Acute effects of different resistance training loads on cardiac autonomic modulation in hypertensive postmenopausal women

Abstract

BackgroundIndividuals with arterial hypertension often have an autonomic nervous system (ANS) imbalance with predominance of sympathetic ANS. This predominance can lead to injury of several organs affecting its functioning. There is evidence that performing high intensity resistance training (RT) with heavier loads and a lower number of repetitions results in lower cardiovascular stress when compared with lighter loads and a higher number of repetitions. However, the effects of different protocols of RT in autonomic modulation are not known. Therefore, the aim of the study was to analyze and compare the effects of different protocols of high intensity of effort RT on autonomic cardiac modulation of hypertensive women.MethodsA randomized crossover design clinical trial was conducted with 15 postmenopausal hypertensive women who underwent a control session and two high intensity RT protocols involving 6 and 15 repetition maximum (RM). Heart rate variability (HRV), systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) and double product (DP) were collected pre, immediately post, 1 h post, and 24 h post each protocol. Repeated-measures ANOVA were used.ResultsSBP was higher for 6RM than control immediately after session (p < 0.05). There were no differences for DBP among protocols (p ≥ 0.05). HR was higher for 15RM than 6RM and control immediately after and 1 h after session (p ≤ 0.05). DP values for 15RM were significantly higher than 6RM and control immediately after the session and remained higher than control 1 h after session (p ≤ 0.05). The indices that compose HRV (rMSSD) were lower after 15RM than 6RM and control (p ≥ 0.05). The parameters of parasympathetic activity (HF) were decreased and sympathetic (LF) activity was increased for 15RM when compared to the 6RM and control session immediately after the exercise session (p ≤ 0.05).ConclusionPerforming high intensity RT with lower loads and a higher number of repetitions seems to promote acute increases in sympathetic ANS activity, which may be related to cardiovascular stress. On the other hand, heavier load and lower repetition RT did not significantly impact upon autonomic modulation when compared to a control session.

Practical Recommendations Relevant to the Use of Resistance Training for COVID-19 Survivors

“…Therefore, it might be interesting to avoid such responses in COVID-19 survivors under rehabilitation. According to previous studies, RT protocols with a few number of repetitions (≤6 repetitions) and long between-sets rest intervals (≥3 min) result in less pronounced increases in sympathetic activity, cortisol, and lactate levels ( Kraemer et al, 1990 ; Smilios et al, 2003 , 2007 ; Vale et al, 2018 ). Moreover, low-volume RT with few repetitions is less glycolytic ( Knuiman et al, 2015 ).…”

Novel Resistance Training Approach to Monitoring the Volume in Older Adults: The Role of Movement Velocity

“…Nevertheless, several studies already observed that higher volumes do not provide additional strength gains than lower volumes in older adults [ 5 , 12 , 14 , 15 , 16 ]. It is also important to note that when older adults perform a high number of repetitions per set closely to concentric failure, there is a higher acute cardiovascular, metabolic, and neuromuscular stress than for a low volume, which might be harmful in this population [ 17 , 18 , 19 ]. Therefore, considering that no consensus exists regarding the optimal training volume in older adults, alternative approaches must be evaluated.…”

Use of low volume, high effort resistance training to manage blood pressure in hypertensive patients inside a public hospital: a proof of concept study

“…22,23 The choice of small number of repetitions (<10) was for safety reasons, since it promotes lower acute increases in blood pressure, HR, double product, [24][25][26] and promotes better autonomic modulation than performing a higher number of repetitions. 27 Resistance training sessions were composed of four multi-joint exercises, with two sets for each exercise, two minutes interval between sets and a speed of two seconds in both eccentric and concentric phase. Multi-joint exercises were selected due to the evidence that they are more efficient in improving general physical fitness, maximal oxygen uptake and muscular strength than single joint exercises, 18 and there is also evidence that the addition of single joints exercises to a multi-joint exercise program does not lead to morphological or functional benefits.…”