Effects of continuous vs. interval exercise training on blood pressure and arterial stiffness in treated hypertension

Exercise is an effective intervention for treating hypertension and arterial stiffness, but little is known about which exercise modality is the most effective in reducing arterial stiffness and blood pressure in hypertensive subjects. Our purpose was to evaluate the effect of continuous vs. interval exercise training on arterial stiffness and blood pressure in hypertensive patients. Sixty-five patients with hypertension were randomized to 16 weeks of continuous exercise training (n=26), interval training (n=26) or a sedentary routine (n=13). The training was conducted in two 40-min sessions a week. Assessment of arterial stiffness by carotid-femoral pulse wave velocity (PWV) measurement and 24-h ambulatory blood pressure monitoring (ABPM) were performed before and after the 16 weeks of training. At the end of the study, ABPM blood pressure had declined significantly only in the subjects with higher basal values and was independent of training modality. PWV had declined significantly only after interval training from 9.44 +/- 0.91 to 8.90 +/- 0.96 m s(-1), P=0.009 (continuous from 10.15 +/- 1.66 to 9.98 +/- 1.81 m s(-1), P-ns; control from 10.23 +/- 1.82 to 10.53 +/- 1.97 m s(-1), P-ns). Continuous and interval exercise training were beneficial for blood pressure control, but only interval training reduced arterial stiffness in treated hypertensive subjects. Hypertension Research (2010) 33, 627-632; doi:10.1038/hr.2010.42; published online 9 April 2010

Effects of Exercise Training on Myocardial Blood Flow Reserve in Patients With Heart Failure and Left Ventricular Systolic Dysfunction

Exercise training has been shown to be effective in improving exercise capacity and quality of life in patients with heart failure and left ventricular (LV) systolic dysfunction. Real-time myocardial contrast echocardiography (RTMCE) is a new technique that allows quantitative analysis of myocardial blood flow (MBF). The aim of this study was to determine the effects of exercise training on MBF in patients with LV dysfunction. We studied 23 patients with LV dysfunction who underwent RTMCE and cardiopulmonary exercise testing at baseline and 4 months after medical treatment (control group, n = 10) or medical treatment plus exercise training (trained group, n = 13). Replenishment velocity (0) and MBF reserves were derived from quantitative RTMCE. The 4-month exercise training consisted of 3 60-minute exercise sessions/week at an intensity corresponding to anaerobic threshold, 10% below the respiratory compensation point. Aerobic exercise training did not change LV diameters, volumes, or ejection fraction. At baseline, no difference was observed in MBF reserve between the control and trained groups (1.89, 1.67 to 1.98, vs 1.81, 1.28 to 2.38, p = 0.38). Four-month exercise training resulted in a significant increase in beta reserve from 1.72 (1.45 to 1.48) to 2.20 (1.69 to 2.77, p <0.001) and an MBF reserve from 1.81 (1.28 to 2.38) to 3.05 (2.07 to 3.93, p <0.001). In the control group, 13 reserve decreased from 1.51 (1.10 to 1.85) to 1.46 (1.14 to 2.33, p = 0.03) and MBF reserve from 1.89 (1.67 to 1.98) to 1.55 (1.11 to 2.27, p <0.001). Peak oxygen consumption increased by 13.8% after 4 months of exercise training and decreased by 1.9% in the control group. In conclusion, exercise training resulted in significant improvement of MBF reserve in patients with heart failure and LV dysfunction. (C) 2010 Elsevier Inc. All rights reserved. (Am J Cardiol 2010;105:243-248)

Aerobic Exercise Training-Induced Left Ventricular Hypertrophy Involves Regulatory MicroRNAs, Decreased Angiotensin-Converting Enzyme-Angiotensin II, and Synergistic Regulation of Angiotensin-Converting Enzyme 2-Angiotensin (1-7)

