Background
High‐resistance inspiratory muscle strength training (IMST) is a novel, time‐efficient physical training modality.
Methods and Results
We performed a double‐blind, randomized, sham‐controlled trial to investigate whether 6 weeks of IMST (30 breaths/day, 6 days/week) improves blood pressure, endothelial function, and arterial stiffness in midlife/older adults (aged 50–79 years) with systolic blood pressure ≥120 mm Hg, while also investigating potential mechanisms and long‐lasting effects. Thirty‐six participants completed high‐resistance IMST (75% maximal inspiratory pressure, n=18) or low‐resistance sham training (15% maximal inspiratory pressure, n=18). IMST was safe, well tolerated, and had excellent adherence (≈95% of training sessions completed). Casual systolic blood pressure decreased from 135±2 mm Hg to 126±3 mm Hg (
P
<0.01) with IMST, which was ≈75% sustained 6 weeks after IMST (
P
<0.01), whereas IMST modestly decreased casual diastolic blood pressure (79±2 mm Hg to 77±2 mm Hg,
P
=0.03); blood pressure was unaffected by sham training (all
P
>0.05). Twenty‐four hour systolic blood pressure was lower after IMST versus sham training (
P
=0.01). Brachial artery flow‐mediated dilation improved ≈45% with IMST (
P
<0.01) but was unchanged with sham training (
P
=0.73). Human umbilical vein endothelial cells cultured with subject serum sampled after versus before IMST exhibited increased NO bioavailability, greater endothelial NO synthase activation, and lower reactive oxygen species bioactivity (
P
<0.05). IMST decreased C‐reactive protein (
P
=0.05) and altered select circulating metabolites (targeted plasma metabolomics) associated with cardiovascular function. Neither IMST nor sham training influenced arterial stiffness (
P
>0.05).
Conclusions
High‐resistance IMST is a safe, highly adherable lifestyle intervention for improving blood pressure and endothelial function in midlife/older adults with above‐normal initial systolic blood pressure.
Registration
URL:
https://www.clinicaltrials.gov
; Unique identifier: NCT03266510.
Oral vitamin C restores endothelial function during acute inflammation in young and older adults
