The narrowness of coronary arteries due to a gradual build-up of fatty material within their walls (atherosclerosis) is known as Coronary Heart Disease (CHD). Resistance training (RT) is an exercise that causes muscle contraction against the external resistance with the likelihood of increases in strength, tone, mass, and endurance. These types of exercises include push-ups, sit-ups, squat thrust and more. Muscles get thicker when we exercise, including the heart. Thicker muscle can contract forcefully without working harder and putting any stress to the heart during intensive exercise.
Despite its benefits, RT was not endorsed as an appropriate intervention for the prevention of cardiovascular disease risk factor for many years (med sci sports exercise, 1989). Early studies investigating the benefits of RT on CHD reported negligible improvement. The RT protocols utilised in these early studies, however, were performed mainly for strength development and muscle hypertrophy. It required the use of heavier loads (>70% of the subjects’ one-repetition maximum) and <10 repetitions. Later research then revealed that resistance training performed with a lighter load and higher repetitions does have a beneficial effect on risk factors—such as reducing plasma glucose and insulin levels, increasing high-density lipoprotein (HDL) cholesterol levels, and lowering resting blood pressure—without altering cardiovascular function in healthy subjects (Adams et al., 2006)

After a myocardial infarction (MI), physicians gave conflicting advice to their patients about the level of exercise they should practice; most are told not to lift anything >5 pounds. PhD students from Baylor University Medical Center conducted an informal survey of 28 patients from the Cardiac Rehabilitation Department at Baylor Jack and Jane Hamilton Heart and Vascular Hospital and collected the following;

Not to lift >10 pounds, not to drive for more than 30 minutes, not get exhausted for about a month, not to exercise for a few weeks, and not to lift >25 pounds for some time or ever. Although the size of the survey is not representative, the physician’s advice still promotes fear and inactivity to cardiac patients. Moreover, While physicians now acknowledge the value of exercise in cardiac rehabilitation, they have been hesitant to allow resistance training. Part of the problem is the existing guidelines (table 1) (Adams et al., 2006).

These guidelines for RT in cardiac rehabilitation are overly restrictive, limiting cardiac patients from achieving their desired levels of daily activity after a cardiac event. The study that was examined by Adams et al., 2006, looks at the illogical nature of the existing guidelines compared to the daily activities of patients (table 2). According to the study, opening the door to a cardiac rehabilitation facility required equivalent strength to lifting 15.5-pounds, meaning that patients could not even open the door to the CR facility. Most basic daily activities require strength, and being confident in practising these activities is beneficial to patients.

Source: Adams et al., (2006). Importance of Resistance Training for patients after a Cardiac Event.

Department of Physical Education, University of California, Davis performed critical studies to assess the safety and efficacy of RT. The study involved nine aerobically trained male Cardiac patients. These cardiac patients had to lift 80% of Maximum Voluntary Contraction (MVC) at five stations: quadricep extension, standing bisect curls, bench presses, hamstring curls and military press and performing 80 % of the maximum number of sit-ups in 60 seconds. MVC for each lift and body composition via bodyweight, hydrostatic weighing, skinfold and girth were verified before and after training. Electrocardiogram was controlled during all MVC lifts and heart rate, and systolic and diastolic blood pressure were monitored during all activities. The patients did these activities for 30 min/day, 3 days/week, 10-week strength training program. The recorded results were as follows:

Body composition: 11 % increase in quadriceps,(p<0.005), only.

MVC: increased 17, 12, 19, 53 and 46% for bench press, military press, standing biceps curls, quadriceps extension and hamstring curls, respectively (p <  0.01), while the number of sit-ups performed in 60 seconds increased 33% (p < 0.05). There were no symptoms of ischemia or abnormal heart rate or blood pressure responses observed during the RT program. Thus, resistive training at 80% of maximum voluntary contraction appears to be both safe and efficacious in stable, aerobically trained cardiac patients (Ghilarducci LE, 1989).

 

Unfortunately, the resistance exercise protocols used in these studies did not consider the age range and gender; therefore, more studies in a larger group of people are needed for a reliable conclusion.Nevertheless, supporting evidence was provided by Fahlman et al., 2002 who conducted exercise interventions for ten weeks to examine the effects of RT and aerobic training (AT) on plasma lipoprotein levels in older women who were active but nonexercising before the study. NB: For the purpose of this page, only RT protocols and results will be analysed. Total of 30 healthy, active women, aged 70–87 years, were randomly assigned to either RT (RT, 73 ± 3 years, n = 15) or control (C, 74 ± 5 years, n = 15) group. The exercise training session for the RT group consisted of one to three sets of eight repetitions of eight different exercises at an eight repetition maximum; the C group maintained regular activity. Weight were unchanged across groups. Samples of blood were collected from all participants at week 0 and week 11.

RT groups had increased HDL cholesterol and decreased triglycerides at week 11 compared with week 0. No positive changes in control lipoprotein were recorded. Both triglycerides and the total cholesterol to HDL ratio increased significantly while total cholesterol, HDL cholesterol, and LDL cholesterol remained unchanged, Compared to the control group, the RT group showed significantly lower LDL cholesterol and total cholesterol at week 11. Therefore RT resulted in favourable changes to plasma lipoprotein levels for older women in only ten weeks (Fahlman et al., 2002). The prevalence of CHD correlates directly with plasma concentration of LDL and inversely with HDL (Castelli et al. 1977; Kannel et al. 1979) thus RT could lower the risk of CHD by lowering plasma concentration of LDL. However, the results of these studies should be cautioning because of inadequate control of other factors such as diet and age group. Correlation is not causation; therefore, this experiment lacks some evidence that would prove of RT in reducing the risk to CHD directly. More studies and exterminates needs to conducted for further factual conclusions.

 

 

Source (table 3,4 and 5): Flynn et al., (2002). Effects of Endurance Training and Resistance Training on Plasma Lipoprotein Profiles in Elderly Women.

References:
HURLEY, B. (1989). Effects of resistive training on lipoprotein lipid profiles. Medicine

& Science in Sports & Exercise, 21(6), p.689.
Adams, J., Cline, M., Reed, M., Masters, A., Ehlke, K. and Hartman, J. (2006).

Importance of Resistance Training for Patients After a Cardiac Event.

Ghilarducci LE, e. (1989). Effects of high resistance training in coronary artery disease. – PubMed – NCBI. [online] Ncbi.nlm.nih.gov. Available at: https://www.ncbi.nlm.nih.gov/pubmed/2801553 [Accessed 12 Dec. 2019].

cline, M., Cline, M., Reed, M., Masters, A., Ehlke, K. and Hartman, J. (2006).Importance of Resistance Training for Patients After a Cardiac Event.

Fahlman, M., Boardley, D., Lambert, C. and Flynn, M. (2002). Effects of Endurance Training and Resistance Training on Plasma Lipoprotein Profiles in Elderly Women.The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 57(2), pp.B54-B60.

Castelli, W. (1977). HDL cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study. – PubMed – NCBI. [online] Ncbi.nlm.nih.gov. Available at: https://www.ncbi.nlm.nih.gov/pubmed/191215 [Accessed 13 Dec. 2019].