Aerobic exercise training leads to a physiological, nonpathological left ventricular hypertrophy; however, the underlying biochemical and molecular mechanisms of physiological left ventricular hypertrophy are unknown. The role of microRNAs regulating the classic and the novel cardiac renin-angiotensin (Ang) system was studied in trained rats assigned to 3 groups: (1) sedentary; (2) swimming trained with protocol 1 (T1, moderate-volume training); and (3) protocol 2 (T2, high-volume training). Cardiac Ang I levels, Ang-converting enzyme (ACE) activity, and protein expression, as well as Ang II levels, were lower in T1 and T2; however, Ang II type 1 receptor mRNA levels (69% in T1 and 99% in T2) and protein expression (240% in T1 and 300% in T2) increased after training. Ang II type 2 receptor mRNA levels (220%) and protein expression (332%) were shown to be increased in T2. In addition, T1 and T2 were shown to increase ACE2 activity and protein expression and Ang (1-7) levels in the heart. Exercise increased microRNA-27a and 27b, targeting ACE and decreasing microRNA-143 targeting ACE2 in the heart. Left ventricular hypertrophy induced by aerobic training involves microRNA regulation and an increase in cardiac Ang II type 1 receptor without the participation of Ang II. Parallel to this, an increase in ACE2, Ang (1-7), and Ang II type 2 receptor in the heart by exercise suggests that this nonclassic cardiac renin-angiotensin system counteracts the classic cardiac renin-angiotensin system. These findings are consistent with a model in which exercise may induce left ventricular hypertrophy, at least in part, altering the expression of specific microRNAs targeting renin-angiotensin system genes. Together these effects might provide the additional aerobic capacity required by the exercised heart. (Hypertension. 2011;58:182-189.).

The Carvedilol`s Beta-Blockade in Heart Failure and Exercise Training`s Sympathetic Blockade in Healthy Athletes during the Rest and Peak Effort

In recent years, beta-blocker therapy has become a primary pharmacologic intervention in patients with heart failure by blocking the sympathetic activity. To compare the exercise training`s sympathetic blockade in healthy subjects (athletes) and the carvedilol`s sympathetic blockade in sedentary heart failure patients by the evaluation of the heart rate dynamic during an exercise test. A total of 26 optimized and 49 nonoptimized heart failure patients in a stable condition (for, at least, 3 months), 15 healthy athletes and 17 sedentary healthy subjects were recruited to perform a cardiopulmonary exercise test. The heart rate dynamic (rest, reserve, peak and the peak heart rate in relation to the maximum predicted for age) was analyzed and compared between the four groups. The heart rate reserve was the same between optimized (48 +/- 15) and nonoptimized (49 +/- 18) heart failure patients (P < 0.0001). The athletes (188 +/- 9) showed a larger heart rate reserve compared to sedentary healthy subjects (92 +/- 10, P < 0.0001). Athletes and healthy sedentary reached the maximum age-predicted heart ratefor their age, but none of the heart failure patients did. The carvedilol`s sympathetic blockade occurred during the rest and during the peak effort in the same proportion, but the exercise training`s sympathetic blockade in healthy subjects occurred mainly in the rest.

Impact of gender on benefits of exercise training on sympathetic nerve activity and muscle blood flow in heart failure

We compared the effects of exercise training on neurovascular control and functional capacity in men and women with chronic heart failure (HF). Forty consecutive HF outpatients from the Heart Institute, University of Sao Paulo, Brazil were divided into the following four groups matched by age: men exercise-trained (n = 12), men untrained (n = 10), women exercise-trained (n = 9), women untrained (n = 9). Maximal exercise capacity was determined from a maximal progressive exercise test on a cycle ergometer. Forearm blood flow was measured by venous occlusion plethysmography. Muscle sympathetic nerve activity (MSNA) was recorded directly using the technique of microneurography. There were no differences between groups in any baseline parameters. Exercise training produced a similar reduction in resting MSNA (P = 0.000002) and forearm vascular resistance (P = 0.0003), in men and women with HF. Peak VO(2) was similarly increased in men and women with HF (P = 0.0003) and VE/VCO(2) slope was significantly decreased in men and women with HF (P = 0.0007). There were no significant changes in left-ventricular ejection fraction in men and women with HF. The benefits of exercise training on neurovascular control and functional capacity in patients with HF are independent of gender.

