Different humidity environments do not affect the subsequent exercise ability of college football players after aerobic high-intensity interval training

Previous studies have explored the effect of differing heat and relative humidity (RH) environments on the performance of multiple anaerobic high-intensity interval training (HIIT). Still, its impact on physiological responses and performance following aerobic HIIT has not been well studied. This study examined the effects of differing RH environments on physiological responses and performance in college football players following HIIT. Twelve college football completed HIIT under four different environmental conditions: (1) 25 °C/20% RH (Control group); (2) 35 °C/20% RH (H20 group); (3) 35 °C/40% RH (H40 group); (4) 35 °C/80% RH (H80 group). The heart rate (HR), mean arterial pressure (MAP), lactate, tympanic temperature (TT), skin temperature (TS), thermal sensation (TS), and rating of perceived exertion (RPE) were recorded continuously throughout the exercise. The heart rate variability (HRV): including root mean squared differences of the standard deviation (RMSSD)、standard deviation differences of the standard deviation (SDNN)、high frequency (HF), low frequency (LF), squat jump height (SJH), cycling time to exhaustion (TTE), and sweat rate (SR) were monitored pre-exercise and post-exercise. The HR, MAP, lactate, TT, Ts, TS, and RPE in the 4 groups showed a trend of rapid increase, then decreased gradually. There was no significant difference in HR, MAP, TT, or RPE between the 4 groups at the same time point (p > 0.05), in addition to this, when compared to the C group, the lactate, Ts, TS in the other 3 groups significant differences were observed at the corresponding time points (p < 0.05). The RMSSD, SDNN, HF, and LF levels in the 4 groups before exercise were not significantly different. The RMSSD and HF in the H40 and H80 groups were significantly decreased and other HRV indicators showed no significant difference after exercise. In sports performance measurement, the SJH and TTE were significantly decreased, but there was no significant difference in the 4 groups. The SR was no significant difference in the 4 groups after exercise. In conclusion, heat and humidity environments elicited generally greater physiological effects compared with the normal environment but did not affect sports performance in college football players.

Effect of exercise modalities on postexercise hypotension in pre- and postmenopausal women: a systematic review and meta-analysis

Hormonal changes associated with menopause increase the risk of hypertension. Postexercise hypotension (PEH) is an important tool in the prevention and management of hypertension; however, menopause may alter this response. The aim of this systematic review and meta-analysis [International Prospective Registered of Systematic Review (PROSPERO): CRD42023297557] was to evaluate the effect of exercise modalities (aerobic, AE; resistance, RE; and combined exercise, CE: AE + RE) on PEH in women, according to their menopausal status (premenopausal or postmenopausal). We searched controlled trials in PubMed, Web of Science, EBSCO, and Science Direct published between 1990 and March 2023. Inclusion criteria were normotensive, pre- and hypertensive, pre- and postmenopausal women who performed an exercise session compared with a control session and reported systolic blood pressure (SBP) and diastolic blood pressure (DBP) for at least 30 min after the sessions. Methodological quality was assessed using the PEDro scale. Standardized mean differences (Hedge's g) and their 95% confidence intervals (CIs) were calculated, and Q-test and Z-test were conducted to assess differences between moderators. Forty-one trials with 718 women (474 menopausal) were included. Overall, we found with moderate evidence that SBP and DBP decreased significantly after exercise session (SBP: g = -0.69, 95% CI -0.87 to -0.51; DBP: g = -0.31, 95% CI -0.47 to -0.14), with no difference between premenopausal and postmenopausal women. Regarding exercise modalities, RE is more effective than AE and CE in lowering blood pressure (BP) in women regardless of menopausal status. In conclusion, women's menopausal status does not influence the magnitude of PEH, and the best modality to reduce BP in women seems to be RE.NEW & NOTEWORTHY This meta-analysis has demonstrated that a single bout of exercise induces postexercise hypotension (PEH) in women and that the hormonal shift occurring with menopause does not influence the magnitude of PEH. However, we have shown with moderate evidence that the effectiveness of exercise modalities differs between pre- and postmenopausal women. Resistance and combined exercises are the best modalities to induce PEH in premenopausal women, whereas resistance and aerobic exercises are more effective in postmenopausal women.

