Stimulus Expectancy and Stimulus Response of Caffeine on 4-km Running Performance: A Randomized, Double-blind, Placebo-controlled and Crossover Study.

The placebo effect of caffeine has been poorly investigated in endurance exercise. Therefore, the aim of this study was to analyze the placebo effect of caffeine on 4 km running performance in amateur runners. Twenty-two healthy and recreational male runners (25.5 ± 8.4 yrs; 75.0 ± 7.1 kg; 173.7 ± 6.3 cm) underwent a deceptive experimental design consisting of three different sessions: a) control (CON) in which participants did not ingest any substance; b) placebo (PLA) in which participants ingested a capsule filled with maltodextrin but they were informed that they would receive caffeine; c) caffeine (CAF) in which participants were informed that they would receive caffeine and actually received caffeine. After 60 min for substances absorption, participants performed a 4-km test and they completed the distance as fast as possible. The time employed to cover the distance was lower in PLA (17.4 ± 1.5 min) and CAF (17.4 ± 1.4 min) than CON sessions (18.6 ± 2.8 min; P<0.05). There were no differences in the 4-km times between PLA and CAF (P>0.05) and no differences were reported between treatments for RPE (P>0.05). In conclusion, there was a placebo effect of caffeine on a 4-km maximal running trial which entailed that believing to have ingested caffeine improved performance to a similar extent than actually receiving caffeine. Therefore, the expectancy induced by caffeine may be one of the mechanisms behinds the ergogenic effect of this stimulant on endurance exercise.

Postexercise hypotension due to resistance exercise is not mediated by autonomic control: A systematic review and meta-analysis.

Changes in autonomic control have been suggested to mediate postexercise hypotension (PEH). We investigated through meta-analysis the after-effects of acute resistance exercise (RE) on blood pressure (BP) and autonomic activity in individuals with normal and elevated BP. Electronic databases were searched for trials including: adults; exclusive RE interventions; and BP and autonomic outcomes measured pre- and postintervention for at least 30 min. Analyses incorporated random-effects assumptions. Thirty trials yielded 62 interventions (N = 480). Subjects were young (33.6 ± 15.6 yr), with systolic BP (SBP)/diastolic BP (DBP) of 124.2 ± 8.9/71.5 ± 6.6 mm Hg. Overall, RE moderately reduced SBP (normal BP: ~1 to 4 mm Hg, p < 0.01; elevated BP: ~1 to 12 mm Hg, p < 0.01) and DBP (normal BP: ~1 to 4 mm Hg, p < 0.03; elevated BP: ~0.5 to 7 mm Hg, p < 0.01), which was in general parallel to sympathetic increase (normal BP: g = 0.49 to 0.51, p < 0.01; elevated BP: g = 0.41 to 0.63, p < 0.01) and parasympathetic decrease (normal BP: g = -0.52 to -0.53, p < 0.01; elevated BP: g = -0.46 to -0.71, p < 0.01). The meta-regression showed inverse associations between the effect sizes of BP vs. sympathetic (SBP: slope - 0.19 to -3.45, p < 0.01; DBP: slope - 0.30 to -1.60, p < 0.01), and direct associations vs. parasympathetic outcomes (SBP: slope 0.17 to 2.59, p < 0.01; DBP: slope 0.21 to 1.38, p < 0.01). In conclusion, changes in BP were concomitant to sympathetic increase and parasympathetic decrease, which questions the role of autonomic fluctuations as potential mechanisms of PEH after RE.

Moderators of strength gains and hypertrophy in resistance training: A systematic review and meta-analysis.

