Aerobic Plus Resistance Training May Improve Coronary Artery Disease Outcomes

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Aerobic Plus Resistance Training May Improve Coronary Artery Disease Outcomes CME/CE

Authors and Disclosures

Laurie Barclay, MDDisclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.

Désirée Lie, MD, MSEdDisclosure: Désirée Lie, MD, MSEd, has disclosed no relevant financial relationships.

Laurie Scudder, MS, NP-CDisclosure: Laurie Scudder, MS, NP-C, has disclosed that she has owns stock, stock options, or bonds in & and Procter & Gamble.

Brande Disclosure: Brande has disclosed no relevant financial information.

August 27, 2008 — In patients with coronary artery disease, aerobic trainingcombined with resistance training (RT) improves many outcomes, according to the results of a randomized study reported in the September issue of Medicine & Science in Sports & Exercise.

"Combined...AT and...RT rehabilitation programs are rapidly becoming standard treatments for individuals with coronary artery disease," write Marzolini, from the University of Toronto in Ontario, Canada, and colleagues. "Although recommendations for the AT prescription are widely known, the RT prescription when combined with AT remains unclear. Recently established RT practice guidelines for patients with CAD [coronary artery disease] advocate the use of one set of six to ten exercises."

The objective of the study was to compare the effects of 1 set or 3 sets of RT combined with AT vs AT alone in 72 persons with coronary artery disease. Participants were randomly assigned to AT (5 days/week) or combined AT (3 days/week) with either 1 set (AT/RT1) or 3 sets (AT/RT3) of RT performed 2 days/week. Before and after 29 weeks of training, VO2 peak, ventilatory anaerobic threshold (VAT), strength and endurance, body composition, and adherence were assessed.

Training was completed by 53 participants (mean age, 61 ± 2 years). The difference between groups was not significant for the average increase from baseline in VO2 peak (L/minute), which was 11% for AT (P < .05), 14% for AT/RT1 (P < .01), and 18% for AT/RT3 (P < .001). VAT improved significantly from baseline only in the AT/RT3 group (P < .05). Compared with the AT group, the AT/RT3 group had greater gain in lean mass (1.5 vs 0.4 kg; P < .01). However, gains between AT/RT1 and AT were similar (P = .20).

Reduction in body fat occurred only in the combined AT/RT groups (P < .05). Compared with the AT-alone group, strength and endurance increased more in the AT/RT groups (P < .05). The AT/RT3 group had lower adherence to the number of sets performed vs the AT/RT1 group (P < .02).

"Combined AT + RT yields more pronounced physiological adaptations than AT alone and appears to be superior in producing improvements in VO2 peak, muscular strength and endurance, and body composition," the study authors write. "The data support the use of multiple set RT for patients desiring an increased RT stimulus which may further augment parameters that affect VO2 peak, VAT, lower body endurance, and muscle mass in a cardiac population."

Limitations of this study include inability to fully explain how randomization resulted in the AT/RT1 group having a significantly greater VAT, leg strength, and leg lean mass at baseline than the AT/RT3 group and the imbalance in diagnoses between groups; lack of a physically inactive control group; and graded exercise tests conducted on a cycle ergometer, whereas the aerobic exercise prescription included walking, limiting relevance to activities of daily living.

"The combination of RT and AT yields greater improvements in cardiovascular endpoints of exercise performance, skeletal muscle function, and body composition compared to AT alone, in spite of a 28% reduction in the actual AT training stimulus," the study authors conclude. "These data strongly support a combined training intervention in CAD patients, and supports the use of multiple-set RT for patients desiring an increased RT stimulus."

The Toronto Rehabilitation Institute and Ministry of Health funded this research. The study authors have disclosed no relevant financial relationships.

Med Sci Sports Exerc. 2008;40:1557-1564.

Learning Objectives for This Educational ActivityUpon completion of this activity, participants will be able to:

Compare the effect of aerobic training with and without resistance training on cardiovascular fitness and endurance in patients with coronary artery disease. Compare compliance with aerobic training with and without resistance training and the effect on lean body mass and body fat in patients with coronary artery disease.

