Isometric handgrip training does not improve flow-mediated dilation in subjects with normal blood pressure

2007 ◽  
Vol 112 (7) ◽  
pp. 403-409 ◽  
Author(s):  
Cheri L. Mcgowan ◽  
Andrew S. Levy ◽  
Neil Mccartney ◽  
Maureen J. Macdonald

Isometric HG (handgrip) training lowers resting arterial BP (blood pressure), yet the mechanisms are elusive. In the present study, we investigated improved systemic endothelial function as a mechanism of arterial BP modification following isometric HG training in normotensive individuals. This study employed a within-subject repeated measures design primarily to assess improvements in BA FMD (brachial artery flow-mediated dilation; an index of endothelium-dependent vasodilation), with the non-exercising limb acting as an internal control. Eleven subjects performed four 2-min unilateral isometric HG contractions at 30% of maximal effort, three times per week for 8 weeks. Pre-, mid- and post-training resting ABP and BA FMD (exercised arm and non-exercised arm) were measured via automated brachial oscillometry and ultrasound respectively. BA FMD (normalized to the peak shear rate experienced in response to the reactive hyperaemic stimulus) remained unchanged [exercised arm, 0.029±0.003 to 0.026±0.003 to 0.029±0.004%/s−1 (pre- to mid- to post-training respectively); non-exercised arm, 0.023±0.003 to 0.023±0.003 to 0.024±0.003%/s−1 (pre- to mid- to post-training respectively); P=0.22]. In conclusion, improved systemic endothelial function is unlikely to be responsible for lowering arterial BP in this population.

2016 ◽  
Vol 310 (5) ◽  
pp. H648-H653 ◽  
Author(s):  
Robert M. Restaino ◽  
Lauren K. Walsh ◽  
Takuma Morishima ◽  
Jennifer R. Vranish ◽  
Luis A. Martinez-Lemus ◽  
...  

We and others have recently reported that prolonged sitting impairs endothelial function in the leg vasculature; however, the mechanism(s) remain unknown. Herein, we tested the hypothesis that a sustained reduction in flow-induced shear stress is the underlying mechanism by which sitting induces leg endothelial dysfunction. Specifically, we examined whether preventing the reduction in shear stress during sitting would abolish the detrimental effects of sitting on popliteal artery endothelial function. In 10 young healthy men, bilateral measurements of popliteal artery flow-mediated dilation were performed before and after a 3-h sitting period during which one foot was submerged in 42°C water (i.e., heated) to increase blood flow and thus shear stress, whereas the contralateral leg remained dry and served as internal control (i.e., nonheated). During sitting, popliteal artery mean shear rate was reduced in the nonheated leg (pre-sit, 42.9 ± 4.5 s−1; and 3-h sit, 23.6 ± 3.3 s−1; P < 0.05) but not in the heated leg (pre-sit, 38.9 ± 3.4 s−1; and 3-h sit, 63.9 ± 16.9 s−1; P > 0.05). Popliteal artery flow-mediated dilation was impaired after 3 h of sitting in the nonheated leg (pre-sit, 7.1 ± 1.4% vs. post-sit, 2.8 ± 0.9%; P < 0.05) but not in the heated leg (pre-sit: 7.3 ± 1.5% vs. post-sit, 10.9 ± 1.8%; P > 0.05). Collectively, these data suggest that preventing the reduction of flow-induced shear stress during prolonged sitting with local heating abolishes the impairment in popliteal artery endothelial function. Thus these findings are consistent with the hypothesis that sitting-induced leg endothelial dysfunction is mediated by a reduction in shear stress.


2015 ◽  
Vol 118 (12) ◽  
pp. 1510-1515 ◽  
Author(s):  
Evan L. Matthews ◽  
Michael S. Brian ◽  
Meghan G. Ramick ◽  
Shannon Lennon-Edwards ◽  
David G. Edwards ◽  
...  

