ECSS Paris 2023: OP-MH39
INTRODUCTION: Blood pressure (BP) response during exercise (Ex) exhibits significant variability, even among young normotensive individuals. One of the key mechanisms regulating BP during Ex is the exercise pressor reflex, which includes the mechanoreflex and metaboreflex. These reflexes are activated by mechanical and chemical stimuli induced by skeletal muscle contraction, which is regulated by motor unit (MU) behavior, particularly MU firing rate (MUFR) modulation. Notably, MUFR decreases in the early phase of Ex and subsequently increases in the later phase, although this pattern varies among individuals. Furthermore, the early phase of the BP response during Ex is primarily associated with the mechanoreflex, while the later phase is influenced by both the mechano- and metabo-reflex. Therefore, individual differences in MUFR modulation may be linked to variations in mechanoreflex-induced BP response during the early phase of Ex, and in mechanoreflex- and/or metaboreflex-induced BP response during the later phase in young normotensive individuals. METHODS: Fifteen young males and seventeen females performed a 1-minute isometric knee extension Ex at 30% of their maximal voluntary contraction (MVC), followed by post-exercise muscle ischemia (PEMI). Beat-by-beat systolic BP (SBP) was continuously measured, and the slope of the linear regression between baseline and 30 seconds (early phase) and between 30 and 60 seconds (later phase) was analyzed for each individual. The change in mean arterial pressure (ΔMAP) from baseline to PEMI was calculated to assess individual differences in metaboreflex activity. High-density surface electromyography signals recorded during Ex were used to assess MUFR modulation. MUFR was analyzed via the slope of the linear regression between the start of Ex and 30 seconds (early phase) and between 30 and 60 seconds (later phase). RESULTS: Although previous studies have reported that absolute knee extension torque can affect the BP response during Ex, no significant relationships were observed between MVC and BP response or MUFR modulation during Ex in either males and females (P = 0.195 - 0.974). In males, variability in SBP response was significantly associated with MUFR in the early phase of Ex (P = 0.005, r = 0.682), but not in the later phase (P = 0.242). Variability in ΔMAP was not associated with MUFR in both Ex phase (P = 0.791 and P = 0.290, respectively). However, ΔMAP was significantly associated with SBP response in the later phase (P = 0.003, r = 0.712). In females, no significant relationships were found between MUFR and BP response. CONCLUSION: In males, individuals with a smaller decrease in MUFR exhibited a greater increase in the mechanoreflex-induced BP response during the early phase of Ex. In contrast, during the later phase, a greater increase in BP response was associated with higher metaboreflex activity rather than MUFR modulation. No significant relationships were observed in females.
Read CV Ryosuke TakedaECSS Paris 2023: OP-MH39
INTRODUCTION: This observational cohort study aimed to assess overall and sex-dependent variations in office blood pressure measurements (OBPM) in a cohort of patients affected by intermittent claudication (IC) and resistant hypertension (RH) enrolled in an in-home low intensity interval walking program. METHODS: From a cohort of 1205 patients with IC consecutively enrolled between 2011 and 2023, those with RH were included. All patients performed the in-home Test in-Train out pain-free walking program [1] composed of eight bouts of 1:1 interval walk:rest ratio at a prescribed speed, weekly increased from approximately 60 to 100% of habitual gait speed. The exercise program was updated during three intermediate visits and lasted for approximately 6 months. The OBPM were collected at baseline (T0), at circa-monthly visits (T1, T2, T3) and at the end of the program (T4) by the same medical doctor with the patient laying in supine position for at least 5 minutes. Variations in drug therapy were also collected. RESULTS: A total of 220 patients were affected by RH (aged 73±9 years; 170 males). All patients completed the exercise program (session completed 84±11%) without adverse events. Fourteen patients underwent changes in drug therapy during the follow up and were excluded. The remaining 206 patients presented a progressive decline of systolic blood pressure (SBP) (t = -7.11; p<0.001) from T0 to T4 with a mean decrease of -10±8 mmHg (from 159±17 to -149±17mmHg) and of diastolic pressure of -1±5 mmHg. The repeated-measure analysis of variance excluded a significant sex per time interaction for both SBP (p=0.28) and DBP (p=0.44). In particular, women exhibited a significant decrease (p<0.001) in SPB from 162±17 to 152±16 mmHg; p<0.001) comparable to men (from 156±16 to 146±17mmHg; p<0.001). CONCLUSION: In a population at high cardiovascular risk with claudication and RH, a low volume of structured low-intensity home-based exercise improved blood pressure control in both women and men, representing a favourable adjuvant to pharmacological therapy. References: Manfredini F, et al. Training rather than walking: the test in -train out program for home-based rehabilitation in peripheral arteriopathy. Circ J. 2008 Jun;72(6):946-52.