Effect of Physical Exercise on Cardiac Autonomic Modulation in Hypertensive Individuals: A Systematic Review and Meta-analysis

BACKGROUND

Cardiac autonomic dysfunction is associated with hypertension and exercise training (ET) in healthy individuals is found to improve cardiac autonomic modulation (CAM). However, the effects of physical exercise on CAM in hypertensive individuals are under debate.

OBJECTIVE

The aim of the review is to systematically evaluate the literature on the effects of physical exercise on CAM in hypertensive individuals and analyse comparative differences in the effects of exercise between hypertensive and normotensive individuals.

METHODS

Electronic databases, such as Pubmed, PEDro, Scopus, and Web of Science, were systematically searched from inception up to February, 2022, evaluating the effect of ET on CAM either by heart rate variability (HRV), baroreflex sensitivity or heart rate recovery. Fifteen studies were included in the review. The risk of bias was assessed using the Cochrane risk of bias tool version 2 and the risk of bias in studies of intervention (ROBINS-I) tool. The overall quality of evidence was assessed using the grading of recommendations, assessment, development, and evaluation approach. Ten studies were included in the quantitative analysis. The meta-analysis and sensitivity analysis were performed using review manager 5.4.1; publication bias was assessed using Jamovi 2.2.5 software.

RESULTS

The qualitative analysis revealed low to moderate certainty of evidence for ET and moderate for aerobic training. For the effect of overall ET, the analysis revealed that the standardized mean differences (SMD) showed a significant effect of ET on HF (SMD 1.76, p = 0.04) and RMSSD (SMD 1.19, p < 0.0001) and a significant decrease in LF (SMD -1.78, p = 0.04). Aerobic training revealed nonsignificant improvement in HRV parameters. In the comparative analysis, ET did not show a significant difference in improvement between hypertensive and normotensive individuals.

CONCLUSION

This review suggests an improvement in CAM with physical exercise in hypertensive individuals, but the overall effect of ET in hypertensive individuals must be interpreted with caution as the robustness of the data is compromised in the sensitivity analysis of the trials. High-quality future trials focusing on different modes of ET interventions are needed to strengthen the findings of the present review.

Minimal Dose of Resistance Exercise Required to Induce Immediate Hypotension Effect in Older Adults with Hypertension: Randomized Cross-Over Controlled Trial

To determine the optimal exercise volume to generate a hypotension response after the execution of a single strength exercise in elderly subjects with hypertension (HT), a randomized crossover design was performed. A total of 19 elderly subjects with HT performed one control session and three experimental sessions of resistance training with different volumes in a randomized order: three, six, and nine sets of 20 repetitions maximum (RM) of a single elbow flexion exercise with elastic bands. The systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean heart rate (MHR) were tested at the beginning and immediately afterwards, at 30 and 60 min, and at 4, 5, and 6 h after the resistance exercise. The results show that the volumes of six and nine sets of 20 RM obtained statistically significant differences in the SBP at 30 and 60 min post-exercise (p < 0.05); in the DBP at 30 min after exercise (p < 0.05); and in the MHR immediately after exercise at 30 and 60 min (p < 0.05), compared to a control session. A single resistance exercise with a minimum volume of six sets of 20 RM generated an acute post-exercise antihypertensive response that was maintained for 60 min in elderly people with controlled HT.