This meta-analysis investigated the role of resistance training (RT) moderators on strength and muscle mass gains in untrained young (YG) and older (OG) adults. Electronic databases were searched for randomised controlled trials simultaneously assessing muscle strength and mass. Effect sizes (ES) reflecting improvements in strength and muscle mass were found for all moderators in YG and OG (ES 0.25- to 1.72;p < 0.05), excepting muscle mass in YG after RT was performed with <3 sets/exercise. Strength gains (p < 0.001) were greater in non-periodised vs. periodised RT in YG (ES 1.72 vs. 1.05) and OG (1.40 vs. 0.74). ES in OG was greater (p < 0.04) when RT included non-failure vs. failure repetitions (1.35 vs. 0.96), 3 vs. >3 sets/exercise (1.30 vs. 0.90), ≥3 vs. <3 days/week (1.70 vs. 0.78), and ≥12 vs. <12 weeks (1.48 vs. 0.92). Amoderating effect of RT factors on muscle mass was not detected in YG, while greater ES was found in OG for RT with ≥3 vs. <3 days/week (0.50 vs. 0.25). Concluding, different combinations of RT factors improved strength and muscle mass in YG and OG. In OG, this was favoured by greater frequency and duration, although hampered by excessive volume.

Resistance training to reduce resting blood pressure and increase muscle strength in users and non-users of anti-hypertensive medication: A meta-analysis.

Objective: The aim of this study was to conduct a systematic review with meta-analysis to analyze the effect of resistance training variables prescription on resting systolic (SBP) and diastolic blood pressure (DBP) and muscle strength changes. Methods: The search was conducted in the PubMed, Web of Science, and SPORTDiscus databases until August 2020 for randomized controlled trials with non-exercising control group. Results: In total, 36 studies qualified for inclusion in this meta-analysis. Eleven studies included users of antihypertensive medication, while the remaining 25 studies were conducted with non-users of antihypertensive medication. Resistance training only reduced SBP (-0.56 [-0.77 to -0.35]; P < .001) and DBP (-0.46 [-0.68 to -0.24]; P < .001) in anti-hypertensive medication users, with changes ranging from -6.1 to -2.8 mmHg for SBP and -4.6 to -1.6 mmHg for DBP. Muscle strength increased significantly in both users (0.76 [0.49 to 1.02]; P < .001) and non-users of antihypertensive medication (0.94 [0.71 to 1.16]; P < .001). Resistance training should be performed by users and non-users of antihypertensive medication for 8 to 16 weeks (2 to 3 days a week) and 8 to 12 non-failure repetitions. However, users should train with less load (60-80 vs 70-85% 1RM) and exercise sets (1-3 vs 2-4) than non-users of antihypertensive medication. Conclusion: Resistance training increases muscle strength and reduces resting SBP and DBP in individuals under BP pharmacological therapy, while in individuals who do not use antihypertensive drugs, resistance training only increases strength.

Twelve weeks of resistance training performed with different number of sets: Effects on maximal strength and resting blood pressure of individuals with hypertension.

Objective: This study aimed to verify the effect of resistance training performed with single (SET1) or three sets (SET3) on muscle strength and resting blood pressure (BP) of individuals with hypertension. BP was also assessed during knee extension exercise with submaximal load before and after training. Methods: Thirty-eight patients with hypertension were randomly assigned to a control group (CON: n = 12; 55.6 ± 3.2 years; 65.3 ± 9.3 kg; 163.5 ± 8.6 cm), SET1 group (n = 14; 58.1 ± 2.0 years; 65.4 ± 8.7 kg; 162.4 ± 11.1 cm) or SET3 group (n = 12; 57.9 ± 2.4 years; 66.3 ± 11.4 kg; 161.6 ± 7.5 cm). The training was conducted for 12 weeks (3 d.w-1; 4 exercises; 12-15 repetitions; moderate intensity). Results: No differences were found in pre-training values for BP and strength between groups. After training, SET3 showed lower values than CON for resting systolic (121.3 ± 8.0 vs 129.3 ± 10.3 mmHg; P = .01) and diastolic BP (73.5 ± 6.0 vs 79.5 ± 7.4 mmHg; P = .02). Muscle strength in bench-press and knee extension exercises increased in SET1 (48.1 ± 6.3 and 71.3 ± 12.2 kg, respectively) and SET3 (50.2 ± 7.8 and 75.2 ± 9.6 kg, respectively) in relation to CON (39.3 ± 5.1 and 62.4 ± 9.9 kg) (P < .01). BP during knee extension (70% of one maximal repetition) did not differ between groups either before or after training. Conclusion: Resistance training with a single set could be interesting when there is a need to increase muscle strength without necessarily reducing resting BP. On the other hand, the performance of three sets increased muscle strength and reduced BP at rest in individuals with hypertension.