Read CV Lorenzo CarusoECSS Paris 2023: OP-MH39
INTRODUCTION: Isometric resistance training (IRT) is an alternative, time-efficient approach to hypertension management [1]. Yet established methods have restricted exercise variability and present participation barriers, including access to and cost of specialised non-portable equipment [2]. A novel cost-effective isometric training band (ITB) has safely demonstrated significant blood pressure (BP) reductions [3]. However, efficacy in pre- and hypertensive adults in unsupervised environments is yet to be established. Therefore, the present study compared the effects of an 8-week, home-based multi-exercise ITB intervention to volume matched isometric handgrip (IHG) on resting, and ambulatory blood pressure in pre- and hypertensive adults. METHODS: Using a parallel randomised control trial, thirty-eight pre-hypertensive (n = 17, sBP 135 ± 1 mmHg) and stage 1 hypertensive (n = 21, 147 ± 6 mmHg) adults were recruited into a control (CON, n = 13), IHG (n = 13) or ITB (n = 12) group. Resting systolic (sBP), diastolic (dBP), mean arterial pressure (mBP), heart rate (HR) and ambulatory BP (24-hour, daytime, night-time) were measured at baseline and following 4, and 8 weeks of unsupervised home-based IRT (4 x 2-min bouts, 3x week). Data were analysed using factorial ANOVAs (time [pre-, mid- and post-testing] x group [CON, ITB, and IHG]) to examine any significant within and between group differences, with post-hoc effect sizes calculated using Cohen’s d. RESULTS: After 4 weeks resting sBP significantly reduced in the IHG (10.2 ± 4.1 mmHg, d = -1.63) but not in the ITB group (1.8 ± 4.1 mmHg, d = -0.56). Following 8 weeks resting sBP significantly decreased for both training groups (ITB: 9.0 ± 3.2 mmHg, d = -1.36; IHG: 12.0 ± 3.1 mmHg, d = -1.48) compared to CON, although not significant between training groups (2.3 ± 3.2 mmHg, d = 0.32). Comparably, significant reductions in 24-hour (ITB: 7.6 ± 1.5 mmHg, d = 1.42; IHG: 6.9 ± 1.5 mmHg, d = 1.33), daytime (ITB: 7.3 ± 1.6 mmHg, d = 1.33; IHG: 6.3 ± 1.5 mmHg, d = 1.21), and night-time sBP (ITB: 8.5 ± 1.7 mmHg, d = 1.39; IHG: 8.8 ± 2.1 mmHg, d = 1.38) occurred for both training groups after 8 weeks. Whereas reductions in 24-hour (6.2 ± 1.4 mmHg, d = 1.2) and daytime mBP (6.7 ± 2.5 mmHg, d = 1.16) occurred in the ITB group only. No significant decreases in resting or ambulatory dBP or HR occurred for either group. CONCLUSION: The BP reductions in both training groups provide further evidence for the efficacy of IRT, however, results suggest the onset of effects may vary depending on modality. Importantly, the equivalent sBP reductions between training groups at 8 weeks highlight the potential of the ITB as a versatile, cost-effective, and accessible approach to IRT for BP management in pre- and hypertensive populations. References 1. Edwards et al. (2023). Br J Sports Med. 57(20): 1317–1326. 2. Cornelissen, V.A. (2023). Blood Pressure. 32(1): 2208232. 3. Wright et al. (2023). Eur. J. Public Health. 33(1): 133-168.
Read CV Ben WrightECSS Paris 2023: OP-MH39