Correlation between CD34(+) and exercise capacity, functional class, quality of life and norepinephrine in heart failure patients

Background: A previous study associated CD34(+) levels with NYHA functional class in heart failure patients. The aim of this study was to correlate CD34(+) levels to exercise capacity, functional class, quality of life and norepinephrine in heart failure patients. Methods: Twenty three sedentary patients (52 +/- 7 years, 78% male) answered the Minnesota Living with Heart Failure Questionnaire and rested for 20 minutes before an investigator collect a blood sample. After this, patients performed a cardiopulmonary exercise test to determine the heart rate at anaerobic and ventilatory threshold and oxygen consumption at peak effort, at anaerobic and ventilatory threshold. One other blood sample was collected during the peak effort to investigate the norepinephrine and CD34(+) levels. Results: Rest percentage of CD34(+) did not show correlation with: left ventricle ejection fraction (r = 0.03, p = 0.888), peakVO(2) (r = 0.32, p = 0.13), VO(2) at anaerobic threshold (VO(2)AT) (r = 0.03, p = 0.86), VO(2) at ventilatory threshold (VO(2)VT) (r = 0.36, p = 0.08), NYHA functional class (r = -0.2, p = 0.35), quality of life (Minnesota) (r = -0.17, p = 0.42). CD34(+) did not show correlation, either, with: peak VO(2) (r = 0.38, p = 0.06), VO(2)AT (r = 0.09, p = 0.65), VO(2)VT (r = 0.43, p = 0.4), NYHA functional class (r = -0.13, p = 0.54), quality of life (r = 0.00, p = 0.99). Conclusions: CD34(+) levels did not correlate with exercise capacity, functional class, quality of life and norepinephrine. Percentage of CD34(+) levels did not increase during the cardiopulmonary exercise test in heart failure patients. (Cardiol J 2009; 16, 5: 426-431)

Effects of Exercise Training in Patients with Chronic Heart Failure and Sleep Apnea

Study Objectives: To test the effects of exercise training on sleep and neurovascular control in patients with systolic heart failure with and without sleep disordered breathing. Design: Prospective interventional study. Setting: Cardiac rehabilitation and exercise physiology unit and sleep laboratory. Patients: Twenty-five patients with heart failure, aged 42 to 70 years, and New York Heart Association Functional Class I-III were divided into 1 of 3 groups: obstructive sleep apnea (n = 8), central sleep apnea (n 9) and no sleep apnea (n = 7). Interventions: Four months of no-training (control) followed by 4 months of an exercise training program (three 60-minute, supervised, exercise sessions per week). Measures and Results: Sleep (polysomnography), microneurography, forearm blood flow (plethysmography), peak VO(2). and quality of life were evaluated at baseline and at the end of the control and trained periods. No significant changes occurred in the control period. Exercise training reduced muscle sympathetic nerve activity (P < 0.001) and increased forearm blood flow (P < 0.01), peak VO(2) (P < 0.01), and quality of life (P < 0.01) in all groups, independent of the presence of sleep apnea. Exercise training improved the apnea-hypopnea index, minimum O(2) saturation, and amount stage 3-4 sleep (P < 0.05) in patients with obstructive sleep apnea but had no significant effects in patients with central sleep apnea. Conclusions. The beneficial effects of exercise training on neurovascular function, functional capacity, and quality of life in patients with systolic dysfunction and heart failure occurs independently of sleep disordered breathing. Exercise training lessens the severity of obstructive sleep apnea but does not affect central sleep apnea in patients with heart failure and sleep disordered breathing.

