Ask a Pro: Haley Smith and the science of saunas

Maybe it’s the extra cold weather this winter or maybe it’s just my sore, aging body, but I’ve been noticing a lot more athletes incorporating saunas into their training lately. And not, as far as I can tell, for the head adaptation effect that I’d expect.

One of these athletes is Haley Smith. The Ontario Olympian, recent Life Time Grand Prix winner (2022) and, now, Trek Driftless racer and her partner Andrew L’Esperance are sauna regulars, won over by the science backing incorporating a post-workout sweat into their training program. There are many uses for saunas, like heat acclimation, stress relief and, as one friend with a DIY backyard kit said, its just nice to use. Smith, as a professional athlete, is looking for a more focused effect on altitude or heat, depending on the race, and inflammation. We caught up with the Canadian over the phone to find out more about the science behind saunas.

Canadian MTB: So there are lots of different recovery modalities out there. What put you onto sauna use? Was it an outcome you were looking for? A problem you were trying to find a solution to? Or just a newer modality that looked interesting? 

Haley Smith: First of all, a lot of the recovery modalities out there don’t actually have a ton of science that can definitively say they do something. For saunas, the science actually is pretty definitive. There is a lot of actual evidence of the ways saunas have an impact, compared to stretching or foam rolling or Normatec boots, where the science isn’t as clear. 

The second part is that we were looking for two specific outcomes. The first was actually a training adaptation not recovery. We’re using it for simulated altitude. The second aspect is for helping with inflammation. 

I think some people would be surprised to hear saunas being used for altitude and inflammation instead of, say, heat adaptation. Is this newer? Or a different outcome of the same physiological effect? 

It’s a pretty similar method of use and honestly a pretty similar adaptation to what you’re after when you’re doing heat training. But it is a little bit of a different, or a more targeted outcome that you’re after. We have used it for heat training in the past and it’s a very similar protocol to when you use it for altitude.

The heat adaptation process is pretty much maxed out after 14 days. The benefits you get for heat training from the sauna are primarily to do with sweat rate and plasma volume and, to some extent, concentration. And ventilation rate. Those things also help you at altitude. That provides you with some of the foundational benefits you would get in the early days of an altitude exposure. But there’s evidence to show that if you continue to use the sauna beyond that two weeks you do start to see changes in red blood cell count as well. Plasma volume will increase first, then you’ll get the stimulus to increase red cell concentration also.

So it’s a relatively good proxy for altitude if you can’t go to altitude to train or if you’re looking to maintain some of the benefits you got from an altitude camp. But the long answer to your question is that it’s the same protocol you’d use for heat training and with similar benefits just with a different way of looking at the long term protocol. 

With a busy race schedule, you Andrew are both away from home a lot. Is this something you try continue and replicate on the road? Or is it something you plan a training period around when you’re at home? Or something you do during specific training blocks?

It’s just something we do in specific training blocks, if we’re specifically looking for a heat or altitude adaptation. So for example this year, prior to Leadville, we have time to do an altitude block, it just didn’t work. I did do an altitude camp significantly earlier in the year and then just relied on the sauna to prepare for Leadville. L’Espy did no altitude all summer before Leadville and just used the sauna.

In season, when It’s not feasible to be away from home, whether financially or with our schedule, we’ll use it to prepare for an altitude race. Then, throughout the season, we use it more intermittently to help with inflammation reduction, and to keep up sweat volume or sweat rate as a sort of top up.

That’s cool that it can open up altitude training to people who can’t, for various reasons, take off to the mountains. 

Yea. I, personally, don’t think there’s anything as good as just going to altitude but there’s only one place in Canada, really, where you can live above 1,600m. And that’s just not feasible. With three altitude camps, you could buy a sauna that you can have for your whole life. It’s an upfront investment, but if you’re going to use it for multiple years and you enjoy it, I think it’s worth it. It’s not easy to uproot your life for at least three weeks and go live somewhere at altitude. 

Are you following a specific training protocol that is weeks-long, which it sounds like you are, or is this something that you – or others – could get some benefit from doing in and around your daily life?

You can definitely get the benefit but, like anything, if you optimize you’re going to see a greater benefit. So, the way that we use it when we’re doing altitude prep is we’d try to do five to six days in a row for three weeks at a time. We’re protecting our rest day, not adding too much stress. But if we’re feeling pretty recovered we might continue on for that seventh day. But you basically just use it immediately after training when you’re slightly dehydrated and your core temperature is already elevated. There’s a specific temperature – we try to run it between 70 and 90-degrees Celsius, which is really hot – and we work up to 30 minutes. But we start at a much lower exposure time, probably starting at 10-15 minutes and working up a little bit each day. Yeah, that’s the bones of the protocol. 

You’re supported by Backcountry Recreation. Was there anything that stood out about that sauna?

Yeah, we wanted a barrel. We think they look really nice and there’s a lot of history and specific science done on Finnish saunas, which this is. So we reached out to Backcountry and they were interested in what we were doing and how we were going to use it for sport performance. So they came on board to help us outfit our yard with it. It’s also a Canadian company, that was a draw as well.

Beyond the altitude training, are there other benefits? 

Well, I haven’t looked into the research as much on this, but I have chronic issues with systemic inflammation. It comes and it goes, but it’s not really predictable and it doesn’t make any sense. I’ll be in a period when I’m highly inflamed and old injuries I have will resurface. Like, I tore all the ligaments in my ankle a couple of years ago and when I have an inflammatory period my ankle gets really swollen for no reason and gets really difficult to move. And I have some weird stuff just throughout my body linked to this inflammation.  I don’t know the research as well but I know sauna use is linked to helping your body process and limit that kind of inflammation. So I was pretty interested in using it for that reason. And that’s the reason we use it for throughout the off-season, or how I use it, helping my body keep that under wraps. It’s kind of an N=1 experiment, but so far it’s working! 

You mentioned a lot of this is backed by research. Where should people look if they want to get deeper into this? 

I’m looking at peer reviewed, primary research. Studies that are experimental – a randomized, controlled trial – and that are published in peer reviewed journals. If you’re interested in the science  evidence informed practice that is not just pseudo-science and grandiose claims, I would recommend just using Google Scholar and it will filter the search out to more academic sources. There are a lot of studies on it. It’s pretty available.