General Adaptation Syndrome
Posted: Tue Jul 15, 2003 3:01 pm
From a physilogical standpoint the concept of periodization is based on a concept of Selye's Adaptation Syndrome can you discuss the GAS.
Clinic notes presented by Michael H. Stone, who is an internationally known expert in resistance training.
General Adaptation Syndrome (GAS):
Han's Selye was a physiologist interested in why humans age and die. He believed that accumulative stress was related to the aging process and based on this premise developed the "General Adaptation Syndrome" (GAS) in the late 1920's and early 1930's.
The GAS describes a person's changing ability to adapt to stress through a lifetime. Briefly, Selye believed that humans exhibited a common response to most stressful situations regardless of their nature (i.e. physical, environmental, emotional). These responses include increased cortisol and catecholamine concentrations, and increase heart rate and blood pressure. The stimuli causing these responses were considered "stressors". Various stressors are encountered from birth to death and each cases a stress response which includes various phases.
The first phase of the response is the alarm phase in which there is an initial disturbance in homeostasis. The second stage is the resistance phase in which adaptation is made and the organism is able to withstand the stressor. A third stage is also possible. If the stressor or accumulative stressors are so strong that resistance is not possible then the exhaustion phase is reached and illness or even death results.
Selye believed that the aging process could be partly explained by the result of accumulative stressors over a lifetime. The accumulation of stressors reduces the ability to resist stressors and will eventually result in an exhaustion stage resulting in death.
Although, it is presently known that GAS does not explain all responses and adaptations to stressors it can serve as a useful model to help explain responses and adaptations to exercise and training.