A large part of my training philosophy lies in the simple realm of stimulus and adaptation. My mind has returned to these ideas for the past year as I’ve tried to flesh out these ideas. In writing my book, I had to really work to try and turn the ideas in my head into something useable. I even took to my home painted whiteboard wall to try and figure out how to make sense of it all.
Recently, I was working on a piece on defining amplifiers and dampeners of adaptation. Altitude is an obvious factor that can affect adaptation. We always think of it in terms of going to altitude to train and/or sleep so that we can get some nice aerobic plus red blood cell adaptations. The majority of altitude or hypoxic related ideas are related to getting this nice boost in Red Blood Cells. There’s a large market for people who want to attempt to get a heads up on that by buying an altitude tent so they can sleep and spend a large amount of time at altitude. Some people even make their whole house at simulated altitude to gain a larger training affect. While we can debate whether or not simulated altitude is the same (and there’s some recent research that it isn’t quite the same), the question that popped to my mind is the following.
If we go do a hard workout at sea level then come back home and spend time in our altitude tent what’s the effect? You are essentially stressing the body by running and then going into a different stress of simulated altitude, which will change certain hormonal responses upon entering the tent. Could we change adaptations based on spending time at altitude? Perhaps it would change cortisol levels and reduce recovery, or maybe doing a tempo run followed by recovery at altitude would supercharge the hypoxic activation of a pathway like PGC-1a.
In fact, I devote a paragraph or two in my book to the topic:
“Lastly, especially with the invention of artificial altitude, we can easily use altitude to modify adaptation. We can challenge workouts and hope for spikes in aerobic adaptations by making a workout be performed at altitude. Or, an idea that has not yet been researched, we can manipulate the recovery and presumably the adaptations by making the post workout recovery take place in altitude. These could be positive or negative influencers on adaptation”
But perhaps I should change the “has not yet been researched yet.”
A new study entitled “Influence of hypoxic exposure on hepcidin response in athletes” is the first study I’ve come across that looks at what happens when we recover in altitude. What they did was have their subjects do 8x3min at 85% max aerobic velocity interval session on the treadmill. Then they randomly assigned the runners to either spending the next 3 hours in simulated hypoxia(2,900m altitude) or normoxia (sea level). They then took blood after this period and after 24hr of recovery. The goal was to look at inflammation, iron, ferritin, EPO, and hepcidin to see if how they recovered (altitude vs. Sea Level) influenced these parameters.
Out of all the responses, Hepcidin levels was the only parameter to show a significantly different response. In hypoxia, hepcidin levels were lower 3 hours post exercise than in normoxia. Hepcidin is a hormone produced in the liver that lowers iron levels in the blood. In another study it was shown that hepcidin levels post workout rise and likely prevent iron absorption. So what the authors in the present study conclude is that using simulated altitude for the 3 hour post exercise window might be a way to dampen the Hepcidin response and help the athlete retain high iron levels.
Of course, there could be other adaptation like consequences from limiting a hormone like hepcidin from rising post workout. But that’s for more research to figure out.
The interesting point of this study is that it’s the first to look at, and conclude, that manipulating recovery via spending time in altitude DOES cause some hormonal changes. It makes you realize that just using an altitude tent to sleep in may have more consequences than you expect.