Effects of exercise modalities on decreased blood pressure in patients with hypertension

This study aimed to evaluate the acute effects of aerobic and resistance exercises on blood pressure and endothelial blood markers. We also correlated post-exercise blood pressure response with baseline cardiovascular parameters in middle-aged patients with hypertension. This cross-sectional study randomized 54 volunteers into the aerobic exercise group (AG, n = 27; 45.6 ± 7.7 years) or dynamic resistance exercise group (RG, n = 27; 45.8 ± 8.4 years). Blood marker evaluation, cardiopulmonary exercise tests, resting blood pressure monitoring, ambulatory blood pressure monitoring (ABPM), flow-mediated dilatation monitoring, and body composition evaluation were carried out. Exercise sessions were performed to evaluate post-exercise hypotension (PEH) and endothelial marker responses, in addition to post-exercise ABPM (ABPMex). This study is an arm of the study which was approved by the local ethics committee (No. 69373217.3.0000.5347) in accordance with the Helsinki Declaration and was registered at ClinicalTrials.gov (NCT03282942). The AG performed walking/running at 60% of the reserve heart rate, while the RG performed 10 exercises with two sets of 15-20 repetitions. The mean 24 h ABPM and ABPMex values showed no significant statistical differences. Systolic and diastolic blood pressure hypotension after aerobic and dynamic resistance were -10.59 ± 5.24/-6.15 ± 6.41 mmHg and -5.56 ± 7.61/-6.20 ± 8.25 mmHg, respectively. For an up-to-7 h assessment of resting pressure, there was a positive effect in the aerobic group. The concentrations of nitrites/nitrates (NOx) and endothelin-1 (ET-1) did not change during hypotension. Moreover, PEH and ABPMex were significantly correlated with baseline health variables. Thus, when middle-aged patients with hypertension perform aerobic or resistance exercise, the NOx/ET-1 pathway does not provide the best explanation for PEH. Finally, we found associations between baseline cardiovascular variables and endothelial vasoconstrictors with PEH.

Acute Effects of Wearing Different Surgical Face Masks during High-Intensity, Short-Rest Resistance Exercise on Cardiorespiratory and Pulmonary Function and Perceptual Responses in Weightlifters

This study investigated the effect of wearing a typical surgical mask (SM) or a three-dimensional (3D) SM (3DSM) during whole-body, high-intensity, short-rest resistance exercise on cardiorespiratory, respiratory, and perceptual comfort responses in weightlifters. Twenty elite weightlifters (6 women and 14 men; age = 24.1 ± 4.9 years; height: 167.45 ± 7.60 cm; body mass = 76.48 ± 19.86 kg) who participated in this study performed 3 resistance exercise sessions in a randomized order: (1) without a mask (NM), (2) while wearing a typical SM, and (3) while wearing a 3DSM. Resistance exercise consisted of a descending pyramid scheme starting at 10 repetitions, with a decrease of one repetition per set for the back squat, bench press, and deadlift, as fast as possible at 75% of the one-repetition maximum. Cardiorespiratory and pulmonary function and comfort were measured. Across all conditions, effective postexercise hypotension (PEH) was noted in terms of decreased systolic blood pressure (−4.64%), diastolic BP (−5.36%), mean arterial pressure (−5.02%), and ankle–brachial index (−6.84%). However, the heart rate (40.34%) and rate of pressure product (33.60%) increased, and no effects on pulmonary function were observed in the three conditions. The participants reported higher breathing resistance and tightness when wearing a typical SM than when wearing a 3DSM or no mask. Therefore, both wearing and not wearing a face mask during whole-body, high-intensity, short-rest resistance exercise promoted PEH and exerted no detrimental effect on pulmonary function. Coaches, trainers, and athletes should consider wearing a 3DSM during resistance exercise.

Post-dynamic Resistance Exercise Hypotension: Exploring Individual Responses and Predictors

Background: Post-dynamic resistance exercise hypotension (PREH) has been largely demonstrated. However, little is known regarding the interindividual variation of PREH magnitude and its predictors (i.e. factors of influence).

Aims: To assess the interindividual variation of PREH and its predictors related to the characteristics of the individuals and the exercise protocol.

Methods: This study retrospectively analysed data from 131 subjects included in seven controlled trials about PREH (including at least one dynamic resistance exercise and one control session) conducted by two research laboratories. The interindividual variation was assessed by the standard deviation of the individual responses (SDIR), and linear regression analyses were conducted to explore the predictors.