The effects of aerobic training on the CD4 cells, VO2max, and metabolic parameters in HIV-infected patients: a meta-analysis of randomized controlled trials.

INTRODUCTION: To our knowledge, there are no systematic review study with meta-analysis that investigated the influence of training variables on specific outcomes (CD4 cell counts) addressed aerobic training (AT) for HIV+ patients. In this sense, the purpose of this study was to perform a systematic review with meta-analysis of randomized controlled trials on AT in HIV+ patients and to analyze the influence of AT modulating variables on the CD4 cells, VO2max, and metabolic parameters. EVIDENCE ACQUISITION: Searches were performed in the databases PubMed, ISI Web of Knowledge, SportDiscus, Lilacs, Science Direct, and Scielo. EVIDENCE SYNTHESIS: Twelve studies involving 438 subjects (78.2% male) were included. Overall, the sample was sedentary (pre-training VO2max of 30.5 mL.kg-1.min-1) with a mean time of virus infection of 66.9 months and mean number of CD4 cells of 467.8 cells/mm3. AT increased the VO2max (ES=1050 [0.455 to 1.64]; P<0.001) and CD4 cell count (ES=0.402 [0.203 to 0.601]; P<0.001). AT for 8-12 weeks appears to be sufficient to increase VO2max, and the highest gains are associated with patients who present higher initial CD4 cell values. There was no difference to metabolic parameters. CONCLUSIONS: AT did not change the metabolic parameters, but it was AT is able to promote a greater magnitude of improvement in VO2max in the initial weeks of training and a greater increase in the number of CD4 cells in patients who present a better immune condition prior to training.

Improvement of Lower-Body Resistance-Exercise Performance With Blood-Flow Restriction Following Acute Caffeine Intake.

PURPOSE: To examine the effects of acute caffeine (CAF) intake on physical performance in 3 sets of unilateral knee extensions with blood-flow restriction. METHODS: In a double-blind crossover design, 22 trained men ingested 6 mg·kg-1 of CAF or a placebo (PLA), 1 h prior to performing unilateral knee-extension exercise with blood-flow restriction until exhaustion (30% of 1 maximal repetition). RESULTS: There was a significant difference in the number of repetitions between the CAF and PLA conditions in the first set (28.3 [5.3] vs 23.7 [3.2]; P = .005), second set (11.6 [3.1] vs 8.9 [2.9]; P = .03), and total repetitions performed across the 3 sets (44.5 [9.4] vs 35.0 [6.6]; P = .001). Blood lactate was also significantly different (P = .03) after exercise between the CAF (7.8 [1.1] mmol·L-1) and PLA (6.0 [0.9] mmol·L-1). In regard to pain perception, there was a difference between the CAF and PLA in the second (6.9 [1.5] vs 8.4 [1.4]; P = .04) and third sets (8.7 [0.4] vs 9.5 [0.6]; P = .01). No differences were found for perceived effort. CONCLUSION: Acute caffeine intake increases performance and blood lactate concentration and reduces perception of pain in unilateral knee-extension exercise with blood-flow restriction.

Blood pressure response between resistance exercise with and without blood flow restriction: A systematic review and meta-analysis.

AIM: The aim of this study was to compare, by means of a systematic review and meta-analysis, the effects of resistance training with and without blood flow restriction (BFR) on blood pressure (BP). MATERIALS AND METHODS: This review was composed according to the preferred Reporting items for Systematic Reviews and Meta-Analyses guidelines. Searches were carried out in the databases PubMed, SPORTDiscus, and Web of Science. BP was the main outcome for the analysis of the acute, post-exercise, and chronic effect of resistance exercise with and without BFR. Search results were limited to studies investigating the effect of resistance training with and without BFR on acute or chronic BP, published in a scientific peer-reviewed journal in English. KEY FINDINGS: Seventeen references were eligible. During exercise, the diastolic BP (DBP) was higher in exercise with BFR (ES = 17.84) in comparison to traditional exercise with loads ≥60% 1RM (ES = 5.53; P < 0.01); and the systolic BP (SBP) and DBP were higher during exercise with BFR in hypertensive individuals (ES = 69.83 and 43.66) in comparison to traditional exercise with loads <60% 1RM (ES = 48.05 and 28.37; P < 0.05). In the post-exercise analysis, exercise with BFR presented lower values for SBP (ES = -5.13; P = 0.02) and DBP (ES = -4.70; P < 0.01). SIGNIFICANCE: Although resistance exercise with BFR resulted in greater post-exercise hypotension than traditional exercise, higher SBP and/or DBP values were observed during exercise with BFR compared to traditional exercise, especially in hypertensive individuals. Thus, exercise with BFR should be prescribed with caution when BP control is necessary during exercise.

