Exercise duration as a determinant of vascular function and antioxidant balance in patients with coronary artery disease

Abstract

Exercise had no effect on aortic and radial BP (p=NS for all). Walking for 30 min improved AIx (from 33.79 ± 0.91% to 31.73 ± 0.86%, p<0.001) and PWV (from 9.26 ± 0.95 m/s to 9.06 ± 0.21 m/s, p<0.001), while exercise for 60 min had adverse effects on vascular stiffness (for AIx: from 33.37 ± 0.93% to 33.73 ± 1.05%, p=NS and for PWV: from 9.25 ± 0.19 m/s to 9.37 ± 0.21 m/s, p < 0.05 mainly in older patients). Exercise for 60 min was associated with a significant 20% increase in MDA levels (p<0.05). Exercise had no effects on SOD1 levels, however it significantly increased SOD2 levels after 30 min (from 2.26 ± 0.22 ng/mL to 2.36 ± 0.18 ng/mL, p < 0.05) but not after 60 min (p=NS). Conclusion Shorter exercise duration was associated with favourable antioxidant and vascular effects, while longer exercise blunted these beneficial effects and was accompanied by adverse effects on vascular function, mainly in older coronary patients. Further studies are required to explore the hypothesis that a more individualised approach to the selection of the appropriate exercise programme should be considered for patients with CAD.

Potential Adverse Cardiovascular Effects From Excessive Endurance Exercise

“…8,24 The running rats developed hypertrophy of the left ventricle (LV) and the right ventricle (RV), diastolic dysfunction, and dilation of the left atria and the right atria (RA); they also showed increased collagen deposition and fibrosis in both the atria and ventricles (Figure 2). Ventricular tachycardia was inducible in 42% of the…”

“…The 30-minute exercise sessions produced less oxidant stress and improved arterial elasticity, whereas 60-minute sessions worsened oxidant stress and increased vascular stiffness as measured by pulse wave velocity, mainly in older patients. 8 Thus, the benefits of ET are attainable with comparatively modest levels of PA. Highly trained endurance athletes often perform strenuous aerobic exercise for several hours daily, often accumulating workloads of 200 to 300 metabolic equivalent hours (metabolic equivalents ϫ hours) per week, which is approximately 5-to 10-fold greater than the standard ET dose recommended for prevention of CHD.…”

Impact of cardiac rehabilitation and exercise training programs in coronary heart disease

“…Michaelides and colleagues found that 30 minutes of ET increased vascular elasticity and improved antioxidant balance; however, these benefits were lost when the ET duration was extended to 60 minutes. 61 These and other recent data suggest that when applied to vigorous ET, more moderate amounts of ET may provide added benefits at reduced risk (<5 hours of ET per week). 62,63 These physiologic findings appear to be supported by a cohort study of ~13,000 men and women conducted by Blair et al In it, the authors noted a plateau in benefits above 9-10 metabolic equivalents above which adjusted all-cause mortality no longer improved.…”

Exercising for Health and Longevity vs Peak Performance: Different Regimens for Different Goals

“…In contrast, the 60-minute sessions amplified oxidant stress and transiently stiffened blood vessels, especially among men older than 50 years. 29 A weekly cumulative dose of vigorous exercise of not more than about 5 hours has been identified in several studies to be the safe upper range for long-term CV health and life expectancy. [2][3][4][10][11][12][13]20,29 It may also be beneficial to take 1 or 2 days a week off from vigorous exercise and to refrain from high-intensity exercise on a daily basis.…”

“…[2][3][4]13,20 This recommendation is reinforced by a trial of 60 men with stable CHD who were randomized to vigorous exercise sessions lasting either 30 or 60 minutes. 29 The 30-minute exercise bouts enhanced arterial elasticity and generated minimal oxidant stress. In contrast, the 60-minute sessions amplified oxidant stress and transiently stiffened blood vessels, especially among men older than 50 years.…”