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Exercise-mediated vasodilation in human obesity and metabolic syndrome: effect of acute ascorbic acid infusion.
- Source :
-
American journal of physiology. Heart and circulatory physiology [Am J Physiol Heart Circ Physiol] 2014 Sep 15; Vol. 307 (6), pp. H840-7. Date of Electronic Publication: 2014 Jul 18. - Publication Year :
- 2014
-
Abstract
- We tested the hypothesis that infusion of ascorbic acid (AA), a potent antioxidant, would alter vasodilator responses to exercise in human obesity and metabolic syndrome (MetSyn). Forearm blood flow (FBF, Doppler ultrasound) was measured in lean, obese, and MetSyn adults (n = 39, 32 ± 2 yr). A brachial artery catheter was inserted for blood pressure monitoring and local infusion of AA. FBF was measured during dynamic handgrip exercise (15% maximal effort) with and without AA infusion. To account for group differences in blood pressure and forearm size, and to assess vasodilation, forearm vascular conductance (FVC = FBF/mean arterial blood pressure/lean forearm mass) was calculated. We examined the time to achieve steady-state FVC (mean response time, MRT) and the rise in FVC from rest to steady-state exercise (Δ, exercise - rest) before and during acute AA infusion. The MRT (P = 0.26) and steady-state vasodilator responses to exercise (ΔFVC, P = 0.31) were not different between groups. Intra-arterial infusion of AA resulted in a significant increase in plasma total antioxidant capacity (174 ± 37%). AA infusion did not alter MRT or steady-state FVC in any group (P = 0.90 and P = 0.85, respectively). Interestingly, higher levels of C-reactive protein predicted longer MRT (r = 0.52, P < 0.01) and a greater reduction in MRT with AA infusion (r = -0.43, P = 0.02). We concluded that AA infusion during moderate-intensity, rhythmic forearm exercise does not alter the time course or magnitude of exercise-mediated vasodilation in groups of young lean, obese, or MetSyn adults. However, systemic inflammation may limit the MRT to exercise, which can be improved with AA.<br /> (Copyright © 2014 the American Physiological Society.)
- Subjects :
- Adolescent
Adult
Arterial Pressure
Biomarkers blood
Blood Flow Velocity
Brachial Artery physiopathology
C-Reactive Protein metabolism
Female
Humans
Inflammation Mediators blood
Infusions, Intra-Arterial
Male
Metabolic Syndrome blood
Metabolic Syndrome diagnosis
Obesity blood
Obesity diagnosis
Regional Blood Flow
Time Factors
Young Adult
Antioxidants administration & dosage
Ascorbic Acid administration & dosage
Brachial Artery drug effects
Exercise
Forearm blood supply
Metabolic Syndrome physiopathology
Obesity physiopathology
Vasodilation drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 1522-1539
- Volume :
- 307
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Heart and circulatory physiology
- Publication Type :
- Academic Journal
- Accession number :
- 25038148
- Full Text :
- https://doi.org/10.1152/ajpheart.00312.2014