Why Hot and Cold Feels So Good

There's a particular look people have after a sauna and cold plunge. A bit dazed. A bit smiley.

At Glasgow Community Sauna, the hot-cold routine is pretty simple. Warm up in the sauna, cool down in the plunge, rest for a bit, then go again if you fancy it.

Simple. A bit dramatic. Very satisfying.

What happens in the sauna?

In the sauna, your body responds to the heat. Your skin warms up, your heart rate rises and you start to sweat.

Lots of people find it relaxing. Muscles can feel looser, you sit still for a while, and there's not a huge amount to do except talk to whoever's beside you or stare into the middle distance.

It can feel particularly good if you've arrived with your shoulders somewhere near your ears.

Sauna isn't a magic cure for everything though. It's heat, and your body is working hard to deal with that heat, so it can get overwhelming for some people. Drink water, take breaks and get out if you feel dizzy, uncomfortable, or simply done.

You don't get extra points for staying in longer.

What happens in the cold plunge?

Cold water is a very different situation.

When you first get in, the sudden drop in skin temperature can trigger what's known as the cold-shock response. You might gasp, your breathing can speed up, and your heart rate and blood pressure can rise. It's one of the reasons to get in carefully rather than launching yourself straight into it. (PubMed)

You'll also become extremely aware of being alive! Some people come out feeling alert, clear-headed or calm. Others mainly enjoy the bit afterwards, wrapped in a towel and looking quietly victorious. Both are fair.

If it's your first time, there's no need to stay in for ages. Get in, see how you respond and get back out when you've had enough.

Why do people call it ‘contrast therapy?

Contrast therapy generally means alternating between heat and cold. At GCS, that might mean sauna, cold plunge, a rest, then another round.

The contrast is a big part of why people enjoy it. You're properly warm, then very suddenly you're not. Afterwards, you sit down and let everything settle before deciding whether another round sounds appealing.

You can make this as complicated as you like online. There are protocols, timers, optimal temperatures and people who look suspiciously happy about being uncomfortable.

We prefer the simpler version - pay attention to how you feel. Take your time. Don't turn it into a competition. Noone needs to become a motivational poster in the plunge pool.

What are the possible benefits?

This is where it's worth being a bit careful.

There's quite a lot of research into sauna and passive heat exposure, including studies looking at cardiovascular health. Some long-term observational studies have found links between frequent sauna use and better cardiovascular outcomes, but that doesn't necessarily mean sauna caused those outcomes.

When researchers have looked specifically at controlled trials of passive heating, the results have been less clear. A 2025 systematic review found no significant overall improvement across most cardiometabolic and vascular measures, although there was some evidence of a possible reduction in systolic blood pressure in certain groups. The researchers said that finding should be interpreted cautiously. (PubMed)

The evidence around cold-water immersion is still developing too.

A 2025 systematic review found some potentially interesting effects relating to stress, sleep, inflammation and quality of life, but the researchers also pointed out that there are relatively few good-quality trials, sample sizes tend to be small and the people studied aren't particularly diverse. (PubMed)

So we're not going to tell you that jumping between hot and cold will fix your immune system, cure your anxiety or add twelve years to your life.

Plenty of people simply feel good afterwards. Calmer, more awake, physically relaxed, or just quite pleased with themselves for getting into the cold water.

That's reason enough to enjoy it. We don't need to turn it into medicine.

How to try sauna and cold plunge without overdoing it

Start gently.

You don't need to stay in the sauna for as long as possible, and you definitely don't need to sit in the plunge waiting for your ancestors to appear.

Have some time in the sauna. When you've had enough, come out and cool down. If you fancy the plunge, get in carefully and see how it feels.

Then rest.

That bit is easy to skip when you're excited about doing another round, but sitting around between hot and cold is part of the whole thing.

Drink water. Give yourself time. If you start feeling dizzy, lightheaded, unwell or uncomfortable, stop.

If your body says, that's enough heat for now pal, believe it.

Who should be cautious?

Sauna and cold plunging aren't suitable for everyone, and sudden changes in temperature put extra demands on the cardiovascular system.

If you have a heart or cardiovascular condition, problems with high or low blood pressure, a history of fainting, or take medication that affects blood pressure, circulation or temperature regulation, speak to a GP or relevant healthcare professional before using a sauna or cold plunge.

The same applies if you have another medical condition that could be affected by heat, cold or rapid changes in temperature.

If you're pregnant, the evidence around sauna use during pregnancy is limited. NHS guidance notes the risks of overheating, dehydration and fainting and says pregnant people may choose to avoid saunas, hot tubs and similar environments. Speak to your midwife or GP if you're unsure. (Collingwood Surgery)

Don't use the sauna or cold plunge if you're feeling unwell.

And don't sauna after drinking alcohol. Save it for another day.

On the day itself, listen to your body. No session is improved by pretending you're fine when you're not.

Sauna and cold plunge in Glasgow

For some people, sauna and cold plunge becomes a weekly thing. After work. Before the weekend. On a Sunday. Whenever your brain has too many tabs open and none of them are useful.

For others, they might love the sauna, but the cold plunge remains something they'll stare at suspiciously three times before finally getting in. And that's also fine.

You don't need a protocol and you don't need to be good at it. Come down, get warm, try the cold if you want to, sit about for a bit and see how you feel.

If you're curious about sauna and cold plunge in Glasgow, have a look at our upcoming sessions at Glasgow Community Sauna.

Bring a towel. Bring a water bottle. Take it at your own pace.