Clinical Context

Combined AT and RT is becoming a standard of care for rehabilitation in patients with coronary artery disease and is believed to provide better gains in strength, body composition, and exercise performance as measured by VO2 peak and VAT than AT alone.

This is a study comparing AT with 1 (RT1) and 3 (RT3) sets of RT in patients with coronary artery disease to examine effects on exercise and cardiovascular fitness, muscle mass and strength, body fat, and adherence to the programs.

Study Highlights

Included were men and women with documented coronary artery disease who did not participate in more than 20 minutes of AT or RT more than twice weekly in the previous 6 months. Excluded were those with blood pressure of more than 160/110 mm Hg, inguinal hernia, diabetic retinopathy, pulmonary and musculoskeletal disease, and severe depression. Baseline testing was performed to assess VO2 peak, VAT, body composition, muscular strength, and endurance. All participants took part in AT 5 days per week in the first 5 weeks. After that, the combined group replaced 2 days with RT (either 1 set for the AT/RT1 group or 3 sets for the AT/RT3 group). Training continued for an additional 24 weeks, and supervision was given once a week, with the remaining activities performed at home or in the community. Patients kept detailed logs of each exercise session, noting distance walked or jogged, duration, rest periods, peak heart rate, Borg rating, and symptoms during exercise. The logs were used to monitor compliance. The number of repetitions, amounts of weights lifted, and sets performed were documented. The AT program consisted of 30 to 60 minutes of walking and/or jogging, starting with 1.6 km with an intensity of 60% of VO2 peak and progressing every 2 weeks to maintain an exercise heart rate equivalent to 80% of VO2 peak. There were 3 consecutive weekly RT classes at weeks 6, 7, and 8 with follow-up at weeks 12, 16, and 22. RT exercises included 3 for the lower body, 5 for the upper body, and 2 trunk-stabilizing exercises. Exercise testing was performed with use of a symptom-limited graded exercise test on a cycle ergometer with workload increased by 16.7 W every minute, and breath-by-breath gas samples were collected and averaged via a calibrated metabolic cart. Lean and percent fat were determined by dual energy x-ray absorptiometry for the arm, leg, and trunk. Local muscular endurance was estimated on a different day from strength. Of 65 men and 7 women who agreed to participate, 26% withdrew from the study, leaving 16 in the AT group, 19 in the AT/RT1 group, and 18 in the AT/RT3 group for final analysis. Mean age was 61 years; the majority of participants were men. The AT group had more men with coronary artery bypass grafting and fewer with percutaneous coronary intervention vs the AT/RT3 group, whereas the AT/RT3 group had more men with diabetes vs the AT/RT1 group, and the AT/RT1 group had greater total body mass vs the AT/RT3 group. VO2 peak increased for all 3 groups after 29 weeks of training, with an increase of 11%, 14%, and 18% for the AT, AT/RT1, and AT/RT3 groups, respectively (difference not significant). There was a weak association between change in VO2 peak and increase in lean body mass. The adherence rate was 74%, and the AT/RT3 group completed required RT sets less frequently than the AT/RT1 group. The AT group showed no significant improvement in strength. Isokinetic knee strength increased significantly for the AT/RT1 and AT/RT3 groups vs the AT group. Upper and lower body muscle endurance increased significantly in the combined AT/RT groups but not the AT group, with significant differences between the combined AT/RT groups and the AT group. The AT/RT3 group had an increase in lean body mass of 3 to 4 times vs the AT group (1.5 vs 0.4 kg). There was a significant reduction in body fat in the AT/RT1 and AT/RT3 groups (–2.0% and –2.7%) but not in the AT group, and 73% of the reduction was from the trunk. There were no significant differences among the 3 groups for total body mass, waist or hip circumference, or body mass index.

Pearls for Practice

AT combined with RT training vs AT alone is associated with improved cardiovascular fitness and muscle endurance. AT combined with RT training vs AT alone is associated with improved lean body mass and decreased body fat, but RT3 is associated with lower compliance than RT1.

http://www.medscape.com/viewarticle/579656_print

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