Results: PREH showed moderate interindividual variation for systolic (SBP, SDIR=4.4mmHg; 0.35 standardised units) and diastolic blood pressures (DBP, SDIR=3.6mmHg; 0.32 standardised units). For systolic PREH, multivariate regression analysis (R2=0.069) revealed higher baseline SBP (B=−0.157, p=0.008) and higher number of sets (B=−3.910, p=0.041) as significant predictors. For diastolic PREH, multivariate regression analysis (R2=0.174) revealed higher baseline DBP (B=−0.191, p=0.001) and higher exercise volume (i.e. number of exercises *sets per exercise *repetitions per sets &gt;150; B=−4.212, p=0.001) as significant predictors.

Conclusion: PREH has a considerable interindividual variation. Greater PREH magnitude is observed in individuals with higher baseline blood pressure and after exercise protocols that comprehend higher number of sets and exercise volume.

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.

Cardiac autonomic and blood pressure responses to an acute session of battling ropes exercise

BACKGROUND

Battling rope (BTR) exercise has become incredibly popular among not only fitness enthusiasts and athletes but in the general exercising population. Despite its popularity, research regarding the acute cardiovascular responses to BTR exercise is limited. This investigation evaluated the effects of acute BTR exercise on heart rate variability (HRV) and blood pressure (BP) responses in young men with elevated BP.

MATERIALS AND METHODS

Eleven young men with elevated BP completed either a BTR or a non-exercise control trial in randomized order. The BTR trial consisted of 10 rounds of BTR exercise. Each round included 30 s of exercise followed by 30 s of rest. HRV and BP were evaluated at baseline and 3, 10, and 30 min following each trial.

RESULTS

There were significant elevations (p ˂0.01) in heart rate, markers of sympathetic activity (nLF), and sympathovagal balance (LnLF/LnHF, nLF/nHF) for 30 min following the BTR trial, whereas no changes from baseline were detected after control. Additionally, there were significant reductions (p ˂0.01) in markers of vagal tone (RMSSD, LnHF and nHF) and LnLF (both sympathetic and vagal modulations) for 30 min; as well as (p ˂0.01) systolic BP and diastolic BP at 10 and 30 min after the BTR, but not the control trial.

CONCLUSION

Current findings revealed that BTR exercise elevates sympathovagal balance for 30 min post-intervention, which is concurrent with an impressive hypotensive effect. Further investigations are warranted to assess the potential clinical application of BTR exercise not only in cohorts needing BP control but also in populations with limited locomotion that might benefit from post-exercise hypotension.

Combined Aerobic and Resistance Exercises Evokes Longer Reductions on Ambulatory Blood Pressure in Resistant Hypertension: A Randomized Crossover Trial

Aim

The present study compared the acute effects of aerobic (AER), resistance (RES), and combined (COM) exercises on blood pressure (BP) levels in people with resistant hypertension (RH) and nonresistant hypertension (NON-RH).

Methods

Twenty patients (10 RH and 10 NON-RH) were recruited and randomly performed three exercise sessions and a control session. Ambulatory BP was monitored over 24 hours after each experimental session.

Results

Significant reductions on ambulatory BP were found in people with RH after AER, RES, and COM sessions. Notably, ambulatory BP was reduced during awake-time and night-time periods after COM. On the other hand, the effects of AER were more prominent during awake periods, while RES caused greater reductions during the night-time period. In NON-RH, only RES acutely reduced systolic BP, while diastolic BP was reduced after all exercise sessions. However, the longest postexercise ambulatory hypotension was observed after AER (~11 h) in comparison to RES (~8 h) and COM (~4 h) exercises.

Conclusion

Findings of the present study indicate that AER, RES, and COM exercises elicit systolic and diastolic postexercise ambulatory hypotension in RH patients. Notably, longer hypotension periods were observed after COM exercise. In addition, NON-RH and RH people showed different changes on BP after exercise sessions, suggesting that postexercise hypotension is influenced by the pathophysiological bases of hypertension.

