Luke O'Neill

There is cardiovascular effects as well.

And, of course, for thousands of years, us humans have got into hot rooms or hot places called sweat houses.

The Romans did it, the Greeks, of course.

Even the Irish, the Celts had these, literally, they were called sweat houses.

They would, you know, heat up rocks and just like a sauna, really.

So it seems to be a common thing that we've ever done.

I mean, what they think is happening there, by the way, is, again, we evolved.

And remember, if you're a biologist...

you see everything through the lens of evolution to explain everything.

And you can explain everything in biology, most things anyway.

So we evolved in Africa, what, 300,000 years ago, Homo sapiens begins to emerge.

It was very hot there and we liked it.

That was our optimum environment, if you like.

When we got cleverer,

and began to realise we could wear clothes or light fires, we move into colder places.

We remember the heat and we want it back, you know.

So one reason we like all this is probably because we evolved in an environment that was hot and steamy anyway.

And so therefore we want to go back to that kind of, maybe subconsciously, who knows.

So maybe it's something to do with the fact that we evolved in warm, humid places and now we're in a cold place and we long,

for that heat yet again.