CEU Article Title: Altitude Training
When it comes to performance, the more oxygen a person can assimilate, the better the performance. Everyone has a limit, and this limit is referred to as our VO2 max. VO2 max is the maximum capacity of an individual’s body to transport and use oxygen. The higher the number, the bigger your aerobic engine. Genetics plays a major role in a person’s VO2 max and heredity can account for up to 25-50% of the variance seen between individuals. The highest ever recorded VO2 max is 94 ml/kg/min in men and 77 ml/kg/min in women. Both were cross-country skiers. (1) Other athletes that post high numbers are cyclists, swimmers, runners and rowers.
VO2 max is expressed in ml/kg/min or, milliliters divided by the person’s weight in kilos divided by time. The reason we consider a person’s weight is because, if two different people assimilate the same amount of oxygen in milliliters, the smaller person would have a higher VO2 max. Think of it this way: two people might be processing the same amount of gas with the same size engine, but one has a smaller car!
In elite athletes, VO2 max is not a good predictor of performance. The winner of the Tour de France for example, cannot be predicted from maximal oxygen uptake alone. (2)
Perhaps more significant than VO2 max is the speed at which an athlete can perform at their VO2 max. Two athletes may have the same level of aerobic power but one may reach their VO2 max at a running speed of 10 mph and the other at 12 mph.
While a high VO2 max may be a prerequisite for performance in endurance events at the elite level, other markers such as lactate threshold and power are more predictive of performance. Again, the speed or performance (power) at lactate threshold is more significant than the actual value itself. Think of VO2 max as an athlete’s aerobic potential and the lactate threshold as the marker for how much of that potential they are tapping.
How can we increase our VO2 max?
Well, it depends on where you start. The fitter an individual is to begin with, the less potential there is for an improvement. There also seems to be a genetic upper limit and guess what? VO2 max decreases as we age. About 10% a decade, or 1% a year after the age of 25. However, in comparison, master athletes who continue to keep fit may decrease at half that rate. Remember, VO2 max is relative to our weight so if we gain weight as we get older, our VO2 max will decline, even if we keep training. Training can slow the rate of decline in VO2 max but becomes less effective after the age of about 50 (3).
What to do?
If you’re already fit as a fiddle and can’t drop any more body fat or body weight without sacrificing power, how can you uptake more oxygen and increase your VO2 max?
High Altitude Training.
What do we mean by altitude?
For this article, altitude is defined as any elevation over 5000 ft. If you already live pretty high or it’s inconvenient to train higher than 5000ft, you may consider high-altitude simulation in an Altitude Tent.
I’m 52 and have been a competitive cyclist for almost 25 years. I had already won gold medals at the Huntsman World Senior Games. I’ve been testing my VO2 max at the same place with the same doctor for 15 years. In the last year, my VO2 max went up over 10%! Keep in mind; I was already a highly trained athlete. How did I do it? By sleeping in a Hypoxico altitude tent and using an adapter to train on my wind trainer.
Here’s how it works.
No matter what elevation you are at, the air still contains 20.93% oxygen. The difference at altitude is lower barometric pressure. As a result, there is less partial pressure of oxygen in the air, resulting in less oxygen entering the lungs. (4) As the body perceives less oxygen the kidneys secrete a hormone from bone marrow called erythropoietin (EPO) which then stimulates red blood cell production which allows for greater oxygen-carrying capability when you return to sea level. Should we all live at high altitudes? Can we? Not really. Besides, it turns out that acclimating to altitude doesn’t completely counteract the additional stresses of increased heart and respiration rate of performing at altitude.
Altitude simulation systems or altitude tents have enabled athletes to not suffer from the stress of the higher altitudes and more intense workouts. Although studies aren’t all conclusive, it seems it’s better to sleep high but train low. This means you would have to get in your car (unless you have a helicopter) and drive up a mountain, sleep, and then drive back to train. Not an easy endeavor, especially if you live in Southern California and have to deal with traffic.
