The effects of physical fitness and feeling vigorous on self-rated health.

OBJECTIVE: We prospectively studied the hypothesized beneficial effects of feeling vigorous and of objective physical fitness (gauged based on functional capacity) on subsequently assessed self-rated health (SRH), controlling for possible confounders known to be precursors of SRH and of our predictors. We also investigated the reverse-causation hypothesis that SRH predicts subsequent vigor and functional capacity. DESIGN: Participants were apparently healthy employees (N = 779) who underwent a routine health check at two points of time, Time 1 (T1) and Time 2 (T2), about 18 months apart. We used regression analysis, predicting T2 SRH by T1 SRH, the control variables, and T1vigor and functional capacity. MAIN OUTCOME MEASURES: Vigor was assessed using the Shirom-Melamed Vigor Measure; objective physical fitness was indicated by functional capacity following a treadmill exercise, and self-rated health was measured by a single item. RESULTS: As hypothesized, we found that the change in T2 SRH was positively predicted by T1 vigor, functional capacity, and their interactive term. Testing the reverse causation paths, we found that T1 SRH did not predict subsequent functional capacity and was a relatively weak predictor of subsequent vigor. CONCLUSION: The affective state of vigor and objectively assessed functional capacity interact to predict subsequent changes in self-rated health.