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.

Cardiovascular diseases (CVD) remain the leading cause of death in developed societies, and “midlife” (50–64 yr) and older (65+) men and women bear the great majority of the burden of CVD. Much of the increased risk of CVD in this population is attributable to CV dysfunction, including adverse changes in the structure and function of the heart, increased systolic blood pressure, and arterial dysfunction. The latter is characterized by increased arterial stiffness and vascular endothelial dysfunction. Conventional aerobic exercise training, as generally recommended in public health guidelines, is an effective strategy to preserve or improve CV function with aging. However, <40% of midlife and older adults meet aerobic exercise guidelines, due in part to time availability-related barriers. As such, there is a need to develop evidence-based time-efficient exercise interventions that promote adherence and optimize CV function in these groups. Two promising interventions that may meet these criteria are interval training and inspiratory muscle strength training (IMST). Limited research suggests these modes of training may improve CV function with time commitments of ≤60 min/wk. This review will summarize the current evidence for interval training and IMST to improve CV function in midlife/older adults and identify key research gaps and future directions.

The Pacific Crest Trail (PCT) is a 4265‐km hiking trail that extends from the US‐Mexican border to the US‐Canadian border through the mountain ranges of western North America. Individuals who hike the entire length of the trail in one season (4–6 months) perform long daily exercise durations while exposed to extreme environmental temperatures, high altitudes, intense solar radiation, and the consumption of calorie‐rich, nutrient‐poor diets. This case study reports changes in arterial function and body composition in a subject before and after a 112‐day long‐distance hike of the PCT. Brachial artery flow‐mediated dilation, a measure of vascular endothelial function, decreased from: 6.97% to 5.00%. Carotid‐femoral pulse wave velocity, a measure of aortic stiffness, increased from 5.39 to 5.76 m/s. Dual‐energy x‐ray absorptiometry scans detected no major changes in total‐body bone mineral density, fat mass, or lean mass, although there were minor, unfavorable changes in some subregions of the body. It is important for individuals completing a long‐distance hike to be aware of the potential deleterious changes associated with large volumes of exercise and consuming a high‐calorie, low‐quality diet.

BackgroundThe majority of middle‐aged to older adults have above‐normal systolic blood pressure (SBP), i.e., SBP ≥120 mmHg, placing them at an increased risk for cardiovascular diseases, cognitive dysfunction, chronic kidney disease, and other chronic conditions of aging. This elevated SBP state is associated with the vascular risk factors endothelial dysfunction and stiffening of the large elastic (i.e., aorta and carotid) arteries. High‐intensity short‐duration inspiratory muscle strength training (IMST) represents a novel, time‐efficient (~5 min/day) lifestyle intervention that lowers SBP in select patient populations. However, whether IMST lowers SBP in middle‐aged to older adults with above‐normal SBP, or improves arterial function in any population, remains unknown.PurposeTo determine whether high‐intensity short‐duration IMST lowers SBP and improves arterial function in otherwise healthy middle‐aged to older adults with above‐normal SBP.MethodsThirteen middle‐aged and older (50–79 years) men and post‐menopausal women with resting SBP ≥120 mmHg underwent 6 weeks of IMST (30 breaths/day; 6 days/week; 75% maximum inspiratory pressure [PIMAX]) (n=7, 2M/5F, age: 68 ± 2 years) or sham (15% PIMAX) training (n=6, 3M/3F, age: 67 ± 3 years) in a randomized, double‐blind, sham‐controlled study. Subjects underwent testing for BP (resting and 24‐hour ambulatory [AMBP]), vascular endothelial function (brachial artery flow‐mediated dilation [FMDBA]) and arterial stiffness (carotid‐femoral pulse wave velocity [CFPWV], carotid artery compliance and β‐stiffness index) before and after the intervention.ResultsResting SBP was significantly lower after vs. before IMST (pre: 137 ± 4 mmHg, post: 127 ± 5 mmHg; p=0.001), but not sham training (pre: 134 ± 5 mmHg, post: 130 ± 5 mmHg; p=0.13). No changes in resting diastolic BP (DBP) or AMBP (24‐hour, daytime, and nighttime measures of SBP and DBP) were observed in either group (all p>0.05). FMDBA was increased after IMST (pre: 4.2 Δ%, post: 6.3 Δ%; p=0.001), but not in response to sham training (pre: 3.2 Δ%, post: 3.2 Δ%; p=0.99), such that FMDBA was significantly higher in the IMST group compared to sham post‐intervention (p=0.01). There were no changes in CFPWV, or carotid artery compliance or β‐stiffness with training in either group (all p>0.05), nor were body weight, body composition, fasting plasma lipids or fasting blood glucose concentrations altered with IMST or sham training (all p>0.05).ConclusionThese findings suggest that, independent of changes in other conventional CVD risk factors, high‐intensity short‐duration IMST may be an effective lifestyle‐based approach to lower resting (casual) SBP and improve vascular endothelial function in middle‐aged and older men and women with above‐normal initial levels of resting SBP.Support or Funding InformationAHA 18POST33990034, T32 DK007135, UL1 TR002535This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

