Skip to main content

Physiological Flexibility Index

Meaning

The Physiological Flexibility Index is a composite metric that quantifies an organism’s capacity to rapidly and efficiently adapt its internal physiological parameters in response to changing internal or external environmental demands. This index integrates multiple dynamic measures, such as heart rate variability (HRV), metabolic switching capacity (e.g., between glucose and fat utilization), and the speed of recovery from acute stress. A high index indicates robust allostatic capacity, meaning the body can quickly return to a state of homeostasis after perturbation, which is a key characteristic of health and biological youth. It serves as a measure of systemic resilience.