Postexercise hypotension and autonomic modulation response after full versus split body resistance exercise in trained men

Comparison Between Traditional and Alternated Resistance Exercises on Blood Pressure, Acute Neuromuscular Responses, and Rating of Perceived Exertion in Recreationally Resistance-Trained Men

ABSTRACT

Corrêa Neto, VG, Silva, DdN, Palma, A, de Oliveira, F, Vingren, JL, Marchetti, PH, da Silva Novaes, J, and Monteiro, ER. Comparison between traditional and alternated resistance exercises on blood pressure, acute neuromuscular responses, and rating of perceived exertion in recreationally resistance-trained men. J Strength Cond Res 38(5): e211-e218, 2024-The purpose of this study was to compare the acute effects of traditional and alternated resistance exercises on acute neuromuscular responses (maximum repetition performance, fatigue index, and volume load), rating of perceived exertion (RPE), and blood pressure (BP) in resistance-trained men. Fifteen recreationally resistance-trained men (age: 26.40 ± 4.15 years; height: 173 ± 5 cm, and total body mass: 78.12 ± 13.06 kg) were recruited and performed all 3 experimental conditions in a randomized order: (a) control (CON), (b) traditional (TRT), and (c) alternated (ART). Both conditions (TRT and ART) consisted of 5 sets of bilateral bench press, articulated bench press, back squat, and Smith back squat exercises at 80% 1RM until concentric muscular failure. The total number of repetitions performed across sets in the bench press followed a similar pattern for TRT and ART, with significant reductions between sets 3, 4, and 5 compared with set 1 (p < 0.05). There was a significant difference for set 4 between conditions with a lower number of repetitions performed in the TRT. The volume load was significantly higher for ART when compared with TRT. TRT showed significant reductions in BP after 10-, 40-, and 60-minute postexercise and when compared with CON after 40- and 60-minute postexercise. However, the effect size illustrated large reductions in systolic BP during recovery in both methods. Thus, it is concluded that both methods reduced postexercise BP.

Central and peripheral mechanisms underlying postexercise hypotension: a scoping review

Blood pressure (BP) reduction occurs after a single bout of exercise, referred to as postexercise hypotension (PEH). The clinical importance of PEH has been advocated owing to its potential contribution to chronic BP lowering, and as a predictor of responders to exercise training as an antihypertensive therapy. However, the mechanisms underlying PEH have not been well defined. This study undertook a scoping review of research on PEH mechanisms, as disclosed in literature reviews. We searched the PubMed, Web of Science, Scopus, Cumulated Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, and Sport Discus databases until January 2023 to locate 21 reviews - 13 narrative, four systematic with 102 primary trials, and four meta-analyses with 75 primary trials involving 1566 participants. We classified PEH mechanisms according to major physiological systems, as central (autonomic nervous system, baroreflex, cardiac) or peripheral (vascular, hemodynamic, humoral, and renal). In general, PEH has been related to changes in autonomic control leading to reduced cardiac output and/or sustained vasodilation. However, the role of autonomic control in eliciting PEH has been challenged in favor of local vasodilator factors. The contribution of secondary physiological outcomes to changes in cardiac output and/or vascular resistance during PEH remains unclear, especially by exercise modality and population (normal vs. elevated BP, young vs. older adults). Further research adopting integrated approaches to investigate the potential mechanisms of PEH is warranted, particularly when the magnitude and duration of BP reductions are clinically relevant. (PROSPERO CRD42021256569).

Effects of remote ischemic conditioning on conditioned pain modulation and cardiac autonomic modulation in women with knee osteoarthritis: placebo-controlled randomized clinical trial protocol

BACKGROUND

It is estimated that over 240 million people worldwide have osteoarthritis, which is a major contributor to chronic pain and central changes in pain processing, including endogenous pain modulation. The autonomic nervous system plays a crucial role in the pain regulatory process. One of the main mechanisms of remote ischemic conditioning is neuronal signaling from the preconditioned extremity to the heart. This study aims to analyze the acute effect of remote ischemic conditioning on local pain, conditioned pain modulation, and cardiac autonomic control in women with knee osteoarthritis and to see if there is a correlation between them.

