The graph represents the effect of increased stress on the performance of the body. The lower the stress levels are in the body, the less likely the allostatic load model will have a significant effect on the brain and health. Although, an increase in stress levels results in an increase in stress on the brain and the health of individuals, making it more likely for the body to have significant effects on homeostasis and cause breakdown of the body systems.
Allostatic load is "the wear and tear on the body" which accumulates as an individual is exposed to repeated or chronic stress. The term was coined by Bruce McEwen and Eliot Stellar in 1993. It represents the physiological consequences of chronic exposure to fluctuating or heightened neural or neuroendocrineresponse which results from repeated or prolonged chronic stress.