cold plunge - 3 months in, honest review from a skeptic

started skeptical. did it 4-5x/wk for 90 days. what i notice: mood lift for ~3-4 hrs after, better cold tolerance (duh), subjectively better focus mornings i plunge. no measurable impact on sleep, HRV, resting HR over 90 days. worth doing for the mood bump, not worth the $$ fancy tub - my bathtub + ice works. not a cure for anything. a tool.