Multivariate analysis of the prognostic determinants of the depressor response to exercise therapy in patients with essential hypertension

Effect of exercise training on the renin-angiotensin-aldosterone system: a meta-analysis

Blood pressure (BP) management reduces the risk of cardiovascular disease (CVD). The renin-angiotensin-aldosterone system (RAAS) plays an important role in regulating and maintaining blood volume and pressure. This analysis aimed to investigate the effect of exercise training on plasma renin, angiotensin-II and aldosterone, epinephrine, norepinephrine, urinary sodium and potassium, BP and heart rate (HR). We systematically searched PubMed, Web of Science, and the Cochrane Library of Controlled Trials until 30 November 2022. The search strategy included RAAS key words in combination with exercise training terms and medical subject headings. Manual searching of reference lists from systematic reviews and eligible studies completed the search. A random effects meta-analysis model was used. Eighteen trials with a total of 803 participants were included. After exercise training, plasma angiotensin-II (SMD -0.71; 95% CI -1.24, -0.19; p = 0.008; n = 9 trials), aldosterone (SMD -0.37; 95% CI -0.65, -0.09; p = 0.009; n = 8 trials) and norepinephrine (SMD -0.82; 95% CI -1.18, -0.46; p < 0.001; n = 8 trials) were reduced. However, plasma renin activity, epinephrine, and 24-h urinary sodium and potassium excretion remained unchanged with exercise training. Systolic BP was reduced (MD -6.2 mmHg; 95% CI -9.9, -2.6; p = 0.001) as was diastolic BP (MD -4.5 mmHg; 95% CI -6.9, -2.1; p < 0.001) but not HR (MD -3.0 bpm; 95% CI -6.0, 0.4; p = 0.053). Exercise training may reduce some aspects of RAAS and sympathetic nervous system activity, and this explains some of the anti-hypertensive response.

Reduction of plasma aldosterone and arterial stiffness in obese pre- and stage1 hypertensive subjects after aerobic exercise

Obesity-related hypertension is associated with increased activity of the renin-angiotensin-aldosterone system (RAAS), increasing arterial stiffness. Aerobic exercise decreases pulse wave velocity (PWV), therefore a treatment option for hypertension and obesity. Assess RAAS activity and PWV before and after 4 weeks of aerobic training in unmedicated, pre-to-stage-1 hypertensives. Ten obese subjects (52±3.2 years, body mass index=33.5±1.4) performed 30 min of aerobic exercise on a treadmill 3 days per week at 65% of peak oxygen consumption (VO2peak). Descriptive characteristics, systolic and diastolic blood pressure (SBP and DBP), PWV, and a blood draw was performed at baseline, following the 4-week control and training interventions. No differences in descriptive characteristics during the control period were observed, however, a significant decrease in plasma aldosterone (ALDO) (255.4±75 to 215.8±66 pg ml(-1), P=0.001), SBP (140±12 to 136±10.4 mm Hg; P=0.02), DBP (89±4.2 to 85±6.3 mm Hg; P=0.03) and central PWV (11.2±0.6 to 9.8±0.8 m s(-1); P=0.04) was shown pre-to-post exercise training. Four weeks of moderate-intensity aerobic training in obese, hypertensives decreases plasma ALDO independently of body weight and is significantly correlated to decreases in PWV reductions.

Cardiac autonomic function and baroreflex changes following 4 weeks of resistance versus aerobic training in individuals with pre-hypertension

AIM

Cardiac autonomic modulation and baroreflex sensitivity (BRS) are altered in individuals with hypertension. Aerobic exercise (AE) training has been shown to improve both measures, yet little is known about the effects of resistance exercise (RE). The purpose of this study was to examine the heart rate variability (HRV) and BRS following 4 weeks of resistance or aerobic training in a population with borderline high blood pressure (BP).

METHODS

Twenty-nine mild hypertensives were recruited and randomly assigned to 4 weeks of RE or AE training. Before and after training, resting measures of HRV frequencies and BRS were obtained.

RESULTS

There was a significant decrease in resting systolic BP for both exercise training modes (RE 136 +/- 3.0 pre- to 132 +/- 3.4 post-training vs. AE 142 +/- 4.0 pre- to 137 +/- 3.6 mmHg post-training, P = 0.019). Diastolic BP decreased significantly following both exercise training modes (RE 78 +/- 1.31 pre to 74 +/- 1.1 post vs. AE 80 +/- 1.7 pre to 77 +/- 1.6 mmHg post, P = 0.002). A significant time by training mode interaction for low frequency : high frequency (HF) ratio (P = 0.017) with AE decreasing the ratio (275.21 +/- 67.28 to 161.26 +/- 61.49) and RE increasing this ratio (143.73 +/- 65.00 to 227.83 +/- 59.41). Natural log-transformed (ln) HRV values showed a time-by-training mode interaction for ln HF (P = 0.05) as ln HF increased (4.7 +/- 0.38 to 5.4 +/- 0.35 ms(2)) following AE and decreased (5.98 +/- 0.37 to 5.76 +/- 0.42 ms(2)) following RE. BRS increased following aerobic training and decreased after resistance training (6.74 +/- 1.2 to 7.94 +/- 1.3 and 10.44 +/- 1.2 to 9.1 +/- 1.2 ms mmHg(-1) respectively, P = 0.021).