Acute Specific Effects of Caffeine-containing Energy Drink on Different Physical Performances in Resistance-trained Men.

Caffeine containing energy drink (ED) is frequently used as ergogenic aid, but its effect on performance need more investigation. Thus, the aim of this study was to analyze the effects of acute ingestion of an ED on the physical performance of resistance-trained men subjected to successive tests in the same experimental protocol. Fifteen resistance-trained males (21.0 ± 0.3 yrs; 177.4 ± 1.8 cm; 79.6 ± 1.8 kg) ingested 2.5 mg caffeine per kg of body weight (619.5 ± 14.6 mL of ED) or a placebo in a double-blind randomized cross-over design. Physical performance was randomized for the maximum repetition tests (80% 1RM) in the bench press exercise and unilateral knee extension (dominant leg), maximal isometric hand-grip test in both hands, standing long jump and repeated sprint ability test. The paired Student-t test showed that ED intake increased performance compared to the placebo for the number of repetitions in the unilateral knee extension test of the dominant leg (11.5 ± 0.9 reps vs 9.5 ± 0.8 reps; P = 0.001) and bench press (10.2 ± 0.4 reps vs 8.1 ± 0.5 reps; P = 0.01); and also increased isometric strength in the hand-grip maximal test in the right (53.7 ± 1.5 kg vs. 47.7 ± 1.6 kg; P = 0.02) and left hand (52.9 ± 1.5 kg vs. 45.9 ± 1.3 kg; P = 0.02). In conclusion, acute ingestion of ED increased performance only in specific strength tests in resistance-trained men.

Acute resistance exercise with blood flow restriction in elderly hypertensive women: haemodynamic, rating of perceived exertion and blood lactate.

PURPOSE: This study aimed to compare haemodynamic, rating of perceived exertion and blood lactate responses during resistance exercise with blood flow restriction (BFR) compared with traditional high-intensity resistance exercise in hypertensive older women. METHODS: Eighteen hypertensive women (age = 67·0 ± 1·7 years.) undertook three random sessions: (i) three sets; 10 repetitions; 20% of one repetition maximum (1RM) with BFR; (ii) three sets; 10 repetitions; 65% of 1RM; without BFR; and (iii) no-exercise with BFR. The exercise sessions were performed on knee extension equipment. RESULTS: Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV) and cardiac output (CO) were significantly higher (P<0·05) in all sets of exercise sessions than the control. No statistically significant differences were detected between exercise sessions. However, SBP, DBP and systemic vascular resistance were higher (P<0·05) and SV and CO were lower (P<0·05) during the rest intervals in the session with BFR. The perceived exertion was significantly higher (P<0·01) in the 1st (4·8 ± 0·4 versus 3·1 ± 0·3), 2nd (7·3 ± 0·4 versus 5·7 ± 0·4) and 3rd sets (8·6 ± 0·5 versus 7·5 ± 0·4) of the traditional high-intensity resistance exercise compared with the exercise with BFR. Blood lactate was higher (P<0·05) in the traditional high-intensity resistance exercise (6·2 ± 0·7 mmol) than in the exercise with BFR (4·5 ± 0·4 mmol). CONCLUSION: In comparison with high-intensity resistance exercise, low-intensity resistance exercise with BFR can elicit: (i) same haemodynamic values during exercise; (ii) lower rating of perceived exertion; (iii) lower blood lactate; (iv) higher haemodynamic demand during the rest intervals.

Angiotensin converting enzyme 2 polymorphisms and postexercise hypotension in hypertensive medicated individuals.

