Intensity of swimming exercise influences aortic reactivity in rats

Abstract

Exercise is known to cause a vasodilatory response; however, the correlation between the vasorelaxant response and different training intensities has not been investigated. Therefore, this study evaluated the vascular reactivity and lipid peroxidation after different intensities of swimming exercise in rats. Male Wistar rats (aged 8 weeks; 250-300 g) underwent forced swimming for 1 h whilst tied to loads of 3, 4, 5, 6, and 8% of their body weight, respectively (groups G3, G4, G5, G6 and G8, respectively; n=5 each). Immediately after the test, the aorta was removed and suspended in an organ bath. Cumulative relaxation in response to acetylcholine (10−12-10−4 M) and contraction in response to phenylephrine (10−12-10−5 M) were measured. Oxidative stress was estimated by determining malondialdehyde concentration. The percentages of aorta relaxation were significantly higher in G3 (7.9±0.20), G4 (7.8±0.29), and G5 (7.9±0.21), compared to the control group (7.2±0.04), while relaxation in the G6 (7.4±0.25) and G8 (7.0±0.06) groups was similar to the control group. In contrast, the percentage of contraction was significantly higher in G6 (8.8 ±0.1) and G8 (9.7±0.29) compared to the control (7.1±0.1), G3 (7.3±0.2), G4 (7.2±0.1) and G5 (7.2±0.2%) groups. Lipid peroxidation levels in the aorta were similar to control levels in G3, G4 and G5, but higher in G6 and G8, and significantly higher in G8 (one-way ANOVA). These results indicate a reduction in vasorelaxing activity and an increase in contractile activity in rat aortas after high-intensity exercise, followed by an increase in lipid peroxidation.

Exercise for Prevention and Relief of Cardiovascular Disease: Prognoses, Mechanisms, and Approaches

“…In the spontaneous hypertension rats (SHR), exercise normalizes the increased collagen deposition and diminished fenestra size in the internal elastic lamina, meaning that exercise shows the benefit roles in normalizing the increased vascular stiffness and decreased vascular distensibility in both small mesenteric arteries and coronary arteries [48]. However, high-intensity exercise leads to the opposite effects that increased oxidative stress, elevated blood pressure, and high vasoconstrictor activity are found [49]. Some studies report that males tend to achieve greater reductions than females from the exercise training [50].…”

Exercise training improves vascular reactivity in ovariectomized rats subjected to myocardial infarction

“…Some studies have demonstrated that moderate to high-intensity ET provides greater benefits to cardiovascular and pulmonary functioning than lower intensity activities [35]. On the other hand, other studies reported vascular damage induced by the practice of high-intensity ET, such as a reduction in antioxidant enzymes, increase in contractility, and impairment of the relaxation [36,37].…”

Acute Aerobic Swimming Exercise Induces Distinct Effects in the Contractile Reactivity of Rat Ileum to KCl and Carbachol

“…They were acclimated 1 week before exercise, being subjected to periods of 10, 10, and 30 min of swimming exercise, three times a week during 1 week, in intercalated days, according to the protocol adapted from Chibalin et al ( 2000 ). The swimming protocol was adapted from Chies et al ( 2003 ) and Brito et al ( 2015 ). Briefly, the animals were submitted to forced swimming for 1 h with a metal of 3% of their body weight attached to them, to improve the animal's resistance and avoid floating in water, however maintaining the aerobic exercise as moderate intensity (Brito et al, 2015 ).…”

“…The swimming protocol was adapted from Chies et al ( 2003 ) and Brito et al ( 2015 ). Briefly, the animals were submitted to forced swimming for 1 h with a metal of 3% of their body weight attached to them, to improve the animal's resistance and avoid floating in water, however maintaining the aerobic exercise as moderate intensity (Brito et al, 2015 ). The exercise was performed in a plastic container measuring 43 cm width, 63 cm length, and 33 cm depth, with water at 24–27°C.…”