CONCLUSIONS

Aerobic exercise improved the autonomic nervous system (increasing vagal tone, reducing sympathovagal balance while increasing BRS) while RE showed no improvements in cardiac autonomic tone and decreased BRS.

Effect of 4 weeks of aerobic or resistance exercise training on arterial stiffness, blood flow and blood pressure in pre- and stage-1 hypertensives

The benefits of aerobic exercise (AE) training on blood pressure (BP) and arterial stiffness are well established, but the effects of resistance training are less well delineated. The purpose of this study was to determine the impact of resistance vs aerobic training on haemodynamics and arterial stiffness. Thirty pre- or stage-1 essential hypertensives (20 men and 10 women), not on any medications, were recruited (age: 48.2 +/- 1.3 years) and randomly assigned to 4 weeks of either resistance (RE) or AE training. Before and after training, BP, arterial stiffness (pulse wave velocity (PWV)) and vasodilatory capacity (VC) were measured. Resting systolic BP (SBP) decreased following both training modes (SBP: RE, pre 136 +/- 2.9 vs. post 132 +/- 3.4; AE, pre 141 +/- 3.8 vs. post 136 +/- 3.4 mm Hg, P = 0.005; diastolic BP: RE, pre 78 +/- 1.3 vs post 74 +/- 1.6; AE, pre 80 +/- 1.6 vs. post 77 +/- 1.7 mm Hg, P = 0.001). Central PWV increased (P = 0.0001) following RE (11 +/- 0.9-12.7 +/- 0.9 ms(-1)) but decreased after AE (12.1 +/- 0.8-11.1 +/- 0.8 m s(-1). Peripheral PWV also increased (P = 0.013) following RE (RE, pre 11.5 +/- 0.8 vs. post 12.5 +/- 0.7 ms(-1)) and decreased after AE (AE, pre 12.6 +/- 0.8 vs post 11.6 +/- 0.7 m s(-1)). The VC area under the curve (VC(AUC)) increased more with RE than that with AE (RE, pre 76 +/- 8.0 vs. post 131.1 +/- 11.6; AE, pre 82.7 +/- 8.0 vs. post 110.1 +/- 11.6 ml per min per s per 100 ml, P = 0.001). Further, peak VC (VCpeak) increased more following resistance training compared to aerobic training (RE, pre 17 +/- 1.9 vs. post 25.8 +/- 2.1; AE, pre 19.2 +/- 8.4 vs post 22.9 +/- 8.4 ml per min per s per 100 ml, P = 0.005). Although both RE and AE training decreased BP, the change in pressure may be due to different mechanisms.

Sport therapy for hypertension: why, how, and how much?

Exercise may prevent or reduce the effects of metabolic and cardiovascular diseases, including arterial hypertension. Both acute and chronic exercise, alone or combined with lifestyle modifications, decrease blood pressure and avoid or reduce the need for pharmacologic therapy in patients with hypertension. The hypotensive effect of exercise is observed in a large percentage of subjects, with differences due to age, sex, race, health conditions, parental history, and genetic factors. Exercise regulates autonomic nervous system activity, increases shear stress, improves nitric oxide production in endothelial cells and its bioavailability for vascular smooth muscle, up-regulates antioxidant enzymes. Endurance training is primarily effective, and resistance training can be combined with it. Low-to-moderate intensity training in sedentary patients with hypertension is necessary, and tailored programs make exercise safe and effective also in special populations. Supervised or home-based exercise programs allow a nonpharmacological reduction of hypertension and reduce risk factors, with possible beneficial effects on cardiovascular morbidity.

Voluntary physical exercise and coronary flow velocity reserve: a transthoracic colour Doppler echocardiography study in spontaneously hypertensive rats

In the present study, we have developed and demonstrated a coronary artery imaging protocol in rats using transthoracic high-frequency CDE (colour Doppler echocardiography) to investigate the potential direct effects of exercise on CFVR (coronary flow velocity reserve). SHR (spontaneously hypertensive rats) performed voluntary exercise for 6 weeks. Rats were then submitted to ultrasonographic examination and CFVR measurements. The LAD (left anterior descending coronary artery) was visualized using transthoracic CDE in a modified parasternal long-axis view. Doppler measurement was made in mid-LAD during baseline and adenosine-induced hyperaemic condition. Gene and protein expression in cardiac tissue were studied using real-time PCR and immunohistochemistry. Adenosine infusion significantly (P<0.001, as determined by ANOVA) decreased HR, without affecting blood pressure in anaesthetized SHR. A significantly greater adenosine dose-dependent response was seen in exercised rats compared with controls (P=0.02, as determined by ANOVA). The baseline flow velocity in mid-LAD was 0.33±0.06 and 0.41±0.14 m/s in the exercised and control animals respectively (P value was not significant). The maximum adenosine-induced response was reached at a dose of 140 μg·kg−1 of body weight·min−1, and CFVR averaged at 2.6±0.53 and 1.5±0.24 in exercised and control animals respectively (P<0.01). Gene expression of CuZnSOD was up-regulated by 21% in exercised animals compared with controls (1.1±0.16 compared with 0.89±0.09; P<0.01), whereas eNOS expression was unchanged. In conclusion, CFVR in rats can be non-invasively assessed using CDE with high feasibility. Physical exercise is associated with improved CFVR and antioxidative capacity in SHR.