No Decrease in Blood Pressure After an Acute Bout of Intermittent Hyperpnea and Hypoxia in Prehypertensive Elderly

Abstract

Prevalence of hypertension, subjective sleep complaints and snoring increases with age. Worse sleep and snoring, in turn, are independent risk factors to develop hypertension. Both respiratory muscle training (RMT) and intermittent hypoxia (IH) are suggested to have positive effects on these physiological and behavioral variables. This study therefore aimed to test the acute effects of a single bout of RMT, with and without IH, on resting blood pressure (BP) and sleep. Fourteen prehypertensive elderly performed a 60-min session of (a) intermittent voluntary normocapnic hyperpnea (HYP) alone, (b) HYP in combination with IH (HYP&IH) and (c) a sham intervention in randomized order. BP, hemodynamics, heart rate variability (HRV), cardiac baroreflex sensitivity (BRS) and pulse wave velocity (PWV) were assessed before and 15, 30 and 45 min after each intervention. Variables of sleep were assessed with actigraphy, pulse oximetry and with questionnaires during and after the night following each intervention. Neither HYP nor HYP&IH resulted in a decrease in BP. Repeated measures ANOVA revealed no significant interaction effect for systolic BP ( p = 0.090), diastolic BP ( p = 0.151), HRV parameters, BRS and PWV (all p > 0.095). Fragmentation index was lower after both HYP (−6.5 units) and HYP&IH (−8.4 units) compared to sham, p (ANOVA) = 0.046, although pairwise comparisons reveal no significant differences. There were no other significant effects for the remaining sleep variables. We conclude that one bout of intermittent hyperpnea, alone or in combination with IH, is not effective in lowering blood pressure or improving sleep in prehypertensive elderly.

Hypoxia and the Aging Cardiovascular System

“…Responses may largely differ after one session of intermittent hypoxic exposure than after an entire protocol composed of several sessions. Only two studies investigated effect during and/or after one intermittent hypoxia in older individuals in association with cardiovascular outcomes [ 123 , 124 ]. Liu et al (2020) reported that the cerebrovascular response to hypoxia was diminished with age [ 123 ].…”

“…These findings confirm previous results showing a decreased cerebrovascular reactivity to hypoxia in older individuals, compared to young ones, during 5 min isocapnic hypoxic exposure [ 106 ]. Regarding blood pressure, no reduction was reported in pre-hypertensive older people after only one session of intermittent hypoxia [ 124 ]. However, in healthy older individuals, intermittent hypoxia reduced systolic blood pressure and diastolic blood pressure during the first and the last bout (5 bouts in total) of the first session [ 123 ].…”

Respiratory muscle endurance training improves exercise performance but does not affect resting blood pressure and sleep in healthy active elderly

“…An alternative form of exercise that does not involve lower or upper limbs and that can therefore be performed independently of mobility status is respiratory muscle endurance training (RMET). When RMET is performed at near maximal intensities, respiratory muscle O 2 consumption can account for up to 15% of whole-body maximal oxygen consumption (Aaron et al 1992), and average heart rate (HR) during a training session can increases to ~ 60% of predicted HR max in some individuals (Stutz et al 2020). Considering that brisk walking on level ground, which can elicit similar HR responses to RMET, has been shown to lower resting BP in elderly with systolic BP > 120 mmHg (Mandini et al 2018), one can argue that RMET intensity is sufficient to lower resting BP, but this remains to be tested.…”