Tyrosine supplementation does not influence the capacity to perform prolonged exercise in a warm environment
Abstract
Eight young men were recruited to a study designed to examine the effect of tyrosine (TYR) supplementation on the capacity to perform prolonged exercise in a warm environment. Subjects entered the laboratory in the morning and remained seated for 1 hr before cycling to exhaustion at 70% VO2peak. Two 250-ml aliquots of a placebo (PLA ) or a TYR solution were ingested at 30-min intervals before exercise, with an additional 150 ml consumed every 15 min throughout exercise (total TYR dose: 150 mg/kg BM). Cognitive function was assessed before drink ingestion, at the end of the rest period, and at exhaustion. TYR ingestion had no effect on exercise capacity (PLA 61.4 ± 13.7 min, TYR 60.2 ± 15.4 min; p = .505). No differences in heart rate (p = .380), core temperature (p = .554), or weighted mean skin temperature (p = .167) were apparent between trials. Ingestion of TYR produced a marked increase in serum TYR concentrations (+236 ± 46 μmol/L; p < .001), with this difference maintained throughout exercise. No change was apparent during the PLA trial (p = .924). Exercise caused an increase in error rate during the complex component of the Stroop test (p = .034), but this response was not influenced by the drink ingested. No other component of cognitive function was altered by the protocol (all p > .05). Ingestion of a TYR solution did not influence time to exhaustion or several aspects of cognitive function when exercise was undertaken in a warm environment.
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All seven studies that measured plasma tyrosine levels found significantly elevated levels after tyrosine intake compared to placebo.
“All seven studies in which plasma tyrosine levels were measured (Strüder et al., 1998;Sutton et al., 2005;Shurtleff et al., 1994;Chinevere et al., 2002;Tumilty et al., 2011Tumilty et al., , 2014;;Watson et al., 2012) found these levels to be significantly elevated after tyrosine intake compared to placebo.”
From Behavioral and cognitive effects of tyrosine intake in healthy human adults (2015) · cites this paper as Watson et al., 2012
Among six studies of endurance exercise performance in physically trained young men, five found no significant difference between tyrosine and placebo, while one found tyrosine enhanced performance.
“While one study found tyrosine to enhance endurance exercise performance (Tumilty et al., 2011), five studies found no significant differences between tyrosine and the placebo (Strüder et al., 1998;Sutton et al., 2005;Chinevere et al., 2002;Tumilty et al., 2014;Watson et al., 2012).”
From Behavioral and cognitive effects of tyrosine intake in healthy human adults (2015) · cites this paper as Watson et al., 2012
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Cognitive Performance after Strenuous Physical Exercise
Hogervorst, E., Riedel, W., Jeukendrup, A., & Jolles, J. (1996) · Perceptual and Motor Skills · doi:10.2466/pms.1996.83.2.479 · Cited by 244 · see citing works
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Clark, A., & Mach, N. (2016) · Journal of the International Society of Sports Nutrition · doi:10.1186/s12970-016-0155-6 · Cited by 583 · see citing works
“However, tyrosine ingestion does not influence time to exhaustion or several aspects of cognitive function while exercising in heat conditions [128].”
BackgroundJongkees, B. J., Hommel, B., Kühn, S., & Colzato, L. S. (2015) · Journal of Psychiatric Research · doi:10.1016/j.jpsychires.2015.08.014 · Cited by 177 · see citing works
Behavioral and cognitive effects of tyrosine intake in healthy human adults
Hase, A., Jung, S. E., & aan het Rot, M. (2015) · Pharmacology Biochemistry and Behavior · doi:10.1016/j.pbb.2015.03.008 · Cited by 91 · see citing works
Failure of oral tyrosine supplementation to improve exercise performance in the heat
TUMILTY, L., DAVISON, G., BECKMANN, M., & THATCHER, R. (2014) · Medicine & Science in Sports & Exercise · doi:10.1249/mss.0000000000000243 · Cited by 30 · see citing works
- Authors
- Watson, P., Enever, S., Page, A., Stockwell, J., & Maughan, R. J.
- Affiliations
- Loughborough University (GB)
- Venue
- International Journal of Sport Nutrition and Exercise Metabolism
- Publisher
- Human Kinetics
- Published
- 2012-10
- Volume
- 22
- Issue
- 5
- Pages
- 363-373
- ISSN
- 1526-484X (ISSN-L)
- 1543-2742
- OpenAlex
- W16709030
- Cited by
- 40
- References
- 1
- Citations by year
- 2026: 1 · 2025: 3 · 2024: 3 · 2023: 2 · 2022: 2 · 2021: 1 · 2020: 3 · 2019: 1 · 2018: 2 · 2017: 4 · 2016: 3 · 2015: 6 · 2014: 6 · 2013: 3
- FWCI
- 3.22
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- International Journal of Sport Nutrition and Exercise Metabolism (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Physiology › Thermoregulation and physiological responses
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
- Health Sciences › Medicine › Rehabilitation › Exercise and Physiological Responses
- Keywords
- tyrosine supplementation, prolonged exercise, heat stress, time to exhaustion, cognitive function, Stroop task, serum tyrosine, core body temperature, heart rate
- MeSH terms
- Hot Temperature, Humans, Skin Temperature, Tyrosine, Exercise, Exercise Tolerance
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