Many people have heard of the benefits of altitude training. It turns out that the benefits aren't clear-cut, because while living at altitude has a stimulatory effect on red blood cell count, it also inhibits recovery and doesn't allow one to train as intensely. The response has been the so-called "live high, train low" approach, in which people live at high altitude, but do their intense training at low altitude. There are only a few places where this is possible, however, and it's certainly not possible for the everyday age grouper.
|Hypoxico altitude tent|
Enter altitude tents. These are portable airtight canopies that one puts over one's bed, and they're connected to large, heavy, expensive ($5,000) units that look like portable generators. These units substitute nitrogen for oxygen, and thereby create lower oxygen percentages, much (but not exactly) as one would find at altitude. Athletes sleep in these tents at up to 10,000 feet or so for a period of weeks leading up to a race. The tents can be effective, but they're uncomfortable to sleep in due to noise from the generator and buildup of heat and humidity within the tent. I owned one of these for a year or so, and I found that I had so much trouble sleeping in it that the downsides outweighed the benefits. Still, I considered renting one of these for a couple of weeks before Lake Tahoe; they can be found for a few hundred dollars for brief periods.
In the course of my research, though, I stumbled upon a solution I hadn't seen previously: the Altolab system. These aren't cheap -- about $600 -- but in the world of altitude simulators, that's not too bad. I decided to take the plunge, reasoning that I could benefit from altitude training for races leading up to Tahoe as well.
The Altolab system works on the principle of intermittent hypoxic exposure, i.e., brief periods of relatively intense hypoxication with recoveries in between. In an altitude tent system, you might sleep for 8 hours at a simulated 10,000 feet. With Altolab, in contrast, the protocol is one session per day, and the session is 6 reps of 6 minutes of hypoxication, followed by 4 minutes of breathing normally. The key is that the Altolab can simulate much higher altitudes than the tents -- if a tent can simulate up to 10,000 feet, a typical level, the Altolab can simulate well in excess of 20,000 feet. In the world of altitude training, a tent can be thought of as a very long Z2 run, whereas the Altolab is more like intense hill repeats for a shorter period. Research on runners and cyclists has shown a clear performance benefit from intermittent hypoxic exposure, a technique that was originally developed by the former Soviet Union.
All of this may sound speculative and gimmicky, but it quite clearly works. The Altolab comes with a fingertip device that displays blood oxygen levels in realtime. Normal oxygen saturation is about 98%, but using four Altomixers, at the end of six minutes, I can see my blood oxygen levels dip to about 75%. This is interesting to play with: take just one normal breath in the middle of a 6-minute interval, and after about 20 seconds, my blood oxygen level spikes back up into the mid 90s before dropping again. In other words, the altitude simulation demonstrably works.
The AltoLab training protocol is pretty straightforward: an hour a day (6 minutes on, 4 minutes off, and repeat 6 times) for 15 days. In those 15 days, one gradually adds black Altomixer stacks according to a prescribed schedule, which gradually increases simulated altitude. After that, every three weeks, one performs a 5-day "top-off" session at a pretty high simulated altitude. These sessions are easy to do while watching tv or doing anything passive, although they tend to make one a little spacey, so no driving, and probably no reading.
An important note: the soda lime in the green hypoxic silo, which absorbs CO2, becomes exhausted after a couple of uses and must be replaced. These silos are quite pricey ($15 ea or so, even if purchased in bulk). Thus, if bought in the usual way, each day of altitude simulation will run $7.50-$8.00. That's still not exorbitant compared to the cost of buying or renting a hypoxic tent, but there's a better way: one can purchase soda lime directly from a medical supply company and simply replace the soda lime in the hypoxic silo. Using this approach drops the price to about $1/day (not counting the initial investment), which is very affordable. Below is a video showing how it's done -- though, note that the manufacturer does not endorse this approach.
In all, this is a pretty cool product -- easy to transport (unlike an altitude tent and generator), and reasonably affordable, considering the alternatives. I've completed a 15-day cycle, and I'm now in the midst of my first top-off phase. It's been pretty straightforward, although it does make one tired afterward. I'll be interested to see the results in my races!