New research finds a short cold plunge between sauna rounds eases heat strain.

New research from Bangor University has found that adding a brief cold water dip to a sauna cooling break meaningfully reduces the strain that heat puts on the body, even when the dip is short and the water isn't especially cold.

The study was carried out in partnership with Sawna Bach in Llanberis, and is the first published research to come out of this growing collaboration. The British Sauna Society has also pledged its support for the ongoing research.

What the study looked at.

Sixteen volunteers each did two 15-minute sauna sessions, with a 10-minute break in between to cool down. On one visit, they cooled down by sitting in the fresh air. On another, they did the same, but added a 90-second dip in water at around 20°C, which is mild by cold water immersion standards and closer to a summer lake than an ice bath.

Comparing the two showed a clear pattern: adding the cold dip noticeably reduced how much participants' heart rate and body temperature rose during the second sauna session, and how hot and strained they felt by the end of it. Their body temperature and sweat levels also returned to normal faster afterwards.

Why it matters.

Sauna works by placing a healthy stress on the body's cardiovascular systems, which is part of what makes it beneficial. But without adequate cooling between rounds, that strain can build up, leaving bathers overheated, uncomfortable, or at greater risk of feeling faint. This research suggests that a short, manageable cold dip between rounds is a simple and effective way to ease that strain, making sauna sessions both safer and more comfortable - something particularly worth knowing for those newer to sauna, or less used to heat.

The findings reflect what sauna cultures have long done instinctively, pairing heat with cold water immersion to have a real, measurable effect on how the body copes with sauna.

Read the full paper, published in Experimental Physiology:
doi.org/10.1113/EP093626