Effects of altitude acclimatization on rat myoglobin. Changes in myoglobin content of skeletal and cardiac muscle

Abstract

Analyses were made of myoglobin content of rat skeletal and cardiac muscle following continuous exposure to simulated altitudes of 18,000 feet for a 2–10-week period. About five dozen rats were used. Acclimatization was associated with an increase in the myoglobin concentration of thigh, diaphragm, gastrocnemius and heart muscles. Total myoglobin content, however, increased during acclimatization in cardiac muscle but not in the three skeletal muscles. This finding together with the body weight changes and muscle weight changes suggested that the increases in myoglobin concentration of skeletal muscle may be merely a reflection of a decreased water content of muscles.