Skin barrier
The outermost layer of skin that keeps moisture in and irritants out.
Progressive overload
Gradually increasing training demand — weight, reps, or difficulty — over time.
Cortisol
Your primary stress hormone, involved in energy, alertness, and inflammation.
Collagen
The most abundant protein in your body — structure for skin, joints, and connective tissue.
Circadian rhythm
Your internal 24-hour clock that regulates sleep, hormones, digestion, and energy.
Definitions are general education, not medical advice. The glossary grows with the site — entries are managed under Knowledge Base in the WordPress admin.