title: Acute L-arginine supplementation reduces the O2 cost of moderate-intensity exercise and enhances high-intensity exercise tolerance.
abstract: It has recently been reported that dietary nitrate (NO(3)(-)) supplementation, which increases plasma nitrite (NO(2)(-)) concentration, a biomarker of nitric oxide (NO) availability, improves exercise efficiency and exercise tolerance in healthy humans. We hypothesized that dietary supplementation with L-arginine, the substrate for NO synthase (NOS), would elicit similar responses. In a double-blind, crossover study, nine healthy men (aged 19-38 yr) consumed 500 ml of a beverage containing 6 g of l-arginine (Arg) or a placebo beverage (PL) and completed a series of "step" moderate- and severe-intensity exercise bouts 1 h after ingestion of the beverage. Plasma NO(2)(-) concentration was significantly greater in the Arg than the PL group (331 ± 198 vs. 159 ± 102 nM, P < 0.05) and systolic blood pressure was significantly reduced (123 ± 3 vs. 131 ± 5 mmHg, P < 0.01). The steady-state O(2) uptake (VO(2)) during moderate-intensity exercise was reduced by 7% in the Arg group (1.48 ± 0.12 vs. 1.59 ± 0.14 l/min, P < 0.05). During severe-intensity exercise, the Vo(2) slow component amplitude was reduced (0.58 ± 0.23 and 0.76 ± 0.29 l/min in Arg and PL, respectively, P < 0.05) and the time to exhaustion was extended (707 ± 232 and 562 ± 145 s in Arg and PL, respectively, P < 0.05) following consumption of Arg. In conclusion, similar to the effects of increased dietary NO(3)(-) intake, elevating NO bioavailability through dietary L-Arg supplementation reduced the O(2) cost of moderate-intensity exercise and blunted the VO(2) slow component and extended the time to exhaustion during severe-intensity exercise.
authors: School of Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom.
authors: Stephen J
authors: SJ
authors: Bailey
authors: Paul G
authors: PG
authors: Winyard
authors: Anni
authors: A
authors: Vanhatalo
authors: Jamie R
authors: JR
authors: Blackwell
authors: Fred J
authors: FJ
authors: DiMenna
authors: Daryl P
authors: DP
authors: Wilkerson
authors: Andrew M
authors: AM
authors: Jones
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001120:Arginine / Q000008:administration & dosage* / Q000378:metabolism; D001628:Beverages; D001794:Blood Pressure; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004739:England; D015444:Exercise; D017079:Exercise Tolerance / Q000187:drug effects*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects*; D011659:Pulmonary Gas Exchange; D013997:Time Factors; D055815:Young Adult
chemical_list: D009573:Nitrites; D009569:Nitric Oxide; D001120:Arginine