Recent studies demonstrate that high dietary sodium (HS) impairs endothelial function in those with salt-resistant (SR) blood pressure (BP). The effect of HS on endothelial function in those with salt-sensitive (SS) BP is not currently known. We hypothesized that HS would impair brachial artery flow-mediated dilation (FMD) to a greater extent in SS compared with SR adults. Ten SR (age 42 ± 5 yr, 5 men, 5 women) and 10 SS (age 39 ± 5 yr, 5 men, 5 women) healthy, normotensive participants were enrolled in a controlled feeding study consisting of a run-in diet followed by a 7-day low dietary sodium (LS) (20 mmol/day) and a 7-day HS (300 mmol/day) diet in random order. Brachial artery FMD and 24-h BP were assessed on the last day of each diet. SS BP was individually assessed and defined as a change in 24-h mean arterial pressure (MAP) of >5 mmHg between the LS and HS diets (ΔMAP: SR −0.6 ± 1.2, SS 7.7 ± 0.4 mmHg). Brachial artery FMD was lower in both SS and SR individuals during the HS diet ( P < 0.001), and did not differ between groups ( P > 0.05) (FMD: SR LS 10.6 ± 1.3%, SR HS 7.2 ± 1.5%, SS LS 12.5 ± 1.7%, SS HS 7.8 ± 1.4%). These data indicate that an HS diet impairs brachial artery FMD to a similar extent in adults with SS BP and SR BP.


2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Sebastien Lacroix ◽  
Christine Des Rosiers ◽  
Mathieu Gayda ◽  
Anil Nigam

Background: Endothelial dysfunction is considered a precursor of atherosclerosis and is an independent predictor of cardiovascular events. A high-saturated fat meal (HFM) has been shown to induce postprandial endothelial dysfunction. However, no studies have evaluated the acute endothelial effect of a single mixed Mediterranean-type meal (MMM). Our objective was to evaluate postprandial endothelial and metabolic function in response to a MMM in comparison to an isocaloric HFM. Methods: In this ongoing crossover study, 26 of 28 healthy non-smoking males have completed the research protocol. In random order on two separate days during a 1-week interval, subjects were fed two isocaloric meals after an overnight fast. The MMM (885 kcal) consisted of fresh salmon, almonds and vegetables baked in olive oil providing 51% of total calories from fat (7.87g SFA and 2.29g of omega-3, 2:1 DHA:EPA). The HFM consisted of a McDonald’s sausage, egg and cheese McMuffin and three hashbrowns (858 kcal) providing 58% of total energy from fat (14.78g SFA and no omega-3). Endothelial function was evaluated by measuring brachial artery flow-mediated dilation (%FMD) at baseline and at two (T2) and four (T4) hours postprandial. Results: Mean postprandial %FMD tends to be less impaired following the MMM than the HFM (variation at T4 -0.15±3.6% vs -2.83±3.3% respectively, p<0.1). Postprandial variations of TG and TG/HDL at T4 were also less severe with the MMM than the HFM (p≤0.05) and did not correlate to %FMD variations. When subdividing the population on the basis of the median fasting TG levels (0.90 mmol/L), the HFM led to significant endothelial impairment in the subjects with higher-TG while it had no effect in the low-TG group. Conclusion: Our data suggest that a single MMM exerts less of a deleterious effect on postprandial endothelial function and metabolic markers than does a HFM. A single MMM could thus be less atherogenic than a HFM. Moreover, subjects with higher fasting TG levels (avg. 1.54±0.59 mmol/L, well bellow hypertriglyceridemia threshold) could be at higher risk of endothelial injury following a single HFM. Data on all 28 subjects will be available in April 2012.


Hypertension ◽  
2021 ◽  
Vol 77 (1) ◽  
pp. 241-251
Author(s):  
Sarah C. Couch ◽  
Brian E. Saelens ◽  
Philip R. Khoury ◽  
Katherine B. Dart ◽  
Kelli Hinn ◽  
...  

