title: No effect of dietary nitrate supplementation on endurance training in hypoxia.
abstract: We investigated whether dietary nitrate (NO(3)(-)) supplementation enhances the effect of training in hypoxia on endurance performance at sea level. Twenty-two healthy male volunteers performed high-intensity endurance training on a cycle ergometer (6 weeks, 5×30 min/week at 4-6 mmol/L blood lactate) in normobaric hypoxia (12.5% FiO(2)), while ingesting either beetroot juice [0.07 mmol NO(3)(-) /kg body weight (bw)/day; BR, n = 11] or a control drink (CON, n = 11). During the pretest and the posttest, the subjects performed a 30-min simulated time trial (TT) and an incremental VO(2max) test. Furthermore, a biopsy was taken from m. vastus lateralis before and after the TT. Power output during the training sessions in both groups increased by ∼6% from week 1 to week 6 (P < 0.05). Compared with the pretest, VO(2max) in the posttest was increased (P < 0.05) in CON (5%) and BR (9%). Power output corresponding with the 4 mmol/L blood lactate threshold, as well as mean power output during TT increased by ∼16% in both groups (P < 0.05). Muscle phospho-AMP-activated protein kinase, hypoxia inducible factor-1α mRNA content, and glycogen breakdown during the TT were similar between the groups in both the pretest and the posttest. In conclusion, low-dose dietary NO(3)(-) supplementation does not enhance the effects of intermittent hypoxic training on endurance exercise performance at sea level.
authors.affiliation: Exercise Physiology Research Group, Department of Kinesiology, KU Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Puype
authors.forename: M
authors.initials: M
authors.lastname: Ramaekers
authors.forename: R
authors.initials: R
authors.lastname: Van Thienen
authors.forename: L
authors.initials: L
authors.lastname: Deldicque
authors.forename: P
authors.initials: P
authors.lastname: Hespel
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000531:Altitude; D027461:Beta vulgaris; D001642:Bicycling / Q000502:physiology*; D015153:Blotting, Western; D019587:Dietary Supplements; D005080:Exercise Test; D000067030:Fruit and Vegetable Juices; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism; D009566:Nitrates / Q000008:administration & dosage / Q000494:pharmacology* / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology; D052097:Quadriceps Muscle / Q000187:drug effects / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D009124:Muscle Proteins; D009566:Nitrates
keywords: Nitric oxide; aerobic capacity; altitude; high-intensity endurance training