Regional blood-flow changes during 72-hour avoidance schedules in the monkey.

Systemic and regional blood-flow measurements were made in five restrained monkeys before and during 72 hours of continuous work on an avoidance schedule. Systemic arterial pressures were elevated throughout the stress, initially owing to an increase in cardiac output, and after 72 hours owing to an increase in total peripheral resistance. Changes in the resistance in skeletal muscle blood vessels were closely related to these changes in total peripheral resistance.