This randomized control trial assessed the post-intervention and 18-month follow-up effects of a 6-month dietary approaches to stop hypertension (DASH)-focused behavioral nutrition intervention, initiated in clinic with subsequent telephone and mail contact, on blood pressure (BP) and endothelial function in adolescents with elevated BP. Adolescents (n=159) 11 to 18 years of age with newly diagnosed elevated BP or stage 1 hypertension treated at a hospital-based clinic were randomized. DASH participants received a take-home manual plus 2 face-to-face counseling sessions at baseline and 3 months with a dietitian regarding the DASH diet, 6 monthly mailings, and 8 weekly and then 7 biweekly telephone calls focused on behavioral strategies to promote DASH adherence. Routine care participants received nutrition counseling with a dietitian consistent with pediatric guidelines established by the National High Blood Pressure Education Program. Outcomes, measured pre- and post-intervention and at 18-months follow-up, included change in BP, change in brachial artery flow-mediated dilation, and change in DASH score based on 3-day diet recalls. Adolescents in DASH versus routine care had a greater improvement in systolic BP (–2.7 mm Hg, P = 0.03, –0.3 z-score, P =0.03), flow-mediated dilation (2.5%, P =0.05), and DASH score (13.3 points, P <0.0001) from baseline to post-treatment and a greater improvement in flow-mediated dilation (3.1%, P =0.03) and DASH score (7.4 points, P =0.01) to 18 months. The DASH intervention proved more effective than routine care in initial systolic BP improvement and longer term improvement in endothelial function and diet quality in adolescents with elevated BP and hypertension. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT00585832.


2020 ◽  
Vol 9 (17) ◽  
Author(s):  
Teresa K. Chen ◽  
Ronit Katz ◽  
Michelle M. Estrella ◽  
Wendy S. Post ◽  
Holly Kramer ◽  
...  

Background APOL1 high‐risk genotypes are associated with increased risk for hypertension‐attributed kidney disease among Black adults in the United States. Biopsy studies show differences in kidney vasculature by APOL1 status; less is known about the variants' associations with systemic vascular and endothelial function. Whether APOL1 risk variants are associated with blood pressure (BP) is also uncertain. Methods and Results Using linear regression, we examined cross‐sectional associations of APOL1 risk genotypes (high=2 risk alleles, low=0 or 1 risk allele) with subclinical measures of vascular function (small arterial elasticity, n=1586; large arterial elasticity, n=1586; ascending aortic distensibility, n=985) and endothelial function (flow‐mediated dilation, n=777). Using linear mixed‐effects models, we studied longitudinal associations of APOL1 risk genotypes with BP (n=1619), adjusting for age, sex, and African ancestry. Among 1619 (12% APOL1 high‐risk) Black participants in MESA (Multi‐Ethnic Study of Atherosclerosis), mean age was 62 years old, 58% had hypertension, and mean systolic BP was 131 mm Hg at baseline. At examination 1 (2000–2002), there was no significant difference in small arterial elasticity, large arterial elasticity, ascending aortic distensibility, or flow‐mediated dilation in participants with APOL1 high‐ versus low‐risk genotypes ( P >0.05 for all). Over a mean follow‐up of 7.8 years, relative annual changes in systolic and diastolic BP and pulse pressure did not differ significantly by APOL1 risk status (between‐group differences of −0.20, −0.14, and −0.25, respectively; P >0.05 for all). Conclusions Among Black participants in MESA, APOL1 high‐risk genotypes were not associated with subclinical vascular and endothelial function or BP trajectories. The relationship of APOL1 with kidney disease may be intrinsic to the kidney rather than through peripheral effects on systemic vasculature or BP.


1989 ◽  
Vol 33 (10) ◽  
pp. 625-629
Author(s):  
Mary L. Rankin ◽  
Georgia Latham ◽  
Robert D. Peters ◽  
David M. Penetar

Previous research regarding the effects of sleep deprivation (SD) on human physiology and mood has yielded conflicting results. These findings may in part be due to the use of small sample sizes and the failure to separate out the pure effects of SD from those of circadian rhythms during data analysis. One purpose of this study was to clearly identify the effects of 48 hours of SD on blood pressure, temperature, heart rate, and mood by overcoming the limitations of previous research. A second purpose was to evaluate the effects of SD on recognition memory. A repeated measures design was employed to collect physiological, mood, and memory data over a 48 hour period. While strong circadian rhythms were observed for most of the physiological and mood variables, recognition memory was unaffected by 48 hours of SD.


Author(s):  
Matthew C Babcock ◽  
Lyndsey E. DuBose ◽  
Teresa L. Witten ◽  
Ashley Brubaker ◽  
Brian L. Stauffer ◽  
...  

