Dr. Kevin Sprouse has worked for years with EF Education-NIPPO as the team’s Head of Medicine. Here, he answers some of our most common questions about training and racing at altitude and how amateur racers can improve.
How does altitude affect an athlete’s physiology?
There is actually a lot that goes on when you go to altitude. The biggest driver is the fact that there is decreased oxygen availability: what we call partial pressure of oxygen. In response to that, there are physiological changes regarding everything from breathing patterns to fuel availability, even how you process fuel as a substrate for a given effort. For instance, a given effort that may be entirely aerobic at sea level becomes much more glycolytic at altitude, so it requires more carbohydrate to fuel it than it would at sea level. Since there is less available oxygen, people become shorter of breath, and there are changes in their serum levels — the hydration of the body. It takes time, depending on the altitude, to adjust to that. There are lots of things at play in regards to what an athlete will experience. Those things include their history at altitude, where they are coming from, and how high they will be competing. If you take an athlete who normally lives at 1,500 meters and they are going to compete at 3,000 meters, that will be very different to someone who maybe lives at sea level and is going to compete at 4,000 meters. A lot of times, people focus on it almost like it’s a switch that flips — you’re at altitude or you’re not at altitude — but in reality it’s a pretty big gradient.
For an amateur athlete, who doesn’t have much experience at altitude, what are the biggest things that they can expect to notice when they first go up for a high-altitude race?
If you take someone who lives more or less at sea level and you go up to a place like Leadville, Colorado (3,105 meters) then they are going to be short of breath walking up stairs and doing basic tasks, which can get to the head with an impending competition. You know that it is going to be difficult. What you will find is that even at a fairly easy pace, or what would be an easy climb, you are breathing much more rapidly. Your heart rate goes up, your breathing rate goes up, at an output that seems almost inappropriate. You’ve started that first climb and you’re huffing and you’re puffing, and your legs aren’t feeling good and your heart is beating too fast, and it’s physiologically difficult, but it’s psychologically difficult too, as you realize quickly that you are in for a pretty tough day.
The other thing that accompanies that is the need for greater hydration, because a lot of times the air at altitude is very dry, so your insensible fluid losses — what evaporates off your breath and off your skin — are much higher, and you also have a shift in fluid volume to accommodate some of the physiological processes that are occurring because of the altitude. So you need more fluid intake, and you need more electrolyte intake, and, like I said, you need more carbohydrate fuel intake, because you are going to burn through it at a much higher rate.
All of those things set you up to blow up much more quickly. If you are a recreational athlete, going out at what seems like a fairly easy pace and recognizing that you have a long day ahead of you, you can still blow up pretty quickly if that pace is based off of what you would do at sea level.
So, for an amateur athlete, the biggest thing to focus on is pacing, moderating your efforts, and not going into the red?
For sure. And recognizing that, if at sea level a threshold effort is, say, 240 watts, at altitude you might be looking at sub-200 as a threshold. Muscularly, it might feel very slow; it might psychologically feel very slow, but the cost of that effort is the same as if you were doing many more watts at sea level. And that is often hard to get your head around, especially as a recreational athlete who has trained for this, traveled for this; there is a lot of hype around the start of the race, the gun goes off, and even though it’s a long race, you tend to take off with all that excitement, but, if you do, or when you do, go into the red, it can take longer to come back out of the red, and to recover, because you just don’t have the available environmental substrates to draw on to recover. The oxygen is not there. You’ve depleted your glycogen tanks a bit more, and that takes time to replace. It is kind of a double-edged sword in that way, in that once you get there it is problematic, but it also takes a longer time to get back to a baseline pace.
What can an amateur rider do to prepare for a high-altitude race?
I think there are two things to look at. Ideally, we would tell someone to go up two to three weeks beforehand, but obviously most recreational athletes can’t do that. So if you are looking at when you can get there, it’s really just as many days beforehand as possible. There used to be this idea that if you couldn’t get there five days ahead of time, maybe come in thirty minutes before the race, and it had to do with the way that your serum volume shifts when you arrive, but really that is probably not warranted based on the science. Theoretically, there are some reasons why it might make sense, but practically the best advice is that if you can get there two or three days ahead of time, then take three. If it’s five or seven, pick seven. The more time you can spend there, the better. So there is that component: the arrival.
And then there’s what you can do beforehand at sea level to make sure that you are as fit as possible for your arrival. There are altitude tents that can be used at sea level; the literature on those shows that you really need to spend 12 hours in them per day for them to be beneficial, so people who get altitude tents and sleep in them for six or eight hours a night are probably not getting much of a benefit in terms of acclimatization. The research that is out there just would not support them being valuable tools in that way, but if you can spend 12 hours in there, or if you have one of these altitude rooms or access to one where you can sleep, maybe get up and have breakfast and then leave the altitude room, then that could be worthwhile. Obviously, those are not accessible to many people, but that is what you would be looking at.
There are altitude masks or hypoxic masks that you’ll see people wear. The short answer is that those are a waste of time. They may help your respiratory muscles, but they do nothing for acclimatization. Using saunas is something that I will have my athletes do if they are at sea level and they are going to race at altitude but don’t have time to get there early, or even if they do have time. We’ll have them spend thirty minutes a day, usually post exercise, in the sauna, just to kind of stimulate some of that hematological adaptation that they would normally see at altitude, to get that process going even though they are not at altitude. In short, arrive as early as possible and maybe use heat and some other stimuli at sea level to stimulate adaptations and simulate altitude.
When should an athlete taper for an event if they're going up to altitude to race?
I would definitely say that for a recreational athlete who is going to altitude and is maybe going to arrive three days ahead of time, then build your taper well before that, so that you go to altitude fresh. Don’t necessarily rely on those three days at altitude to taper, because they will be physiologically stressful, even if you are not doing anything. So, taper ahead of time and make sure your diet is good. I have a little bit of a bias as a doctor here, but I would recommend doing a panel of blood work six to eight weeks out from the event as well, just to make sure everything looks good from a hematological and a dietary standpoint.
Do amateur athletes benefit from doing altitude camps?
For most recreational athletes, I wouldn’t necessarily recommend that they spend their resources to go do an altitude camp without the right oversight, because, especially for a recreational athlete, that would involve a lot of resources, even if it’s just the time. Even for someone who is quite wealthy, to go spend two or three weeks at altitude is a lot of time, and it may go south. It may not work well for them, so it is not a tool that I recommend just widely adopting without some education and oversight.
Is that because they won’t be able to train as hard at altitude as they would normally?
Exactly. That’s why you hear about this strategy of ‘live high and train low’. What that is referring to is basically spending twelve hours of the day at altitude, but doing your training at sea level, where you can take advantage of doing hard efforts. If you just go live high for a training camp, you are really going to lose that top end. You may gain a lot of aerobic capacity, but you will lose a lot of that glycolytic capacity, and your ability to sprint or do shorter efforts, even in the three-minute to five-minute range, because there is a tradeoff. Nobody comes to a coach and says, I want to be much better at climbing and I want to get much better at sprinting at the same time. That’s not going to happen. It’s a physiological trade off. The better strategy, if you are going to do something across the board, is to live high and train low.