The Effects of Caffeine on Well-Being at People Over 50 Years: Direct Effect or Mediated Via Physical Activity, Anxiety, and Depression?

Background: Caffeine's influence on numerous physical functions indicates that it has more than a simple stimulating effect. The aim of this study is to investigate the effects of caffeine on well-being, taking into account physical activity, anxiety, and depression as mediators. Materials and Methods: A sample of 160 subjects 50 years of age and older were recruited for this study. Five standardized questionnaires and an extension of the simple mediatized regression with three mediators made it possible to check the model relationships. Research was conducted in accordance with the 2013 revised Declaration of Helsinki. Results: The results could demonstrate no indirect effect through one or a combination of the mediator variables, but a direct effect of caffeine on well-being (p = 0.01, β = 0.16), provided that the three variables were taken into account. Conclusion: Due to the fact that individual compounds, and especially, the direct effect of caffeine on well-being in this model, were found to be significant, these findings could be the foundation for future research.