Dietary nitrate accelerates postexercise muscle metabolic recovery and O2 delivery in hypoxia.
Journal of Applied Physiology
American Physiological Society
The final version is available from the American Physiological Society via the DOI in this record.
We tested the hypothesis that the time constants (τ) of postexercise T2* MRI signal intensity (an index of O2 delivery) and muscle [PCr] (an index of metabolic perturbation, measured by (31)P-MRS) in hypoxia would be accelerated after dietary nitrate (NO3 (-)) supplementation. In a double-blind crossover design, eight moderately trained subjects underwent 5 days of NO3 (-) (beetroot juice, BR; 8.2 mmol/day NO3 (-)) and placebo (PL; 0.003 mmol/day NO3 (-)) supplementation in four conditions: normoxic PL (N-PL), hypoxic PL (H-PL; 13% O2), normoxic NO3 (-) (N-BR), and hypoxic NO3 (-) (H-BR). The single-leg knee-extension protocol consisted of 10 min of steady-state exercise and 24 s of high-intensity exercise. The [PCr] recovery τ was greater in H-PL (30 ± 4 s) than H-BR (22 ± 4 s), N-PL (24 ± 4 s) and N-BR (22 ± 4 s) (P < 0.05) and the maximal rate of mitochondrial ATP resynthesis (Qmax) was lower in the H-PL (1.12 ± 0.16 mM/s) compared with H-BR (1.35 ± 0.26 mM/s), N-PL (1.47 ± 0.28 mM/s), and N-BR (1.40 ± 0.21 mM/s) (P < 0.05). The τ of postexercise T2* signal intensity was greater in H-PL (47 ± 14 s) than H-BR (32 ± 10 s), N-PL (38 ± 9 s), and N-BR (27 ± 6 s) (P < 0.05). The postexercise [PCr] and T2* recovery τ were correlated in hypoxia (r = 0.60; P < 0.05), but not in normoxia (r = 0.28; P > 0.05). These findings suggest that the NO3 (-)-NO2 (-)-NO pathway is a significant modulator of muscle energetics and O2 delivery during hypoxic exercise and subsequent recovery.
J. Fulford's salary was supported via National Institute of Health Research Grant 50112.
Journal of Applied Physiology, 2014, Vol. 117, no.12, pp. 1460 - 1470
Place of publication
Showing items related by title, author, creator and subject.
Short-term muscle disuse atrophy is not associated with increased intramuscular lipid deposition or a decline in the maximal activity of key mitochondrial enzymes in young and older males Wall, BT; Dirks, ML; Snijders, T; Stephens, FB; Senden, JMG; Verscheijden, M-L; van Loon, LJC (Elsevier, 2015-01)Aging is generally accompanied by a progressive loss of skeletal muscle mass and impairments in metabolic function. Even a few days of muscle disuse (such as that occurring during injury or illness) leads to considerable ...
Short-term muscle disuse lowers myofibrillar protein synthesis rates and induces anabolic resistance to protein ingestion Wall, BT; Dirks, ML; Snijders, T; van Dijk, J-W; Fritsch, M; Verdijk, LB; van Loon, LJC (American Physiological Society -, 2016-01-15)Disuse leads to rapid loss of skeletal muscle mass and function. It has been hypothesized that short successive periods of muscle disuse throughout the lifespan play an important role in the development of sarcopenia. The ...
Strategies to maintain skeletal muscle mass in the injured athlete: nutritional considerations and exercise mimetics Wall, BT; Morton, JP; van Loon, LJC (Taylor & Francis (Routledge) for European College of Sport Science, 2014-07)The recovery from many injuries sustained in athletic training or competition often requires an extensive period of limb immobilisation (muscle disuse). Such periods induce skeletal muscle loss and consequent declines in ...