Cardiac baroreflex function and vascular reactivity recovery after aerobic exercise in patients with early cirrhosis

OBJECTIVE

To investigate the effects of aerobic exercise on the cardiac baroreflex function and vascular reactivity in patients with cirrhosis.

METHODS

Thirteen patients with cirrhosis were submitted to exercise and control intervention. At baseline and at 30 and 60 min following intervention, we evaluated cardiac baroreflex sensitivity (cBRS) and the baroreflex effectiveness index (BEI) using sequence technique. Vascular reactivity was assessed inducing reactive hyperemia before and 60 min after intervention.

RESULTS

At baseline, there was no difference (P interaction = 0.848) between exercise (from 3.0 ± 0.34 to 14.60 ± 1.06 ml/100ml/min) and control sessions (from 2.38 ± 0.10 to 13.73 ± 1.05 ml/100ml/min) regarding the increase in forearm blood flow during reactive hyperemia. However, this response was higher postexercise (from 3.38 ± 0.31 to 16.58 ± 1.58 ml/100ml/min) than postcontrol intervention (from 2.04 ± 0.23 to 11.98 ± 1.16 ml/100ml/min, P interaction < 0.001). BEI increased at 30- and 60-min postexercise (from 32 ± 7 to 42 ± 7 and 46 ± 7%), but not after control intervention (from 33 ± 6 to 31 ± 5 and 33 ± 7%, P interaction = 0.014). In contrast, cBRS decreased at 30-min postexercise (from 10.3 ± 1.9 to 8.2 ± 1.4 and 10.3 ± 2.1 ms/mmHg) and increased postcontrol intervention (from 7.9 ± 0.9 to 10.5 ± 1.5 and 10.3 ± 1.3 ms/mmHg, P interaction = 0.012).

CONCLUSION

The results suggest that a single bout of aerobic exercise improved cardiac baroreflex function and increased vascular reactivity in patients with early-stage cirrhosis.

Resistance Exercise Order Does Not Affect the Magnitude and Duration of Postexercise Blood Pressure in Older Women

Tomeleri, CM, Nunes, JP, Souza, MF, Gerage, AM, Marcori, A, Iarosz, KC, Cardoso-Júnior, CG, and Cyrino, ES. Resistance exercise order does not affect the magnitude and duration of postexercise blood pressure in older women. J Strength Cond Res 34(4): 1062-1070, 2020-The aim of this study was to compare the effects of 2 resistance exercise order on postexercise blood pressure (BP) in trained nonhypertensive older women. Sixteen women (68.3 ± 3.3 years, 63.5 ± 11.6 kg, 157.5 ± 5.1 cm) performed 2 sessions with 8 exercises (3 sets of 8-12 repetitions) in distinct orders (from multi- to single-joint exercises [MS] or from single- to multijoint exercises [SM]) and a control session (CS), without exercise. Blood pressure and heart rate (HR) were obtained pre- and postsessions (60 minutes). Postexercise hypotension was observed for systolic BP (SBP) and mean BP in both the MS session (SBP: -6.9 mm Hg, mean BP: -3.3 mm Hg, p ≤ 0.05) and SM session (SBP: -4.6 mm Hg; mean BP: -1.1 mm Hg). Postexercise HR was higher than presession values until 30 minutes of recovery in both training sessions. Furthermore, SBP and mean BP, and HR were lower than the values obtained in the CS (30-60 minutes and 0 minutes, respectively; p ≤ 0.05). There were no differences between the SM and MS sessions in any variable or at any moment. In conclusion, resistance exercise order does not interfere in the magnitude and duration of postexercise hypotension in trained nonhypertensive older women.

