Effects of Isometric Resistance Training and Detraining on Ambulatory Blood Pressure and Morning Blood Pressure Surge in Young Normotensives

Anthony Baross, Cheri McGowan, Gina Jay, Lydia Stoodley, Ian L Swaine

Research output: Contribution to ConferenceAbstractpeer-review

Abstract

Introduction
Hypertension is a modifiable risk factor for cardiovascular disease (CVD) and is a leading cause of morbidity and premature mortality globally. Diurnal blood pressure (BP) variability, particularly the morning blood pressure surge (MBPS) is associated with increased end-organ damage and increased risk of stroke, and is a destabilising factor for atherosclerotic plaque. Isometric resistance training (IRT) has been shown to reduce ambulatory BP following 4-12 weeks of training and there is preliminary data to suggest that it can reduce the MBPS. However, there is no data available regarding how long, after cessation of IRT, the effects on ambulatory BP and the MBPS are maintained during detraining. Therefore, the purpose of this study was to determine the effects of IRT on ambulatory BP and the MBPS in young normotensives following (i) 8 weeks of IRT and (ii) 8 weeks of detraining.

Methods
Twenty-five normotensive individuals (16 men, age=23±6 years; 9 women, age=22±4 years) were randomly assigned to a training-detraining (TRA-DT, n=13) or control (CON, n=12) group. Ambulatory BP and MBPS were measured prior to, and after 8 weeks of bilateral leg IRT using an isokinetic dynamometer (4 x 2-minute contractions at 20% MVC with 2-minute rest periods, 3 days/week). These measurements were then repeated, following an 8-week detraining period. A two-way repeated measures MANOVA was used to assess the within and between groups changes in ambulatory BP and MBPS. MBPS was calculated as: mean systolic BP 2 hours after waking, minus the lowest sleeping 1-hour mean systolic BP.

Results
There were significant reductions in 24-h ambulatory systolic BP following IRT (pre-to-post training, -8±4 mmHg, p=0.00) and these reductions were maintained after detraining (pre-to-post detraining, -6±5 mmHg, p=0.008). There were significant reductions in daytime BP (pre-to-post training, -5±4 mmHg, p=0.001) which were maintained after detraining (pre-to-post detraining, -4±5 mmHg, p=0.022), but there was no change in night-time systolic BP (pre-to-post training, -2±4 mmHg, p=0.25) and this was also the case after detraining (pre-to-post detraining, 1±6 mmHg, p=1.0). Additionally, there were significant reductions in the MBPS (pre-to-post training, -6±9 mmHg, p=0.000) which were maintained after detraining (pre-to-post detraining, -5±9 mmHg, p=0.02).

Discussion
These results confirm that IRT causes significant reductions in ambulatory BP. Furthermore, there are significant reductions in the MBPS, which could offer the potential for clinically meaningful CVD and stroke risk reduction. Importantly, ambulatory systolic BP and the MBPS changes remained significantly lower than baseline for 8-weeks after cessation of training, suggesting that the effects of IRT on these measures are prolonged.
Original languageEnglish
Pages1
Publication statusPublished - 6 Jul 2019
Event24th Annual Congress of the European College of Sport Science (ECSS) - Prague, Czech Republic
Duration: 3 Jul 20196 Jul 2019
http://ecss-congress.eu/2019/19/index.php

Conference

Conference24th Annual Congress of the European College of Sport Science (ECSS)
Country/TerritoryCzech Republic
CityPrague
Period3/07/196/07/19
Internet address

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