The renin-angiotensin aldosterone system (RAAS) is associated with diverse physiological responses and adaptations to exercise. The angiotensin converting enzyme (ACE) 2 has vasodilatory effects, which might be associated with the blood pressure (BP) responses to acute exercise. The aim of this study was to investigate the role of ACE2 polymorphisms in postexercise hypotension (PEH). Thirty-four medicated hypertensive (61·3 ± 1·7 years, 76·1 ± 2·7 kg, 160 ± 1·6 cm) men (n = 12) and women (n = 22), participated in a control and a moderate intensity exercise session in a randomized order. After both experimental sessions, they left the laboratory wearing an ambulatory BP device for 24-h monitoring. ACE2 polymorphisms (Int-1 and Int-3) were assessed by polymerase chain reaction. Over the course of 5-h monitoring, we observed a significant reduction in SBP and DBP following exercise in the AA/AG of the Int-1 polymorphism (p-interaction = 0·02 and 0·001, respectively), whereas this could not be found in the individuals homozygous G (p-interaction = 0·76 and 0·51, respectively). With regard to Int-3 polymorphism, individuals AA/AG showed a significant reduction in SBP following exercise (p-interaction <0·0001) but not for DBP (p-interaction = 0·06) whereas GG individuals showed only a significant reduction in DBP following exercise (p-interaction = 0·02). Our results suggest that ACE2 polymorphism could affect PEH; however, larger trials are needed to confirm our findings.

The influence of physical training status on postexercise hypotension in patients with hypertension: a cross-sectional study.

BACKGROUND: To date, few studies have analyzed postexercise hypotension (PEH) in hypertensive patients with different levels of physical fitness. AIM: Therefore, this study aimed to compare PEH in trained and sedentary hypertensive individuals. METHODS: Fifty-one well-controlled hypertensive patients of both sexes were assigned to a trained group [60.4±9.4 years; resting blood pressure (BP)=126.3±5.4/75.0±6.3 mmHg; VO2peak=27.3±4.6 ml kg/min] and 58 sedentary hypertensive patients of both sexes were assigned to a sedentary group (63.1±8.9 years; resting BP=134.1±4.2/82.9±5.8 mmHg; VO2peak=20.6±5.5 ml/kg/min). In a cross-sectional design, the individuals were randomized to perform an aerobic exercise session (treadmill; 40 min; 55% VO2peak) and a control session on two different days in the morning. After each session, participants wore an ambulatory BP device for 12 h. RESULTS: Although no significant differences were identified in BP after the control session, after the experimental session, the trained participants presented lower values than the sedentary participants for systolic (124.1±6.3 vs. 133.4±5.2 mmHg, P<0.01) and diastolic BP (73.1±4.4 vs. 85.5±6.4 mmHg, P<0.01) over the course of 12 h monitoring. For the trained participants, significant correlations were also identified (P<0.05) between the VO2peak and systolic (R=-0.68) and diastolic BP (R=-0.61) 12 h monitoring. CONCLUSION: In conclusion, the training level of hypertensive patients influences PEH.

Acute effects of caffeine-containing energy drinks on physical performance: a systematic review and meta-analysis.

PURPOSE: Caffeine-containing energy drinks (EDs) are currently used as ergogenic aids to improve physical performance in a wide variety of sport disciplines. However, the outcomes of previous investigations on this topic are inconclusive due to methodological differences, especially, in the dosage of the active ingredients and the test used to assess performance. METHODS: We performed a systematic review and meta-analysis of published studies to evaluate the effects of acute ED intake on physical performance. The search for references was conducted in the databases PubMed, ISI Web of Knowledge and SPORTDiscus until December 2015. RESULTS: Thirty-four studies published between 1998 and 2015 were included in the analysis. Using a random-effects model, effect sizes (ES) were calculated as the standardized mean difference. Overall, ED ingestion improved physical performance in muscle strength and endurance (ES = 0.49; p < 0.001), endurance exercise tests (ES = 0.53; p < 0.001), jumping (ES = 0.29; p = 0.01) and sport-specific actions (ES = 0.51; p < 0.001), but not in sprinting (ES = 0.14; p = 0.06). The meta-regression demonstrated a significant association between taurine dosage (mg) and performance (slope = 0.0001; p = 0.04), but not between caffeine dosage (mg) and performance (slope = 0.0009; p = 0.21). CONCLUSION: ED ingestion improved performance in muscle strength and endurance, endurance exercise tests, jumping and sport-specific actions. However, the improvement in performance was associated with taurine dosage.

