Characterization of Dynamic Adaptation to Stressors Using Multisystem Stimulus-Response Data: The Study of Physical...

Area of Science:

• Gerontology and Physiology
• Stress Response Mechanisms
• Aging Research

Background:

• Resilience is a key gerontological concept for positive aging outcomes.
• Understanding the physiological mechanisms of resilience is crucial.
• Physical resilience may be rooted in the body's stress response system.

Purpose of the Study:

• To test the hypothesis that physical resilience is linked to physiological fitness.
• To characterize physiological fitness in older adults facing major stressors.
• To investigate adaptation capacity using stimulus-response physiological measures.

Main Methods:

• The Study of Physical Resilience in Aging (SPRING) pilot study (n=79).
• Analysis of heart rate variability (HRV) via Holter monitoring.
• Assessment of cortisol responses to adrenocorticotropic hormone (ACTH) stimulation and diurnal salivary cortisol.
• Principal component analysis to identify steady-state and adaptation mechanisms.

Main Results:

• Physiological measures demonstrated underlying adaptation mechanisms, supporting construct validity.
• Component scores varied significantly based on stressor type and surrogate physiological measures, evidencing criterion validity.
• Combined HRV, ACTH, and salivary cortisol data effectively assessed adaptation capacity across diverse stressors.

Conclusions:

• The SPRING study provides proof of principle for physiological fitness underlying physical resilience.
• This is the first human study to concurrently assess multiple physiological systems via stimulus-response tests.
• Findings support future validation for forecasting older adults' resilience to clinical stressors.