BackgroundCardiorespiratory fitness declines with aging and is a strong independent risk factor for future morbidity and mortality. Conventional aerobic exercise improves cardiorespiratory fitness in middle‐aged and older (MA/O) adults, but is associated with relatively low adherence, due, in part, to significant time requirements (150 min/week). High‐resistance, short‐duration inspiratory muscle strength training (IMST) requires only 30 min/week and is associated with excellent adherence, but effects on cardiorespiratory fitness are unknown. We assessed whether high‐resistance, short‐duration IMST improves cardiorespiratory fitness assessed under maximal exercise (VO2max, exercise tolerance) and standardized submaximal exercise conditions.MethodsHealthy, recreationally active MA/O adults (50–79 years) were recruited. Subjects were randomly assigned to perform 6‐weeks of IMST (30 breaths/day; 6 days/week; 75% maximum inspiratory pressure [PIMAX]) (n=7 age: 68 ± 2 years) or sham (15% PIMAX) training (n=7; age: 67 ± 3 years) in a randomized, double‐blind, placebo‐controlled study. Oxygen uptake (VO2) and other responses were measured throughout incremental treadmill exercise to exhaustion using a modified Balke Protocol pre‐ and post‐intervention.ResultsAdherence, defined as percentage of prescribed training sessions completed, was high in both the IMST (100%) and sham (98%) groups. PIMAX increased in the IMST group (pre: 57 ± 5, post: 70 ± 4 mmHg; p=0.048) but not sham group (pre: 54 ± 2, post: 60 ± 1 mmHg; p=0.5). VO2max did not change with training in either group (p>0.05), but exercise time to exhaustion increased by 15% in the IMST group (pre: 629 ± 64, post: 726 ± 50 seconds; p=0.009) and decreased in the sham group (pre: 583 ± 74, post: 500 ± 77 seconds; p=0.02). At maximal exercise, most markers of voluntary effort (minute ventilation, VE, heart rate, HR, and rating of perceived exertion, RPE) were unchanged pre vs. post training in both groups (all p>0.05), but peak respiratory exchange ratio, a measure of hyperventilation, was higher in the IMST group after training (pre: 1.08 ± 0.03, post: 1.14 ± 0.03; p=0.05; sham group: pre: 1.06 ± 0.02, post: 1.05 ± 0.04; p=0.96). At a fixed submaximal workload (~80% of initial VO2max), VO2 (pre: 23.3 ± 1.8, post: 21.3 ± 1.5 ml/kg/min; p=0.01) and HR (pre: 131 ± 7, post: 127 ± 7; p=0.07) were lower after vs. before IMST, but unchanged with sham training. VE and RPE during submaximal exercise were unchanged with training in both groups (all p>0.05).ConclusionHigh‐resistance short‐duration IMST increases exercise time to exhaustion (exercise tolerance), improves submaximal exercise economy, and lowers HR during submaximal exercise in healthy, recreationally active, MA/O adults. Thus, high resistance, short‐duration IMST improves exercise performance in healthy MA/O adults, and may hold even greater promise for older adults with functional limitations and/or chronic disease.Support or Funding InformationAHA 18POST33990034, T32 DK007135, UL1 TR002535This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.