LYZ and major depressive disorder: The pre/post assessment included: (1) salivary anti-microbial proteins lysozyme; (Lys) and immunoglobulin-A (IgA); (2) salivary steroid hormones of testosterone (TT) and cortisol (COR); (3) functional fitness (gait speed, hand grip strength, and static balance); (4) MWB questionnaires (happiness, depression state, satisfaction with life, and stress).