Hemodynamics and cardiac autonomic modulation after an acute concurrent exercise circuit in older individuals with pre- to established hypertension

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).

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.

Central Hemodynamic Adjustments during Post-Exercise Hypotension in Hypertensive Patients with Ischemic Heart Disease: Concurrent Circuit Exercise versus High-Intensity Interval Exercise. A Preliminary Study

Concurrent aerobic plus resistance exercise (RAE) and high-intensity interval exercise (HIIE) are both effective at inducing post-exercise hypotension (PEH) in patients with hypertension. However, central hemodynamic changes associated with PEH in hypertensive subjects with underlying ischemic heart disease (IHD) have been poorly investigated. The study aim was to compare the acute effects produced by these two exercise modalities on left ventricular diastolic function and left atrial function. Twenty untrained male patients with a history of hypertension and IHD under stable pharmacological therapy were enrolled. Each patient underwent three exercise sessions: RAE, HIIE and a control session without exercise, each lasting 45 min. An echocardiography examination was performed before and between 30 min and 40 min from the end of the exercise sessions. Following the exercise sessions, BP values decreased in a similar way in RAE and HIIE and were unchanged after the control session. Compared to pre-session, the ratio between early filling velocity (E) and mitral annulus early diastolic velocity (E’). E/E’ increased after HIIE and remained unchanged after both RAE and control sessions (between-sessions p 0.002). Peak atrial longitudinal strain (PALS) increased slightly after RAE (+1.4 ± 1.1%), decreased after HIIE (−4.6 ± 2.4%) and was unchanged after the control session (between-sessions p 0.03). Peak atrial contraction strain (PACS) was mildly increased after RAE, was reduced after HIIE and was unchanged after the control session. Atrial volume was unchanged after both exercise sessions. Left ventricular and left atrial stiffness increased significantly after HIIE, but remained unchanged after the RAE and control sessions. Stroke volume and cardiac output increased after RAE, decreased after HIIE, and were unchanged after the control session. In conclusion, single session of RAE and HIIE brought about similar PEH in hypertensive subjects with IHD, while they evoked different central hemodynamic adjustments. Given its neutral effects on diastolic and atrial functions, RAE seems more suitable for reducing blood pressure in hypertensive patients with IHD.