Acute effects of continuous and interval aerobic exercise on 24-h ambulatory blood pressure in long-term treated hypertensive patients

Background: Despite antihypertensive therapy, it is difficult to maintain optimal systemic blood pressure (BP) values in hypertensive patients (HPT). Exercise may reduce BP in untreated HPT. However, evidence regarding its effect in long-term antihypertensive therapy is lacking. Our purpose was to evaluate the acute effects of 40-minute continuous (CE) or interval exercise (IE) using cycle ergometers on BP in long-term treated HPT. Methods: Fifty-two treated HPT were randomized to CE (n=26) or IE (n=26) protocols. CE was performed at 60% of reserve heart rate (HR). IE alternated consecutively 2 min at 50% reserve HR with 1 min at 80%. Two 24-h ambulatory BP monitoring were made after exercise (postexercise) or a nonexercise control period (control) in random order. Results: CE reduced mean 24-h systolic (S) BP (2.6 +/- 6.6 mm Hg, p-0.05) and diastolic (D) BP (2.3 +/- 4.6, p-0.01), and nighttime SBP (4.8 +/- 6.4, p < 0.001) and DBP (4.6 +/- 5.2 mm Hg, p-0.001). IE reduced 24-h SBP (2.8 +/- 6.5, p-0.03) and nighttime SBP (3.4 +/- 7.2, p-0.02), and tended to reduce nighttime DBP (p=0.06). Greater reductions occurred in higher BP levels. Percentage of normal ambulatory BP values increased after CE (24-h: 42% to 54%; daytime: 42% to 61%; nighttime: 61% to 69%) and IE (24-h: 31% to 46%; daytime: 54% to 61%; nighttime: 46% to 69%). Conclusion: CE and IE reduced ambulatory BP in treated HPT, increasing the number of patients reaching normal ambulatory BP values. These effects suggest that continuous and interval aerobic exercise may have a role in BP management in treated HPT. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

Effects of proportional assisted ventilation on exercise performance in idiopathic pulmonary fibrosis patients

Background: Patients with idiopathic pulmonary fibrosis (IPF) present an important ventilatory (imitation reducing their exercise capacity. Non-invasive ventilatory support has been shown to improve exercise capacity in patients with obstructive diseases; however, its effect on IPF patients remains unknown. Objective: The present study assessed the effect of ventilatory support using proportional, assist ventilation (PAV) on exercise capacity in patients with IPF. Methods: Ten patients (61.2 +/- 9.2 year-old) were submitted to a cardiopulmonary exercise testing, plethysmography and three submaximal. exercise tests (60% of maximum load): without ventilatory support, with continuous positive airway pressure (CPAP) and PAV. Submaximal tests were performed randomly and exercise capacity, cardiovascular and ventilatory response as well as breathlessness subjective perception were evaluated. Lactate plasmatic levels were obtained before and after submaximal. exercise. Results: Our data show that patients presented a limited exercise capacity (9.7 +/- 3.8 mL O(2)/kg/min). Submaximal. test was increased in patients with PAV compared with CPAP and without ventilatory support (respectively, 11.1 +/- 8.8 min, 5.6 +/- 4.7 and 4.5 +/- 3.8 min; p < 0.05). An improved arterial oxygenation and lower subjective perception to effort was also observed in patients with IPF when exercise was performed with PAV (p < 0.05). IPF patients performing submaximal exercise with PAV also presented a lower heart rate during exercise, although systolic and diastolic pressures were not different among submaximal tests. Our results suggest that PAV can increase exercise tolerance and decrease dyspnoea and cardiac effort in patients with idiopathic pulmonary fibrosis. (C) 2009 Elsevier Ltd. All rights reserved.

