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Divito B, McLaughlin M, Jacobs I. The Effects of L-Citrulline on Blood-Lactate Removal Kinetics Following Maximal-Effort Exercise. J Diet Suppl 2021; 19:704-716. [PMID: 34013839 DOI: 10.1080/19390211.2021.1926392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The accumulation of lactate in muscle and blood during high-intensity exercise is negatively correlated with the duration exercise can be sustained. Removal of lactate is a key component of acute recovery between consecutive bouts of such exercise. Low-intensity exercise enhances recovery by accelerating lactate turnover in metabolically active tissues, largely mediated by blood flow to these tissues. Therefore, the purpose of this research was to clarify if L-citrulline, a nutritional supplement purported to promote vasodilation via enhanced nitric oxide availability, would augment the removal of blood lactate during active recovery (AR). L-citrulline ingestion will augment the rate of blood lactate concentration decrease during AR, reduce the oxygen-cost of submaximal exercise, and increase time-to-exhaustion and peak oxygen uptake (V̇O2peak) during a test of maximal aerobic power. Healthy university students (five males & five females) participated in this double-blind, randomized, placebo-controlled study. Participants exercised on a cycle ergometer at submaximal steady-state intensities followed by progressively increasing intensity to exhaustion, 10 min of AR, and then supramaximal intensity exercise to exhaustion. Oxygen uptake was measured throughout the trial and blood lactate was sampled repeatedly during AR. The protocol elicited very high peak blood lactate concentrations after exercise (11.3 + 1.3 mmol/L). L-citrulline supplementation did not significantly alter blood lactate kinetics during AR, the oxygen cost of exercise, V̇O2peak, or time-to-exhaustion. Despite a strong theoretical basis by which L-citrulline could augment lactate removal from the blood, L-citrulline supplementation showed no effect as an exercise-recovery supplement.
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Affiliation(s)
- Benjamin Divito
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Mackenzie McLaughlin
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Ira Jacobs
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada.,Department of Pharmacology & Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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Shanely RA, Nieman DC, Perkins-Veazie P, Henson DA, Meaney MP, Knab AM, Cialdell-Kam L. Comparison of Watermelon and Carbohydrate Beverage on Exercise-Induced Alterations in Systemic Inflammation, Immune Dysfunction, and Plasma Antioxidant Capacity. Nutrients 2016; 8:nu8080518. [PMID: 27556488 PMCID: PMC4997430 DOI: 10.3390/nu8080518] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/12/2016] [Accepted: 08/18/2016] [Indexed: 02/08/2023] Open
Abstract
Consuming carbohydrate- and antioxidant-rich fruits during exercise as a means of supporting and enhancing both performance and health is of interest to endurance athletes. Watermelon (WM) contains carbohydrate, lycopene, l-citrulline, and l-arginine. WM may support exercise performance, augment antioxidant capacity, and act as a countermeasure to exercise-induced inflammation and innate immune changes. Trained cyclists (n = 20, 48 ± 2 years) participated in a randomized, placebo controlled, crossover study. Subjects completed two 75 km cycling time trials after either 2 weeks ingestion of 980 mL/day WM puree or no treatment. Subjects drank either WM puree containing 0.2 gm/kg carbohydrate or a 6% carbohydrate beverage every 15 min during the time trials. Blood samples were taken pre-study and pre-, post-, 1 h post-exercise. WM ingestion versus no treatment for 2-weeks increased plasma l-citrulline and l-arginine concentrations (p < 0.0125). Exercise performance did not differ between WM puree or carbohydrate beverage trials (p > 0.05), however, the rating of perceived exertion was greater during the WM trial (p > 0.05). WM puree versus carbohydrate beverage resulted in a similar pattern of increase in blood glucose, and greater increases in post-exercise plasma antioxidant capacity, l-citrulline, l-arginine, and total nitrate (all p < 0.05), but without differences in systemic markers of inflammation or innate immune function. Daily WM puree consumption fully supported the energy demands of exercise, and increased post-exercise blood levels of WM nutritional components (l-citrulline and l-arginine), antioxidant capacity, and total nitrate, but without an influence on post-exercise inflammation and changes in innate immune function.
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Affiliation(s)
- R Andrew Shanely
- Human Performance Laboratory, Appalachian State University, North Carolina Research Campus, Kannapolis, NC 28081, USA.
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
| | - David C Nieman
- Human Performance Laboratory, Appalachian State University, North Carolina Research Campus, Kannapolis, NC 28081, USA.
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
| | - Penelope Perkins-Veazie
- Plants for Human Health Institute, North Carolina State University, Department of Horticulture Science, North Carolina Research Campus, 600 Laureate Way, Kannapolis, NC 28081, USA.
| | - Dru A Henson
- Department of Biology, Appalachian State University, Boone, NC 28608, USA.
| | - Mary P Meaney
- Human Performance Laboratory, Appalachian State University, North Carolina Research Campus, Kannapolis, NC 28081, USA.
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
| | - Amy M Knab
- Kinesiology Department, Queens University of Charlotte, Charlotte, NC 28274, USA.
| | - Lynn Cialdell-Kam
- Department of Nutrition, Case Western Reserve University, Cleveland, OH 44106, USA.
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