Tyrosine Supplementation Does Not Influence the Capacity to Perform Prolonged Exercise in a Warm Environment

Click name to view affiliation

Phillip Watson
Search for other papers by Phillip Watson in
Current site
Google Scholar
PubMed
Close
,
Sophie Enever
Search for other papers by Sophie Enever in
Current site
Google Scholar
PubMed
Close
,
Andrew Page
Search for other papers by Andrew Page in
Current site
Google Scholar
PubMed
Close
,
Jenna Stockwell
Search for other papers by Jenna Stockwell in
Current site
Google Scholar
PubMed
Close
, and
Ronald J. Maughan
Search for other papers by Ronald J. Maughan in
Current site
Google Scholar
PubMed
Close
Restricted access

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.

The authors are with the School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire, UK.

  • Collapse
  • Expand