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Role of reactive oxygen species on blood pressure and exercise hyperemia in aging humans: effect of lifelong physical activity
Author(s) -
Nyberg Michael,
Saltin Bengt,
Hellsten Ylva,
Mortensen Stefan Peter
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1049.4
Subject(s) - sed , reactive hyperemia , vasodilation , blood pressure , bioavailability , chemistry , nitric oxide , reactive oxygen species , medicine , hemodynamics , endocrinology , vo2 max , antioxidant , physical exercise , pharmacology , heart rate , biochemistry
This study examined whether reduced nitric oxide (NO) bioavailability, caused by formation of reactive oxygen species (ROS), is less in well‐trained than in un‐trained elderly individuals. We measured hemodynamics at rest and during one‐leg knee‐extensor exercise (12 W and 45 % of Wmax) in lifelong sedentary (SED; 63±4 years; Wmax of 45±4 W) and lifelong physically active (AC; 64±3 years; Wmax of 76±11 W) male subjects without (CON) or with infusion of the antioxidant N‐acetylcysteine (NAC; 125mg kg‐1 h‐1 for 15 min followed by 25mg kg‐1 h‐1 until the termination of exercise) in order to scavenge ROS. During CON there was no difference in leg blood flow (LBF) at 12 W between SED and AC (1.72±0.08 and 1.64±0.06 l min‐1, respectively) and infusion of NAC did not change LBF in either group. Mean arterial pressure (MAP) at rest and during exercise at 12 W was lower (P<0.05) in both AC and SED during NAC infusion, whereas MAP also decreased (P<0.05) during 45 % of Wmax in AC. Infusion of NAC increased (P<0.05) leg vascular conductance at 12 W in AC. These results indicate that an elevated formation of ROS affects the bioavailability of NO leading to elevations in blood pressure in both lifelong sedentary and physically active individuals. Moreover, physical activity appears to augment the vasodilator potency of NO during low intensity muscle contraction.