Dietary Determinants of Metabolic Syndrome Parameters Differ by Gender in College Students

MyPlate is a guidance system for healthier eating choices. In this cross-sectional study, we investigated the influence of MyPlate food group consumption and exercise on metabolic syndrome (MetS) parameters in college students. Participant (n = 462) blood was analyzed using Cholestech for triglycerides (TG), glucose, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). In addition, weight, waist circumference (WC), and blood pressure (BP) were measured. Diet and Wellness Plus was used to compute participant diet records. Regression analysis and a recursive decision tree were made to predict MetS using RStudio (V.1.1.463). BP decision tree predicted high risk of elevated blood pressure with a recall rate of 93.7%. For males; exercise, empty calories, dairy, and protein were main predictors. For females, vegetable and empty calorie consumption were primary determinants. HDL-C decision tree had a recall rate of 91.8% and showed that the main low HDL-C risk determinants for males were; exercise and grain consumption. Conversely, for females; empty calories, grain, and vegetable consumption were the key factors determining low HDL-C risk. This study shows that MyPlate recommendations are valuable to achieve adequate HDL-C and blood pressure and provides insight into the importance of tailoring food intake guidance based on gender.

High-intensity aerobic training lowers blood pressure and modulates the renal renin-angiotensin system in spontaneously hypertensive rats

Background: This study aimed to verify the effects of high-intensity aerobic training (HIAT) on BP control and renin-angiotensin system (RAS) components in renal tissue of SHR. Ten SHRs received HIAT or control for 8-weeks. At the end of the training, the SBP showed a reduction of ~ 30mmHg (p < .01) in HIAT and increased by ~ 15 mmHg in the  control group. HIAT resulted in a higher release of nitrite, IL-6, ACE2 and ATR2. These results indicated an association between BP, NO and renal RAS.Abbreviations: JAA: writing, carried out all experimental procedures, performed statistical analysis, original draft and revised manuscript DMS: data interpretation, formal analysis, writing, editing and revised manuscript BAP: carried all experimental procedures, revised manuscritpt CPCG: carried all experimental procedures, revised manuscritpt MEN: experimental procedures, revised manuscript and data interpretation RWP: drafted and revised manuscript RCA: writing, experimental procedures, revised manuscript JP: writing, data interpretation and revised manuscript OLF: writing, original draft and revised manuscript.

Exaggerated post exercise hypotension following concentric but not eccentric resistance exercise: Implications for metabolism

Post exercise hypotension (PEH) is primarily attributed to post-exercise vasodilation via central and peripheral mechanisms. However, the specific contribution of metabolic cost during exercise, independent of force production, is less clear. This study aimed to use isolated concentric and eccentric exercise to examine the role of metabolic activity in eliciting PEH, independent of total work. Twelve participants (6 male) completed upper and lower body concentric (CONC), eccentric (ECC), and traditional (TRAD) exercise sessions matched for work (3 × 10 in TRAD and 3 × 20 in CONC and ECC; all at 65% 1RM). Blood pressure was collected at baseline and every 15 min after exercise for 120 min. Brachial blood flow and vascular conductance were also assessed at baseline, immediately after exercise, and every 30 min after exercise. ⩒O₂ was lower during ECC compared to CONC and TRAD (-2.7 mL/Kg/min ± 0.4 and -2.2 mL/Kg/min ± 0.4, respectively p < 0.001). CONC augmented the PEH response (Peak ΔMAP -3.3 mmHg ± 0.9 [mean ± SE], p = 0.006) through 75 min of recovery and ECC elicited a post-exercise hypertensive response through 120 min of recovery (Peak ΔMAP +4.5 mmHg ± 0.8, p < 0.001). CONC and TRAD elicited greater increases in brachial blood flow post exercise than ECC (Peak Δ brachial flow +190.4 mL/min ± 32.3, +202.3 mL/min ± 39.2, and 69.6 mL/min ± 19.8, respectively, p ≤ 0.005), while conductance increased immediately post exercise in all conditions and then decreased throughout recovery following ECC (-32.9 mL/min/mmHg ± 9.3, p = 0.005). These data suggest that more metabolically demanding concentric exercise augments PEH compared to work-matched eccentric exercise.