How long does it take to acclimate? It depends. As the altitude becomes higher, so does the acclimation period. Training for 14 days at or above 6,500 feet (as at the U.S. Olympic Training Center in Colorado Springs) or 28 days at or above 8,000 feet are currently the best recommendations for athletes wishing to compete at similar elevations, while it may take up to 14 months to completely adapt to the extreme altitude of 13,000 feet. (5)
Every Second Counts
Prior to my major races, I would stay in Big Bear, Ca, Park City or Brian Head, Ut. Since I won both of my National Championships with less than two seconds to spare, every little bit of training, resting, nutrition and yes, red blood cells made a difference. These mountain trips were not only costly, but it was difficult to be away from work for that long. Not to mention, cycling alone on the side of a mountain with no support can get precarious. On one of my training days, there was a 50+ degree temperature change in the weather! There is very little traffic on a mountain road and no convenient stores to acquire food when you need it. Consequently, I became dehydrated.
What About a Tent?
I researched altitude tents and settled on a Hypoxico tent. Some people have a hard time with altitude and others don’t seem to be affected as much. Unlucky for me, altitude affects me greatly. Every time I competed at altitude, I immediately got dropped from the pack. Once I started using the tent all of that changed.
A tent goes over your bed which could be at sea level and a generator pumps in air with a lower concentration of oxygen, 12-15% (below the 20.9% at sea level), which is roughly equivalent to the amount of oxygen available at the high altitudes often used for altitude training. I sleep inside the tent, but train outside (at normal oxygen concentrations 20.9%). With the generator I can slowly increase the altitude as my body adapts. I use a pulse oximeter every morning to check my resting heart rate and oxygen saturation. A pulse oximeter is a convenient noninvasive measurement instrument. My unit has a pair of small light-emitting diodes (LEDs) which I insert onto my finger. One LED is red and the other is infrared. Absorption at these wavelengths differs significantly between oxyhemoglobin and its deoxygenated form; therefore, the oxy/deoxyhemoglobin ratio can be calculated from the ratio of the absorption of the red and infrared light. As my body adapts to the altitude I can slowly increase the altitude all the way up to 13,500 ft! Hypoxico also provided me with an adapter that I can use on my stationary bike to train at different altitudes based on oxygen saturation using the pulse oximeter. I can not only sleep at altitude but also do short bouts of training as well.
When it comes to sleeping in a tent everyone is different. You’ll have to learn how the altitude or lack of oxygen might affect you. I’ve found it’s best to not sleep in the tent the night before a competition or, if I’ve increased volume or intensity in my training. When sleeping at altitude, the body is additionally stressed and not recovering as much. In my experience, my resting heart rate is invariably 8-12 beats higher when sleeping in the tent. In a few instances, I’ve gotten sick. It’s a learning process.
Some researchers believe performance is enhanced from the additional red blood cells or blood volume, while other researchers believe the increased performance is from economy of oxygen utilization. My hematocrit level, which is an indicator of the proportion of blood volume that is occupied by red blood cells, went up from 42 to 49.6! That’s an increase of more than 10%! At 50, a cyclist gets kicked out of the Tour de France and is suspected of doping. I’m getting this close by sleeping and training in an altitude tent.
Whatever the mechanisms are, the bottom line is that there are many benefits of altitude training. And I’ll take all the help I can get!
Give it a try.
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(1) Astrand P-O and Rodahl K. (1986) The Textbook of Work Physiology: Physiological Bases of Exercise (3rd ed.). New York: McGraw-Hill
(2) Energetics in marathon running. Medicine and Science in Sports. 1969 1(2):81-86
(3) Wilmore JH and Costill DL. (2005) Physiology of Sport and Exercise: 3rd Edition. Champaign, IL: Human Kinetics
(4) Robergs, R.A. & Roberts, S.O. 1997. Exercise Physiology: Exercise Performance and Clinical Applications. New York: William C. Brown
(5) Graetzer, Dan. High Altitude and its Effects on Exercise Performance: http://www.sumeria.net/oxy/altitude.html