Dietary tyrosine benefits cognitive and psychomotor performance during body cooling

Physiol Behav. 2007 Feb 28;90(2-3):301-7. doi: 10.1016/j.physbeh.2006.09.027. Epub 2006 Oct 31.


Supplemental tyrosine is effective at limiting cold-induced decreases in working memory, presumably by augmenting brain catecholamine levels, since tyrosine is a precursor for catecholamine synthesis. The effectiveness of tyrosine for preventing cold-induced decreases in physical performance has not been examined. This study evaluated the effect of tyrosine supplementation on cognitive, psychomotor, and physical performance following a cold water immersion protocol that lowered body core temperature. Fifteen subjects completed a control trial (CON) in warm (35 degrees C) water and two cold water trials, each spaced a week apart. Subjects ingested an energy bar during each trial; on one cold trial (TYR) the bar contained tyrosine (300 mg/kg body weight), and on the other cold trial (PLB) and on CON the bar contained no tyrosine. Following each water immersion, subjects completed a battery of performance tasks in a cold air (10 degrees C) chamber. Core temperature was lower (p=0.0001) on PLB and TYR (both 35.5+/-0.6 degrees C) than CON (37.1+/-0.3 degrees C). On PLB, performance on a Match-to-Sample task decreased 18% (p=0.02) and marksmanship performance decreased 14% (p=0.002), compared to CON, but there was no difference between TYR and CON. Step test performance decreased by 11% (p=0.0001) on both cold trials, compared to CON. These data support previous findings that dietary tyrosine supplementation is effective for mitigating cold-induced cognitive performance such as working memory, even with reduced core temperature, and extends those findings to include the psychomotor task of marksmanship.

Publication types

  • Controlled Clinical Trial
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptation, Physiological
  • Adolescent
  • Adult
  • Body Temperature / drug effects*
  • Body Temperature / physiology
  • Cognition / drug effects*
  • Cognition / physiology
  • Cold Temperature
  • Dietary Supplements
  • Discrimination Learning / drug effects*
  • Discrimination Learning / physiology
  • Female
  • Humans
  • Male
  • Memory, Short-Term / drug effects
  • Memory, Short-Term / physiology
  • Psychomotor Performance / drug effects*
  • Psychomotor Performance / physiology
  • Reference Values
  • Statistics, Nonparametric
  • Tyrosine / administration & dosage
  • Tyrosine / pharmacology*


  • Tyrosine