Measure your own reserve
The Functional Reserve Index is a free set of six simple self-tests: grip, two chair-stand tests, walking speed, balance, and an aerobic fitness estimate. Each result is measured against fixed published lines that do not move with age. Repeat the tests every few months, with any help written down, and the site shows whether your margin is holding. No account, and your results stay on your device.
Take the self-tests
reserve.theaskingpress.com · For education only, not medical advice.
The research
PublishedO’Leary RT. The Preservation of Functional Reserve: A Control Systems Framework for Human Aging. Life. 2026;16(9):1457. doi:10.3390/life16091457
O’Leary RT. Short-Horizon Metrics and the Persistence of Capacity-Debiting Practices in Nursing Homes. Preprints.org, 2026. Preprint. doi:10.20944/preprints202610.1146.v1
O’Leary RT. Weaker, Not Just Lighter: Monitoring Strength and Function, Not Lean Mass, During GLP-1 Weight Loss. Preprints.org, 2026. Preprint. doi:10.20944/preprints202610.0108.v1
O’Leary RT. Assistance State as a Condition of Functional Measurement: Distinguishing Assisted Performance from Performance at a Lower Assistance State. Preprints.org, 2026. Preprint. doi:10.20944/preprints202609.2065.v2
O’Leary RT. The Reserve Protocol: A Measurement Specification for Functional Reserve. Preprints.org, 2026. Preprint. doi:10.20944/preprints202609.1685.v1
O’Leary RT. Is Immune Homeostatic Competence a Distinct Capacity? A Falsifiable Test for a Sixth Determinant of Functional Reserve. Zenodo, 2026. Preprint. doi:10.5281/zenodo.22728017
O’Leary RT. New Horizons in Reserve Variability: Point, Slope, and the Third Axis of Serial Functional Measurement. Preprints.org, 2026. Preprint. doi:10.20944/preprints202609.0581.v1
O’Leary RT. The Governing Minimum: Multi-Domain Rate Asymmetry Under Challenge as Functional Reserve. Preprints.org, 2026. Preprint. doi:10.20944/preprints202609.0084.v2
O’Leary RT. Unrecorded Load Exceeds the Reference Change Value: Condition of Measurement in GDF15 Research. Preprints.org, 2026. Preprint. doi:10.20944/preprints202608.0304.v1
O’Leary RT. The Gain–Loss Ratio: Defining a Missing Quantity in Human Capacity Dynamics. SportRxiv, 2026. Preprint. doi:10.51224/SportRxiv.1029