**Figure 8.** **Resilience and its age-related degradation can be measured using longitudinal motion sensor data.** (**A**) The relaxation rate (or the inverse characteristic recovery time) computed for sequential age-matched cohorts of Fitbit users decreased approximately linearly with age. The recovery rate could be extrapolated to zero in the age exceeding ~110 y.o. (at this point, we may expect the complete loss of resilience and, hence, loss of stability of the organism state). The shaded area shows the 95% confidence interval of fit using GeroSense BAA. (**B**) The fraction of individuals suffering from the lack of resilience (defined as BAA’s autocorrelation time exceeding 3 weeks; the vertical axis) as the function of chronological age (the horizontal axis). The autocorrelation time was computed from longitudinal tracks of GeroSense BAA predicted for Fitbit wristband users.