Blood pressure and autonomic responses following isolated and combined aerobic and resistance exercise in hypertensive older women.

PURPOSE: This study aimed to compare blood pressure (BP) after isolated and combined sessions of aerobic and resistance exercises in hypertensive older women. Heart rate (HR) and heart rate variability (HRV) were included as additional variables. METHODS: Twenty-one older women (63±1.9 years; 69.9±2.7 kg; 158.8±2.1 cm) with controlled hypertension (resting BP = 132.2 ± 3.1/74.1 ± 4.0 mmHg) performed four random sessions on different days: 1) aerobic exercise (AE: treadmill walking/running; 40 min; 50-60% HRreserve); 2) resistance exercise (RE: 8 exercises; 3 sets; 15 reps; 40% 1RM)); 3) aerobic exercise followed by resistance exercise (A+R); 4); control (CON). BP, HR and HRV were measured at rest and during 180 min after the sessions. RESULTS: The AE and A+R sessions demonstrated significant decreases in SBP and DBP (30, 60, 120, and 180 min; P < 0.05) and increases in HR (30 and 60 min; P < 0.05) compared to the CON. The RE session demonstrated significant reductions compared to the CON only for DBP (120 and 180 min; P < 0.05). No significant differences were observed in HRV between resting and all sessions. CONCLUSION: All sessions that involved aerobic exercise (AE and A+R) caused postexercise hypotension in comparison to the CON, with no differences in HRV.

The blood pressure-lowering effect of a single bout of resistance exercise: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: Current exercise guidelines recommend aerobic types of exercises on most days of the week, supplemented with dynamic resistance exercise twice weekly. Whereas the blood pressure (BP)-lowering effects of a single session of aerobic exercise have been well studied, less is known about the hypotensive effect of a single bout of resistance exercise. OBJECTIVES: To evaluate the transient effect of resistance exercise on BP by means of meta-analytic techniques. METHODS: A systematic electronic search in Medline, Scientific Electronic Library Online (SciELO), Latin American and Caribbean Health Sciences Literature (LILACS), Elton B Stephens Company (EBSCO), EMBASE and SPORTDiscus was completed in March 2015 identifying randomised controlled trials investigating the effect of a single bout of resistance exercise on resting or ambulatory BP in healthy adults. A subsequent meta-analysis was performed. RESULTS: The meta-analysis involved 30 studies, 81 interventions and 646 participants (normotensive (n = 505) or hypertensive (n = 141)). A single bout of resistance exercise elicited small-to-moderate reductions in office systolic BP at 60 minutes postexercise [-3.3 (-4.0 to -2.6)/-2.7 (-3.2 to -2.1) mmHg (CI 95%)], 90 minutes postexercise [-5.3 (-8.5 to -2.1)/-4.7 (-6.9 to -2.4) mmHg (CI 95%)] and in 24-hour ambulatory BP [-1.7 (-2.8 to -0.67)/-1.2 (-2.4 to -0.022) mmHg (CI 95%)] compared to a control session. The reduction in office BP was more pronounced in hypertensive compared to normotensive individuals (p < 0.01), when using larger muscle groups (p < 0.05) and when participants were recovering in the supine position (p < 0.01). CONCLUSION: A single bout of resistance exercise can have a BP-lowering effect that last for up to 24 hours. Supine recovery and the use of larger muscle groups resulted in greater BP reductions after resistance exercise.

Haemodynamic responses during resistance exercise with blood flow restriction in hypertensive subjects.

