Acute dietary nitrate does not reduce resting metabolic rate or oxidative stress marker 8-isoprostane in healthy males and females.

To investigate changes in resting metabolic rate and 8-isoprostane, an oxidative stress biomarker, following acute dietary nitrate supplementation in healthy males and females. In a randomised, double-blind, cross-over study, 10 males and seven females (age range 19-25 years) underwent protocol familiarisation (visit 1), baseline assessments (visits 2 and 4) and assessments following supplementation, placebo or 6.2 mmol nitrate, 2 hours prior to visits 3 and 5. Participants completed a 30-minute RMR test with visits 2 and 3 on consecutive days, separated by a week-long washout period concluding with visits 4 and 5 on consecutive days. Plasma nitrate/nitrite (NOx) significantly increased (p ≤ 0.05) following dietary nitrate consumption compared to baseline values. No significant effect on resting metabolism (p = 0.194) or 8-isoprostane (p = 0.660) was observed following dietary nitrate supplementation. Dietary nitrate increases NO bioavailability, but acute supplementation does not effect resting metabolism or 8-isoprostane in healthy males and females.

Comparison between cuff-based and radial tonometry exercise-induced central blood pressure.

PURPOSE: Non-invasive central blood pressure assessed during exercise may provide better cardiovascular prognostic than measurements taken at rest. Radial tonometry is the only technique validated to perform this type of assessment; however, it relies on the experience of the tester. Cuff-based devices have been developed to avoid operator dependency, although these systems have yet to be validated during exercise. The purpose of this study was to compare exercise-induced central blood pressure estimations between a cuff-based device and radial tonometry. METHODS: Twenty young healthy subjects were recruited to perform a three-workload steady-state exercise test at blood lactate levels of < 2, 2-4, and > 4 mmol/L, respectively. Central systolic and diastolic blood pressure (cSBP and cDBP, respectively), central pulse pressure (cPP), and augmentation index (AIx) were assessed at rest and during each workload with a cuff-based device and radial tonometry. Statistical analysis included Bland-Altman analysis for agreement between techniques. Agreement was considered when 95% of the data set for each central blood pressure parameter was within 1.96 standard deviations from the mean difference. Significance was considered at α = 0.05. RESULTS: Central blood pressure measurements with the cuff device were obtained only at rest and during low-intensity exercise. During low-intensity exercise, all measurements showed agreement between both devices (cSBP 95% CI [- 6.0 to 10.7], cDBP 95% CI [- 4.5 to 6.3], cPP 95% CI [- 4.7 to 8.3], and AIx (95% CI [- 20.1 to 22.2]). CONCLUSION: A cuff-based device can estimate central blood pressure at low-intensity exercise, without operator dependency, and showing agreement to radial tonometry.