Composition of sweat of the horse during prolonged epinephrine (adrenaline) infusion, heat exposure, and exercise

Am J Vet Res. 1983 Aug;44(8):1571-7.


Temporal changes in sweat composition were studied in 4 horses during epinephrine (adrenaline) infusion (0.13 to 0.31 micrograms/kg/min for 3 hours), heat exposure (41 C, [33 C wet bulb] for 5 to 6 hours), and exercise (16 to 18 km/hr for 58 to 80 km). Four ponies also were studied during heat exposure. Sweat produced by each of the stimuli was hypertonic for Na+, K+, and Cl-. These electrolyte concentrations remained constant during the central period of the experiments, with changes occurring near the beginning and toward the end. The Na+ was significantly higher and K+ significantly lower in epinephrine-induced sweat than in heat-induced sweat, and the pattern of change in sweat Na/K ratio varied among the 3 stimuli. The Ca2+ concentration decreased with time and was hypotonic after 15 minutes of epinephrine-induced sweating. Concentrations of Mg2+ and protein decreased exponentially with time. There was a high correlation between them, although the Mg2+ was not protein-bound. Sweat urea concentration was directly related to plasma urea concentration. When plasma glucose concentration became greater than 10 to 12 mmole/L during epinephrine infusion, glucose appeared in the sweat and its concentration rose to 8 to 12 mmole/L of sweat when plasma glucose was more than 20 mmole/L.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / analysis
  • Chlorides / analysis
  • Epinephrine / pharmacology*
  • Glucose / analysis
  • Horses / metabolism*
  • Hot Temperature*
  • Hydrogen-Ion Concentration
  • Magnesium / analysis
  • Physical Exertion*
  • Potassium / analysis
  • Proteins / analysis
  • Sodium / analysis
  • Sweat / analysis*
  • Sweat / drug effects
  • Sweating / drug effects
  • Urea / analysis


  • Chlorides
  • Proteins
  • Urea
  • Sodium
  • Magnesium
  • Glucose
  • Potassium
  • Calcium
  • Epinephrine