While more research certainly needs to be done - the hard evidence is lacking at current - Dr. Michael Barnish, Head of Genetics and Nutrition at REVIVD, points out that the Scandinavians have been practising cold water therapy for centuries, alongside many countries with colder climates, like Chile and Canada. "They utilise the wild open waters over their shower or spa."
The main reason the research is lacking, he shares, is that cold water is often free. Dr Barnish explains that when looking at cold water therapy for a particular symptom or disease management, the funding is usually hard to come by, as there is little profit to be had.