Wednesday, August 8, 2012

Product Review: Altolab Hypoxic Trainer

A few weeks back, I engaged in my annual stupid tradition of impulsively signing up for an inaugural Ironman in a beautiful place that presents an opportunity for an "interesting race report experience."  In 2009, it was the Cozumel Mosquito Coast.  In 2011, it was Tropical Storm Wales.  This year will be Mont Tremblant, and in 2012, it'll be Lake Tahoe.  Tahoe will be gorgeous; the problem is, the swim is at 6,200 feet, and the bike climbs well above 7,000 feet.  It won't be possible to get there more than a couple of days in advance, so I got to thinking, how am I going to do this?  And I did some research.

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.

The Altolab system is dead simple to use, although it's somewhat hard to describe.  It consists of three basic parts: (i) a breathing tube with mouth piece that's connected to a bacterial filter; (ii) a green hypoxic silo cylinder; and (iii) several "altomixer" cylinders.  The green hypoxic silo consists of particles of soda lime, a chemical that absorbs CO2, and the altomixers contain sponges that simply inhibit air flow to a minor extent.  The functional principle is that, when one inhales, the gas consists of a high percentage of oxygen.  The oxygen is absorbed by the lungs, and when it's expelled, it contains more CO2 and less oxygen, along with some nitrogen.  Normally, when one inhales fresh air, the level of oxygen inhaled remains constant.  The Altolab changes that, because when one exhales into it, the soda lime in the green hypoxic silo absorbs the exhaled CO2, leaving only a reduced level of oxygen, as well as the nitrogen.  On the next inhalation through the Altolab, the removed CO2 is replaced by additional oxygen and nitrogen (fresh air), but the exhaled nitrogen remains.  The overall effect is that, when one breathes through the Altolab, the percentage of oxygen inhaled decreases, and the percentage of nitrogen inhaled increases.  (This is why the system is different than breathing through a long tube -- there, the CO2 remains, and you'll eventually hyperventilate trying to get oxygen.)

An Altolab kit comes with 6 black "altomixer" cylinders, and each cylinder used increases the simulated altitude by about 5,000 feet.  Use four of them, and you're essentially breathing at 20,000 feet, which is like being on the peak of Denali.

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!