Pathophysiology of Noncardiac Syncope in Athletes

The most frequent cause of syncope in young athletes is noncardiac etiology. The mechanism of noncardiac syncope (NCS) in young athletes is neurally-mediated (reflex). NCS in athletes usually occurs either as orthostasis-induced, due to a gravity-mediated reduced venous return to the heart, or in the context of exercise. Exercise-related NCS typically occurs after the cessation of an exercise bout, while syncope occurring during exercise is highly indicative of the existence of a cardiac disorder. Postexercise NCS appears to result from hypotension due to impaired postexercise vasoconstriction, as well as from hypocapnia. The mechanisms of postexercise hypotension can be divided into obligatory (which are always present and include sympathoinhibition, histaminergic vasodilation, and downregulation of cardiovagal baroreflex) and situational (which include dehydration, hyperthermia and gravitational stress). Regarding postexercise hypocapnia, both hyperventilation during recovery from exercise and orthostasis-induced hypocapnia when recovery occurs in an upright posture can produce postexercise cerebral vasoconstriction. Athletes have been shown to exhibit differential orthostatic responses compared with nonathletes, involving augmented stroke volume and increased peripheral vasodilation in the former, with possibly lower propensity to orthostatic intolerance.

Hemodynamic, Autonomic, Ventilatory, and Metabolic Alterations After Resistance Training in Patients With Coronary Artery Disease: A Randomized Controlled Trial

OBJECTIVE

The aim of this work was to evaluate the hemodynamic, autonomic, and metabolic responses during resistance and dynamic exercise before and after an 8-week resistance training program using a low-intensity (30% of 1 repetitium maximum), high-repetition (3 sets of 20 repetitions) model, added to an aerobic training program, in a coronary artery disease cohort.

DESIGN

Twenty male subjects with coronary artery disease (61.1 ± 4.7 years) were randomly assigned to a combined training group (resistance + aerobic) or aerobic training group (AG). Heart rate, stroke volume, cardiac output, minute ventilation, blood lactate, and parasympathetic modulation indices of heart rate (square root of the mean squared differences of successive RR intervals [RMSSD] and dispersion of points perpendicular to the line of identity that provides information about the instantaneous beat-to-beat variability [SD1]) were obtained before and after an 8-week RT program while performing exercise on a cycle ergometer and a 45-degree leg press.

RESULTS

Resistance training resulted in an increase in maximal and submaximal load tolerance (P < 0.01), a decreased hemodynamic response (P < 0.01), and a reduction in blood lactate in the combined training group compared to the aerobic training group during the 45-degree leg press. During exercise on a cycle ergometer, there was a decreased hemodynamic response and increased minute ventilation (P < 0.01). The 8-week RT program resulted in greater parasympathetic tone (RMSSD and SD1) and an increase in the SDNN index during exercise on a cycle ergometer and 45-degree leg press (P < 0.05).

CONCLUSIONS

An 8-week resistance training program associated with aerobic training may attenuate hemodynamic stress, and modify metabolic and autonomic responses during resistance exercise. The training program also appeared to elicit beneficial cardiovascular and autonomic effects during exercise.

Exercise, the Brain, and Hypertension

Exercise training is the cornerstone in the prevention and management of hypertension and atherosclerotic cardiovascular disease. However, blood pressure (BP) response to exercise is exaggerated in hypertension often to the range that raises the safety concern, which may prohibit patients from regular exercise. This augmented pressor response is shown to be related to excessive sympathetic stimulation caused by overactive muscle reflex. Exaggerated sympathetic-mediated vasoconstriction further contributes to the rise in BP during exercise in hypertension. Exercise training has been shown to reduce both exercise pressor reflex and attenuate the abnormal vasoconstriction. Hypertension also contributes to cognitive impairment, and exercise training has been shown to improve cognitive function through both BP-dependent and BP-independent pathways. Additional studies are still needed to determine if newer modes of exercise training such as high-intensity interval training may offer advantages over traditional continuous moderate training in improving BP and brain health in hypertensive patients.