METHODS

Women more than 50 years with knee osteoarthritis diagnosed according to the American College of Rheumatology criteria in the postmenopausal period will be considered eligible. The study will have blind randomization, be placebo-controlled, and be balanced in a 1:1 ratio. The total of 44 participants will be divided into two groups (22 participants per group): (i) remote ischemic conditioning and (ii) placebo remote ischemic conditioning. Protocol consisting of four cycles of total ischemia, followed immediately by four cycles of 5 min of vascular reperfusion, totaling 40 min. The primary outcomes in the protocol are conditioned pain modulation, which has the pressure pain threshold (kgf/cm2) as its primary outcome measure, and cardiac autonomic modulation, which has the indices found in heart rate variability as its primary outcome measure. Comparisons will be performed using generalized linear mixed models fitted to the data. For correlation, the Pearson or Spearman test will be used depending on the normality of the data. All analyses will assume a significance level of p < 0.05.

DISCUSSION

It is believed that the results of this study will present a new perspective on the interaction between the pain processing system and the cardiovascular system; they will provide the professional and the patient with a greater guarantee of cardiovascular safety in the use of the intervention; it will provide knowledge about acute responses and this will allow future chronic intervention strategies that aim to be used in the clinical environment, inserted in the multimodal approach, for the treatment of osteoarthritis of the knee.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05059652. Registered on 30 August 2021. Last update on 28 March 2023.

Short-Term Effects of Land-Based Versus Water-Based Resistance Training Protocols on Post-Exercise Hypotension in Normotensive Men: A Crossover Study

Considering that water immersion may acutely reduce blood pressure (BP) and that exercise may elicit positive post-exercise hypotension (PEH) responses, we aimed to analyze the presence of PEH in normotensive individuals and compare its magnitude between two resistance training sessions performed in aquatic or land environments. Ten physically active men (23.2 ± 3.1 years) performed the two training protocols in a randomized, counterbalanced fashion. BP measurements were performed for 30 min (at 5 min intervals) both prior to (resting) and after each of the protocols. No differences were observed between protocols at baseline (p > 0.05). Only the water-based resistance training protocol resulted in a systolic BP reduction from 10 to 20 min post-exercise (all p < 0.05) compared to baseline. Compared to the land-based session, systolic BP was lower in the water-based protocol from 10 to 25 min post-exercise (all p < 0.05). On the other hand, diastolic BP showed a similar PEH effect between water and land-based protocols for the entire 30 min post-session period (all p < 0.001). Our results suggest that water-based resistance training holds the potential as a nonpharmacological strategy to lower BP levels following exercise.

Cardiac Autonomic Function Following Bilateral and Unilateral Upper Body Acute Resistance Exercise

The purpose of this study was to compare cardiac autonomic responses following bilateral and unilateral upper-body (UB) acute resistance exercise (ARE). In total, 14 individuals were assessed for markers of cardiac autonomic responses via heart rate variability (HRV) and baroreflex sensitivity (BRS) at rest and at 10- and 30-min following ARE. Logarithmically transformed (ln) HRV measures included: total power (ln TP), high-frequency power (ln HF power), low-frequency power (ln LF power), sympathovagal balance (ln LF: HF), and the square root of the mean squared differences of successive R-R intervals (ln RMSSD). BRS was assessed using the sequence method. Two-way repeated measures ANOVAs were used to analyze effects of UB ARE (bilateral, unilateral) across time (Rest, 10, and 30 min). There were no significant (p > 0.05) interactions. However, there were significant (p ≤ 0.05) main effects of time such that ln TP, ln HF power, ln RMSSD, and BRS decreased and did not recover within 30 min compared to Rest for both conditions. Collectively, this study suggests that bilateral and unilateral UB ARE yielded similar reductions, for at least 30 min, in respect to vagal measures of HRV and BRS.

Factors that affect heart rate variability following acute resistance exercise: A systematic review and meta-analysis

BACKGROUND

There is controversial evidence regarding the effect of acute resistance exercise (ARE) on heart rate variability (HRV) parameters, which indicates the activities of the cardiac autonomic nervous system. The aim of this study was to perform a systematic review and meta-analysis of the literature on the effect of ARE on HRV parameters and identify its possible moderating factors.

METHODS

The PubMed-Medline, Web of Science, SPORTDiscus, and Cochrane Library databases were searched. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) declaration was followed, and the methodological quality of the studies was evaluated. The level of significance was set at p ≤ 0.05. Twenty-six studies met the inclusion criteria. Main effect analyses between pre- and post-test interventions demonstrated an increase in normalized units low frequency (p < 0.001; standardized mean difference (SMD) = 0.78; 95% confidence interval (95%CI): 0.46‒1.11) and low frequency/high frequency ratio (p < 0.001; SMD = 0.82; 95%CI: 0.64‒0.99) and a decrease in standard deviation of the normal-to-normal (NN) interval (p < 0.001; SMD = -0.58; 95%CI: -0.85 to -0.30), root mean square of the successive differences (p < 0.001; SMD = -1.01; 95%CI: -1.29 to -0.74), and normalized units high frequency (p < 0.001; SMD: -1.08; 95%CI: -1.43 to -0.73) following ARE in healthy individuals range: 15 ± 1 to 48 ± 2 years; mean ± SD).