Aging is associated with reductions in endothelial function, observations primarily reported using brachial artery ultrasound. There is growing interest in the use of peripheral artery tonometry (PAT) of microvessels in the fingertip to assess endothelial function because it is less technically demanding and has a high sensitivity and specificity for assessing coronary endothelial function. Moreover, similar to brachial artery flow mediated dilation (FMD), PAT predicts cardiovascular disease (CVD) outcomes. However, the relation between PAT and FMD have yet to be examined in the context of aging. To address this question, reactive hyperemic index (RHI) using EndoPAT and flow-mediated dilation (FMD) using brachial artery ultrasound were assessed after five minutes of forearm ischemia in twenty younger (18-40 years old; 29±4 years) and twenty older (60-75 years old; 65±4 years) healthy adult men. Higher values of both FMD and RHI indicate better endothelial function. Endothelial function assessed via brachial artery FMD was lower in older (4.8±2.1%), compared to younger (7.5±1.6%) men (p<0.001). In contrast, the RHI assessed via PAT was greater in older (2.2±0.6), compared to younger (1.8±0.5) men (p=0.014). FMD and RHI were not correlated (r=-0.15; p=0.35). We conclude that PAT may not be an appropriate measure to evaluate age-associated changes in endothelial function.


2020 ◽  
Vol 150 (9) ◽  
pp. 2287-2294 ◽  
Author(s):  
Lu Li ◽  
Gemma K Lyall ◽  
J Alberto Martinez-Blazquez ◽  
Fernando Vallejo ◽  
Francisco A Tomas-Barberan ◽  
...  

ABSTRACT Background Epidemiological studies have indicated an inverse association between citrus fruit consumption and cardiovascular disease (CVD) risk. There is, however, a paucity of data concerning effects of blood orange juice (BOJ) intake on endothelial function and cardiovascular risk biomarkers. Objectives We examined short-term effects of BOJ on endothelial function, blood pressure, lipid profile, and inflammatory markers in healthy participants of European origin who were overweight or obese. Methods In a randomized, controlled, single-blind, crossover trial, 15 men and women (age: 28.7 ± 6.5 y; BMI: 28.3 ± 3.1 kg/m2) consumed BOJ or a sugar-matched control drink (CD) (200 mL twice daily) for 2 wk with a washout period of 1 wk. Endothelial function, measured as flow-mediated dilation (FMD) (primary outcome), and the secondary outcomes blood pressure, anthropometric measures, lipid profile, inflammatory markers, markers of vasodilation and vasoconstriction, and urinary flavanone metabolites were evaluated prior to and at the end of each treatment period following an overnight fast. Changes between treatments over time were assessed using repeated-measures ANOVA. Results The results demonstrate a significant increase in FMD following BOJ consumption (pre: 8.15% ± 2.92%; post: 10.2% ± 3.31%; P = 0.002) compared with CD (pre: 8.11% ± 2.52%; post: 7.77% ± 2.43%; time × treatment interaction: P = 0.001). Concurrent significant increases in urinary hesperetin-3′-glucuronide and hesperetin-7-glucuronide were observed following BOJ supplementation only (time × treatment interaction: P ≤ 0.01). Baseline blood pressure, lipid profile, high-sensitivity C-reactive protein, and endothelin-1 were generally within healthy ranges and unaffected by the intervention. Conclusions A 2-wk consumption of BOJ exerted favorable effects on endothelial function in healthy women and men who were overweight or obese, which is likely mediated by the combined actions of anthocyanin and flavanone metabolites on mechanisms that contribute to enhancing NO bioavailability. This trial was registered at clinicaltrials.gov as NCT03611114.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Abel Romero Corral ◽  
Justo Sierra-Johnson ◽  
Marek Orban ◽  
Apoor S Gami ◽  
Fatima H Sert Kuniyoshi ◽  
...  

