Momentary physical activity, subjective age, and the moderating role of pain.

Subjective age, that is felt age compared to chronological age, is an important predictor of health and well-being in later life. It can fluctuate from day to day and from one moment to another. Previous cross-sectional and macro-longitudinal studies have shown that feeling younger is related to physical fitness and exercise. Yet, there is limited knowledge on the effects of physical activity on subjective age in daily life and moderators of this association. We thus aim to investigate the association of momentary physical activity with momentary subjective age, expecting that more activity is related to feeling younger. We further expect that concurrent pain experience attenuates this relationship. N = 54 participants aged 50-62 years (Mage = 56.1 years, 75% female) wore chest-sensors measuring their physical activity (step count, movement acceleration) for one week and reported on their subjective age five times per day. Multilevel regression analyses revealed between and within-person variation in momentary subjective age (ICC = 0.74), pain (ICC = 0.63) and physical activity (ICC Moac30 = 0.078, steps30 = 0.053). Pain emerged as a consistent predictor of momentary subjective age (b = 4.64, p = 0.000), whereas results were mixed for the physical activity measures. No significant moderating effect of pain was observed on the relationship between physical activity and subjective age. Our study shows the importance of pain experiences for momentary subjective age, whereas the role of momentary physical activity needs further exploration.