PURPOSE: This study aimed to compare haemodynamic responses during resistance exercise with blood flow restriction (BFR) in hypertensive women. METHODS: Twelve hypertensive women undertook three random experimental sessions in the leg-press exercise: (i) Three sets, eight repetitions, 20% of one-repetition maximum (1 RM), with BFR; (ii) Three sets, 15 repetitions, 65% of 1 RM, without BFR; and (iii) three sets, 15 repetitions, 20% of 1 RM, without BFR. The BFR was performed using two sphygmomanometers adjusted to fit both thighs. Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were measured on a beat-to-beat continuous basis. RESULTS: When compared to the 20% without BFR, the session with BFR presented increased values in all sets for the variables SBP, DBP, CO and SVR, and in the 2nd and 3rd sets for HR. The session with BFR also presented increased values compared to the 65% of 1 RM in the 2nd and 3rd sets for the variables SBP, DBP and HR and in all sets for the variables CO and SVR. CONCLUSION: Low-intensity resistance exercise with BFR can initiate higher haemodynamic and cardiovascular values than traditional high-intensity resistance exercises in hypertensive women.

ACE polymorphisms and the acute response of blood pressure to a walk in medicated hypertensive patients.

HYPOTHESIS/INTRODUCTION: Polymorphisms of the angiotensin converting enzyme (ACE) gene can interfere with exercise-induced acute blood pressure (BP) reduction. This cross-over study investigated the acute effect of a single walk on BP and tested whether polymorphisms of the ACE gene might explain the variation in BP responses. MATERIALS AND METHODS: Thirty-four healthy medicated individuals were randomized to one control and one walking session at 60-75% of heart rate reserve. Subjects left the laboratory wearing an ambulatory BP monitor until waking the next morning. RESULTS: Overall, systolic BP was somewhat lower following the walking session (p=.06), which could be attributed to a consistently lower systolic BP for 5 h after exercise (p-interaction<.04) compared with control rest. Similarly, II/ID individuals had a lower systolic BP (p-interaction=.02) and diastolic BP (p-interaction<.01) for 5 h after walking compared with control rest. Among DD individuals, a single walk did not induce a reduction in BP (p-interaction>.05). CONCLUSIONS: Our results showed that postexercise hypotension can occur after a walk at moderate intensity in carriers of the I allele; we were not able to demonstrate this in DD individuals. Our results suggest that genetic variation in the ACE gene might affect the BP response to exercise, although more research is needed to confirm these findings.

Efeitos do treinamento físico sobre a pressão arterial, frequência cardíaca e morfologia de ratos hipertensos / Effects of physical training by blood pressure, heart rate and cardiac morphology in hypertensive rats

O objetivo desse estudo foi verificar o efeito da natação sobre as alterações morfológicas cardíacas e hemodinâmicas de ratos com hipertensão induzida por L-NAME. Quarenta ratos Wistar foram divididos nos grupos: controle sedentário (CS), controle treinado (CT), sedentário com L-NAME (LS) e treinado com L-NAME (LT). Os animais treinados realizaram natação por até 60 min durante quatro semanas. Os animais dos grupos L-NAME receberam 20 mg.kg-1 também durante quatro semanas. O grupo LS apresentou maiores valores de PAM (136,6±5,1 mmHg) comparado ao CS (107,1±1,8 mmHg). O grupo LT apresentou reduções na PAM comparado ao LS (121,2±1,4 e 136,6±5,1 mmHg, respectivamente). Por outro lado, os LT ainda permaneceram hipertensos comparados ao CT (121,0±1,4 e 107,1±1,8 mmHg, respectivamente). Em relação à FC, houve bradicardia de repouso para os animais treinados. Os grupos CS e CT não apresentaram alterações no peso relativo e absoluto do coração. Houve aumento do peso absoluto do coração para o grupo LS comparado ao CS e também se observou aumento para o peso relativo e absoluto do coração para o grupo LT comparado ao CT. A análise histológica demonstrou que o treinamento físico pode reduzir a quantidade de lesões provocadas pela administração crônica de LNAME. Conclui-se que a natação foi eficiente em reduzir a PAM de animais hipertensos, mas não reduziu em animais normotensos. Adicionalmente, o treinamento físico não promoveu hipertrofia cardíaca, mas a administração de L-NAME aumentou o peso absoluto e relativo do coração em animais sedentários e treinados...