RESULTS

There were differences between the subgroups in the number of sets used in an exercise (p = 0.05) for root mean square of the successive differences, as well as for exercise intensity (p = 0.01) and rest between sets (p = 0.05) for normalized units high frequency. Interestingly, there were differences between the subgroups in training volume for root mean square of the successive differences (p = 0.01), normalized units high frequency (p = 0.003) and normalized units low frequency (p = 0.02).

CONCLUSION

Overall, there was a withdrawal of cardiac parasympathetic and activation of cardiac sympathetic modulations following ARE, and these changes were greater with higher training volume ∼30 min after ARE in healthy individuals. Furthermore, the number of sets, intensity, and rest between sets affected HRV parameters. However, gender, body mass index, and training status did not influence the changes in HRV parameters as a response to ARE.

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.

Sex-Specific Autonomic Responses to Acute Resistance Exercise

Background and Objectives: Acute resistance exercise (RE) reduces vagal modulation and increases sympathovagal balance, which increases the risk for arrythmias. Few studies have examined sex differences in autonomic modulation after acute RE. The purpose of this investigation was to examine sex-specific responses to acute RE on autonomic modulation. Materials and Methods: Twenty-one resistance-trained individuals (men n = 11, women n = 10) between the ages of 19 and 25 y were analyzed for autonomic modulation in response to acute RE and a control (CON). Measures of autonomic modulation were collected at rest, 15 (R15), and 30 (R30) min following both conditions. Heart rate (HR), log transformed root mean square of successive differences (lnRMSSD), total power (lnTP), low-frequency power (lnLF), high-frequency power (lnHF), sample entropy (SampEn), and Lempel-Ziv entropy (LZEn) were measured at all time points. A three-way repeated analysis of variance (ANOVA) was used to analyze sex (men, women) across condition (RE, CON) and time (Rest, R15, R30). Results: The results are similar for all heart rate variability (HRV) variables at rest for both conditions (RE, CON). SampEn was significantly higher in men compared to women at rest for both conditions (p = 0.03), with no differences in LZEn (p > 0.05). There were no significant (p > 0.05) three-way interactions on any variables. Condition by time interactions demonstrated that both sexes increase in HR (p = 0.0001) and lnLF/HF ratio (p = 0.001), but decreases in lnRMSSD (p = 0.0001), lnTP (p < 0.0001), lnLF (p < 0.0001), lnHF (p = 0.0001), and LZEn (p = 0.009) at R15 and R30 compared to rest following acute RE and were different from CON. Condition by time interaction (p = 0.017) demonstrated that SampEn was attenuated at R15 compared to rest, and the CON, but not R30 following acute RE. Conclusion: Although SampEn is more complex at rest in men compared to women, autonomic modulation responses between sexes following acute RE appear to be similar.

The Effects of Machine-Weight and Free-Weight Resistance Exercise on Hemodynamics and Vascular Function

The purpose of this study was to examine hemodynamic and vascular responses between machine-weight and free-weight exercise. Resistance-trained individuals were assigned to a machine-weight (n = 13) or free-weight (n = 15) group. Groups completed two visits consisting of their assigned exercise condition and a control (CON). A 2 × 2 × 3 repeated measures ANOVA was used to test the effects of group across condition and time on the hemodynamic parameters [cardiac output (CO), heart rate (HR), total peripheral resistance (TPR), mean arterial pressure (MAP), and stroke volume (SV)]. A 2 × 2 × 2 repeated measures ANOVA was used to test the effects of group across condition and time on the hemodynamic variable, forearm vascular conductance (FVC), as well as on vascular measures [forearm blood flow (FBF), blood flow peak, and total reactive hyperemia (RH)]. Main effects were analyzed using pairwise comparisons. The results of the present study demonstrate that both machine-weight and free-weight exercise produce similar (p > 0.05) alterations in hemodynamics and vascular function. Specifically, during recovery both groups demonstrated significant (p ≤ 0.05) increases in measures of hemodynamics such as CO, HR and FVC, as well as significant (p ≤ 0.05) decreases in TPR, MAP, and SV. Measures of vascular function such as FBF, blood flow peak, and total RH were also significantly (p ≤ 0.05) increased during recovery. Therefore, this study suggests that either machine weight or free-weight exercise may induce acute hemodynamic and vascular benefits, which may reduce the risk of cardiovascular disease (CVD) and CVD events.