Muscles..

 

  When skeletal muscles contract during resistance training, they act as an endocrine organ, secreting small proteins called myokines. These molecules cross the blood-brain barrier to trigger neurogenesis, reduce systemic inflammation, and naturally boost resilience against environmental stress.  

 Regular muscle-strengthening activities stimulate the brain to produce and balance mood-regulating chemicals like serotonin, dopamine, and endorphins. This mechanism closely mimics the positive chemical shifts targeted by traditional antidepressant medications.  

 A landmark clinical meta-analysis published in JAMA Psychiatry proved that lifting weights two or more days a week drastically cuts symptoms of depression and anxiety. 

Crucially, participants experienced these psychological lifts regardless of how much physical muscle strength they actually gained, proving that the intentional act of pushing against resistance alters emotional states.  Just a thought.