.