Exercise Reduces Effects of Creatine on Lung

We recently demonstrated that creatine supplementation increased some features of lung allergic sensitization in mice. On the other hand, other studies have shown that aerobic exercise inhibited allergic airway inflammation and remodeling. We hypothesized that aerobic exercise may decrease the exacerbatory effects of the creatine supplementation in a murine model of asthma. Balb/c mice were divided into six groups: Control, Creatine (Cr), Low Intensity Exercise + Creatine (Low + Cr), Ovalbumin (OVA), Ovalbumin + Creatine (OVA + Cr) and Ovalbumin + Creatine + Low Intensity Exercise (OVA + Cr + Low). OVA-sensitized groups were sensitized with OVA intraperitoneal injections (days 0, 14, 28, and 42). Aerosol challenge (OVA 1 %) and Cr treatment (0.5 g/kg/day) were initiated on Day 21 until Day 53. Low intensity exercise began on day 22 and was sustained until day 50. Low intensity exercise in the presence of creatine supplementation in sensitized mice resulted in a decreased number of eosinophils in BALF (p < 0.001) and in the airways (P < 0.001), and a decreased density of inflammatory cells positive to IL-4 (p < 0.001) and IL-5 (p < 0.001), airway collagen (p < 0.001) and elastic fibers (p < 0.001) content, airway smooth muscle thickness (p < 0.001) and bronchoconstriction index (p < 0.05) when compared with OVA + Cr group. These results suggest that aerobic exercise reduces the exacerbatory effects of creatine supplementation in chronically sensitized mice.

Resistance exercise and glycemic control in women with gestational diabetes mellitus

OBJECTIVE: The objective of the study was to evaluate the effect of a resistance exercise program with an elastic band on insulin requirement and glycemic control in patients with gestational diabetes mellitus (GDM). STUDY DESIGN: Sixty-four patients with gestational diabetes mellitus were randomly assigned into 2 groups: an exercise group (EG; n = 32) and a control group not submitted to the exercise program (CG; n = 32). RESULTS: A significant reduction in the number of patients who required insulin was observed in the EG (7/32) compared with the CG group (18/32) (P = .005). The percentage of time spent within the proposed target glucose range (of at least 80% of weekly measurements below the limits preestablished for the disease) was significantly higher in EG compared with the CG group (EG = 0.63 +/- 0.30; CG = 0.41 +/- 0.31; P = .006). CONCLUSION: The resistance exercise program was effective in reducing the number of patients with GDM who required insulin and in improving capillary glycemic control in this population.

Resistance Exercise Intensity Progression in Older Men

Our purpose was to examine possible influences of age on resistance exercise (RE) intensity progression in men. Twenty-four men, divided in young sedentary (YS; n = 10; 25.9 +/- 3.7 years), older sedentary (OS; n = 7; 67.4 +/- 5.2 years), and older runners (OR; n = 7; 71.3 +/- 3.0 years), underwent a 2 times-a-week RE program for 13 weeks. Muscle strength was assessed before and after training by 1-repetition maximum test. RE workloads were recorded for each exercise session, and increases of 5-10% were made whenever adaptation occurred. Muscle strength improved similarly in all groups after RE (P < 0.001). Relative RE intensity progression was not significantly different between YS and OS, except for a greater increase in calf raise relative workload observed in YS (P < 0.05). In contrast, OR displayed greater relative workload increase in 7 and 6 exercises than YS and OS, respectively (P < 0.05). The RE was safe as no injuries or major muscle pain were observed in either group. These results suggest that healthy sedentary older men are capable to exercise and increase RE intensity in the same way as young men, while physically active older men are capable to increase RE intensity in greater way than sedentary young and older men.

