Cold plunge has long been known to have health benefits. Want to take a plunge locally? The Porchester Spa in Bayswater, often referred to as the oldest spa in London, has had a recent £800,000 refurbishment, upgrading its facilities while also keeping the Grade II-listed building true to its 1920s roots. They have steam rooms, Turkish baths, a sauna, plunge pool, relaxation lounge, treatment rooms, and café. Check the entrance schedule before you visit as Sunday is the only mixed male/female spa day.