Effects of Different Modes of Isometric Resistance Training on Ambulatory Blood Pressure Variability in Healthy Normotensives

Description

INTRODUCTION: One third of deaths globally each year are associated with hypertension, a modifiable risk factor for cardiovascular disease. Diurnal blood pressure (BP) variability including morning blood pressure surge (MBPS) and average real variability (ARV) of ambulatory BP, are associated with increased risk of stroke, heart failure and end-organ damage. Laboratory isometric resistance training (IRT) protocols have identified reductions in ambulatory BP MBPS and ARV following 8-10 weeks of training, however no research has investigated the effects of short-term IRT on ambulatory measures in normotensives. Therefore, the purpose of this study was to determine the effects of a novel home-based IRT device on ambulatory BP, MBPS and ARV in normotensives following 4 weeks of IRT.

METHODS: Thirty-eight normotensives (20 men, age = 33 ± 14 yr; 18 women, age = 28 ± 13 yr) were randomly assigned to an isometric handgrip training (IHG, n = 13), isometric training band (ITB, n = 12) or control (CON, n = 13) group. Before and after the 4-week laboratory-based training programme, resting and ambulatory BP, MBPS (mean systolic BP 2 hours after waking, minus the lowest sleeping 1-hour mean systolic BP) and ARV (calculated as previously reported [1]) were measured. IRT consisted of 4 x 2-minute contractions at 30% MVC (IHG) or at a perceived rate of exercise exertion equivalent to 30% MVC (IBT), with 2-minute rest periods, 3 days per week. A two-way repeated measures ANOVA was used to assess the within and between groups changes in resting, ambulatory BP MBPS and ARV.

RESULTS: Significant (P < 0.05) reductions were detected in resting systolic BP for both training modes (IHG = -5 ± 4mmHg; ITB = -5 ± 3mmHg) with no further reductions in resting BP measures. Additionally, no significant reductions were seen in 24-h (IHG = -1 ± 6mmHg; ITB = 2 ± 7mmHg), daytime (IHG = 0 ± 6mmHg; ITB = 1 ± 7mmHg) or night-time systolic ambulatory BP (IHG = -4 ± 7mmHg; ITB = -4 ± 8mmHg). Furthermore, no significant changes were observed in the MBPS (IHG = -1 ± 15mmHg; ITB = 1 ± 10mmHg), 24-h (IHG = 1 ± 3mmHg; ITB = 1 ± 2mmHg) or daytime (IHG = -1 ± 2mmHg; ITB = 0 ± 2mmHg) ambulatory ARV systolic BP.

DISCUSSION: These results support the unpublished data establishing the novel training device as a valid tool for lowering resting systolic BP and provides further evidence that IRT is effective for lowering resting BP in normotensives. However, the lack of significant reductions in ambulatory BP, MBPS and ARV following a four-week IRT programme may indicate that for diurnal BP reductions to occur a longer training stimulus may be needed. Further, the absence of any ambulatory reductions may be associated with the proposed biphasic pattern to vascular adaptations.

REFERENCES
1.Boardman et al. (2017). J Hyperten. 35(3);513–522.
2.Tinken et al. (2008). J Physiol. 586;5003–5012.

Period	7 Jul 2023
Event title	28th Annual Congress of the European College of Sport Science (ECSS)
Event type	Conference
Location	Paris, FranceShow on map
Degree of Recognition	International