Background: Endothelial dysfunction assessed by flow mediated dilation (FMD) of the brachial artery has been identified as an independent predictor of cardiovascular events. However, whether weight gain impairs endothelial function is unknown. Methods: A randomized blinded controlled-trial to assess the effects of weight gain on endothelial function. After a weight maintenance period supervised by an experience dietitian, volunteers were randomized to gain weight (4 kg) or maintain weight. We recruited lean (BMI 18.5–24.9 kg/m 2 ) healthy volunteers (no diseases, medications and non-smokers) from the community. Using ultrasound, endothelial function was measured by FMD and non-flow mediated dilation (NFMD) of the brachial artery in the early morning (6:30 a.m.). Endothelial function was measured at baseline, after fat gain at 8 weeks and after weight loss at 16 weeks for fat-gainers and at baseline and follow-up (8 weeks) for weight maintainers. Body composition techniques to measure body fat %, such as dual x-ray absorptiometry and abdominal CT scans were performed. Results: We recruited 35 fat-gainers and 8 weight maintainers. Mean age was 29 ± 6 years and 18 (42 %) were women. There were no differences in age, anthropometric and body composition measurements, blood pressure, heart rate or apnea hypopnea index at baseline between both groups. After an average gain of 4 kg, the fat-gainer group significantly increased their total, visceral and subcutaneous fat. Brachial artery FMD and NFMD remained unchanged in weight maintainers. However, it decreaed in fat-gainers (FMD=9.1 ± 3 vs. 7.6 ± 3.2, p=0.003 and NFMD=12.0 ± 4.9 vs. 10.1 ± 6.0, p=0.01), but recovered to baseline after subjects shed the gained weight (basleline vs. recovery: FMD=9.1 ± 3 vs. 9.0 ± 3, p=NS and NFMD =12.0 ± 4.9 vs.12.6 ± 5.0, p=NS). Visceral fat gain, but not subcutaneous fat gain was significantly correlated with the decrease in brachial artery FMD (rho =−0.42, p=0.004 and rho =−0.22, p=0.15, respectively). Conclusions: In lean healthy young subjects, modest weight gain results in impaired endothelial function, even in the absence of changes in blood pressure. Endothelial funcion recovers after weight loss. Viscerar rather than subcutaneous fat predicts endothelial dysfunction.


2018 ◽  
Vol 315 (4) ◽  
pp. H925-H933 ◽  
Author(s):  
Tessa E. Adler ◽  
Charlotte W. Usselman ◽  
Akira Takamata ◽  
Nina S. Stachenfeld

Hypertension, obesity, and endothelial function predict cardiovascular disease in women, and these factors are interrelated. We hypothesized that hypertension and obesity are associated with endothelial dysfunction in young women and that short-term ethinyl estradiol exposure mitigates this dysfunction. We examined flow-mediated dilation (FMD) responses before and during 7 days of oral ethinyl estradiol (30 µg/day) in 19 women (25 ± 5, 18–35 yr). We divided our sample into two groups based on two criteria: blood pressure and obesity. Women were divided into normal blood pressure (NBP; mean arterial pressure range: 78–91 mmHg, n = 7) and high blood pressure (HBP; mean arterial pressure range: 95–113 mmHg, n = 9) groups. We also stratified our subjects by body composition (lean: 18–31%, n = 8; obese: 38–59%, n = 9). We evaluated brachial FMD after two distinct shear stress stimuli: occlusion alone and occlusion with ischemic handgrip exercise. Obesity was unrelated to both FMD responses. Before ethinyl estradiol administration, the HBP group had blunted ischemic exercise responses relative to the NBP group (8.0 ± 3.5 vs. 12.3 ± 3.2%, respectively, P = 0.05). However, during ethinyl estradiol administration, ischemic exercise responses increased in the HBP group (12.8 ± 6.1%, P = 0.04) but decreased in the NBP group (5.6 ± 2.4%, P = 0.01). Standard FMD did not reveal differences between groups. In summary, 1) moderate HBP predicted endothelial impairment, 2) ethinyl estradiol administration had divergent effects on FMD in women with NBP versus HBP, and 3) enhanced FMD (ischemic handgrip exercise) revealed differences in endothelial function, whereas standard FMD (occlusion alone) did not. NEW & NOTEWORTHY We are the first to show that mild hypertension is a stronger predictor of endothelial dysfunction than obesity in healthy women without overt cardiovascular dysfunction. Importantly, the standard 5-min flow-mediated vasodilation stimulus did not detect endothelial dysfunction in our healthy population; only an enhanced ischemic handgrip exercise shear stress stimulus detected endothelial impairment. Estradiol administration increased flow-mediated dilation in women with high blood pressure, so it may be a therapeutic intervention to improve endothelial function.


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