Contrast therapy: does alternating hot and cold actually work?
Does contrast therapy work? What research shows on alternating hot and cold for recovery, soreness and metabolism, plus the heart risks founders should know.
A Cinder series
The Recovery Lab
An evidence-first look at sauna, cold plunges, float tanks, red light, PEMF, hyperbaric oxygen and sleep tech: what works, what's hype, and what's worth your time.
Cold plunge benefits: what the evidence behind the ice bath shows
Cold plunge benefits, checked against the research: what a 2025 meta-analysis found on stress, sleep and sick days, plus the cold shock and heart risks.
Sauna benefits: what the Finnish studies actually found
Sauna benefits, checked against the Finnish research: what the 2015 JAMA Internal Medicine study found on heart health and mortality, and what it can't prove.