Benefits of exercise training in diabetic rats persist after three weeks of detraining

Regarding all benefits of exercise training, a question remains: how long are these benefits kept? This study evaluated the effect of 3-week detraining after 10 weeks of training in STZ-diabetic rats. Male Wistar rats were assigned into: sedentary controls, trained controls, trained-detrained controls. sedentary diabetic, trained diabetic and trained-detrained diabetic. Arterial pressure (AP) and heart rate (HR) were recorded by a data acquisition system. Baroreflex sensitivity (BRS) was evaluated by HR responses to AP changes induced by infusion of vasoactive drugs. Intrinsic heart rate (IHR), sympathetic tonus (ST) and vagal tonus (VT) were evaluated by pharmacological blockade with atenolol and atropine. Spectral analysis of systolic AP and HR variabilities (HRV) was performed to estimate autonomic modulation to the heart and vessels. Diabetes cardiovascular and autonomic dysfunctions were reversed by exercise training and partially maintained in the 3-week detraining period. In controls, training decreased AP and HR and improved BRS. changes that returned to baseline values after detraining. IHR and VT were improved in trained diabetic rats and remained in detrained diabetic ones. LF component of HRV decreased in trained control group. In diabetics. exercise training improved variance, and absolute LF and HF components of HRV. Only HF was maintained in detrained diabetic group. Moreover, there was an inverse relationship between plasma glucose and the absolute HF component of HRV. These changes probably determined the different survival rate of 80% in diabetic detrained and 51% in diabetic sedentary rats. (c) 2008 Elsevier B.V. All rights reserved.

Airway epithelium mediates the anti-inflammatory effects of exercise on asthma

Airway epithelium plays an important role in the asthma physiopathology. Aerobic exercise decreases Th2 response in murine models of allergic asthma, but its effects on the structure and activation of airway epithelium in asthma are unknown. BALB/c mice were divided into control, aerobic exercise, ovalbumin-sensitized and ovalbumin-sensitized plus aerobic exercise groups. Ovalbumin sensitization occurred on days 0, 14, 28, 42, and aerosol challenge from day 21 to day 50. Aerobic exercise started on day 22 and ended on day 50. Total cells and eosinophils were reduced in ovalbumin-sensitized group submitted to aerobic exercise. Aerobic exercise also reduced the oxidative and nitrosative stress and the epithelial expression of Th2 cytokines, chemokines, adhesion molecules, growth factors and NF-kB and P2X7 receptor. Additionally, aerobic exercise increased the epithelial expression of IL-10 in non-sensitized and sensitized animals. These findings contribute to the understanding of the beneficial effects of aerobic exercise for chronic allergic airway inflammation, suggesting an immune-regulatory role of exercise on airway epithelium. (C) 2011 Elsevier B.V. All rights reserved.

Baroreflex deficit blunts exercise training-induced cardiovascular and autonomic adaptations in hypertensive rats

P>1. Baroreceptors regulate moment-to-moment blood pressure (BP) variations, but their long-term effect on the cardiovascular system remains unclear. Baroreceptor deficit accompanying hypertension contributes to increased BP variability (BPV) and sympathetic activity, whereas exercise training has been associated with an improvement in these baroreflex-mediated changes. The aim of the present study was to evaluate the autonomic, haemodynamic and cardiac morphofunctional effects of long-term sinoaortic baroreceptor denervation (SAD) in trained and sedentary spontaneously hypertensive rats (SHR). 2. Rats were subjected to SAD or sham surgery and were then further divided into sedentary and trained groups. Exercise training was performed on a treadmill (five times per week, 50-70% maximal running speed). All groups were studied after 10 weeks. 3. Sinoaortic baroreceptor denervation in SHR had no effect on basal heart rate (HR) or BP, but did augment BPV, impairing the cardiac function associated with increased cardiac hypertrophy and collagen deposition. Exercise training reduced BP and HR, re-established baroreflex sensitivity and improved both HR variability and BPV. However, SAD in trained SHR blunted all these improvements. Moreover, the systolic and diastolic hypertensive dysfunction, reduced left ventricular chamber diameter and increased cardiac collagen deposition seen in SHR were improved after the training protocol. These benefits were attenuated in trained SAD SHR. 4. In conclusion, the present study has demonstrated that the arterial baroreflex mediates cardiac disturbances associated with hypertension and is crucial for the beneficial cardiovascular morphofunctional and autonomic adaptations induced by chronic exercise in hypertension.