The objective of this study was to investigate the effect of swimming on the cardiac morphological and hemodynamic changes in rats with hypertension induced by L-NAME.. Forty Wistar rats were divided into four groups: sedentary control (SC), trained control (TC), sedentary with L-NAME (LS) and trained with LNAME(LT). The animals in the training groups performed swimming lasting up to 60 min for four weeks. Animals in the L-NAME groups received 20 mg.kg-1 during four weeks. The results showed that animals in the LS group had higher mean arterial pressure (136.6±5.1 mmHg) compared to CS (107.1±1.8 mmHg).The LT group showed significant reductions in mean arterial pressure compared to LS (121.2±1.4 and 136.6±5.1 mmHg, respectively). On the other hand, the LT group animals still remained hypertensive compared to CT group (121.0±1.4 and 107.1±1.8 mmHg respectively). In relation to HR, was observed resting bradycardia for the trained animals. The groups CS and CT showed no changes in relative and absolute weight of the heart. An increase in the absolute weight of the heart to the LS group compared to the CS and also observed an increase in the relative and absolute weight for the LT group compared toCT. Histologic analysis showed that exercise training can reduce the amount of damage caused by chronicadministration of L-NAME. In conclusion, we observed that mild exercise was effective in reducing meanarterial pressure in hypertensive rats. Additionally, exercise training did not induced cardiac hypertrophy,but the L-NAME increase the absolute and relative weight of the heart in sedentary and trained rats...

Relação entre o sistema renina angiotensina e as respostas cardiovasculares promovidas pelo exercício físico / Relationship between the renin-angiotensin system and cardiovascular responses promoted by exercise training

Introdução e objetivos: o sistema renina angiotensina (SRA) apresenta importante função na homeostase do sistema cardiovascular, e a ativação da via clássica resulta na formação de angiotensina II, que leva ao aumento da pressão arterial (PA). No entanto, novos estudos tem evidenciado a ativação da via da angiotensina (1-7), a qual apresenta respostas contrárias a Angiotensina II e consequentemente reduz a PA. Considerando que o exercício físico interfere nas respostas cardiovasculares, este estudo teve o propósito de revisar a literatura quanto a possível relação do treinamento físico com o SRA.Métodos: o trabalho foi dividido em sessões de estudos que envolveram animais e estudos com seres humanos. A busca destes estudos foi realizada na base Medline e os principais critérios foram amostras com animais ou seres humanos e artigos publicados em inglês. Depois de aplicados os critériosde inclusão e exclusão, foram encontrados 12 artigos envolvendo animais e oito envolvendo seres humanos.Resultados: Os estudos demonstraram que existe uma relação entre o treinamento físico e o SRA,sendo que as respostas cardiovasculares observadas após o exercício físico pode apresentar alguma relação com o SRA. Além disso, estudos com seres humanos demonstraram que polimorfismos em alguns genes do SRA podem ser determinantes para as respostas cardiovasculares encontradas após o exercício físico.Considerações finais: Tendo em vista as recentes investigações que relacionam as respostas cardiovasculares após o exercício físico com o SRA, esta relação parece ser importante ao considerar os mecanismos responsáveis por promover determinadas respostas cardiovasculares após o exercício físico, como a hipotensão.

Introduction and Objective: The renin angiotensin system (RAS) has an important function in the homeostasis of cardiovascular system, and the activation of the classical pathway results in the formation of angiotensin II which will lead to increased blood pressure (BP). However, new studies have shown the activation of the angiotensin (1-7), which shows opposite responses to angiotensin II and consequently reduces the BP. Where as exercise interferes in cardiovascular responses, this study aimed to review the literature regarding the possible relationship of physical training with the RAS. Methods: The work was divided into sessions of studies involving animals and studies involving humans. Searches were performed in Medline database, and the main criteria were samples with animals or humans and articles published in English. After applied the inclusion and exclusion criteria, we selected 12 articles involving animals and 8 involving humans. Results: The studies involving animals and humans have shown that there is a relationship between physical training and RAS, and cardiovascular responses observed after exercise may have some relationship with the RAS. Furthermore, studies in humans have shown that polymorphisms in some genes of the RAS may also be crucial to the cardiovascular responses found after exercise. Conclusion: Given the recent research linking cardiovascular responses after exercise with the SRA, this relationship seems to be important to consider the mechanisms responsible for promoting certain cardiovascular responses after exercise, such as hypotension.