With the 2014 Sochi Winter Olympics around the corner, it is a great time to discuss training at altitude and its impact on competitions. Athletes who participate in Winter Olympic events must train and compete where the total air pressure is much lower and there are fewer oxygen molecules present. For athletes to perform successfully with less oxygen in every breath, they must spend an extended period of time at altitude while their bodies make physiological adaptations to the environment. That familiar feeling of exhaustion when you climb a flight of stairs at 6000 feet above sea level can be good for you, if you can push past the initial adjustment period and learn how to train effectively up there! Altitude affects every athlete, regardless of his or her sport. I will discuss some of the long-term changes that come with altitude training, as well as the acute effects of elevation on hydration, respiration, and the body’s general ability to maintain balance with less available oxygen. Understanding the challenge of performing at altitude will help you in your future training endeavors and give us all a sense of appreciation for the extreme conditions that winter Olympians face in their sports!
Training in the Elements
Your first questions surrounding altitude training probably relate to how long you need to train at elevation, what constitutes elevation, and what kind of physiological changes occur in your body. Many training facilities at altitude, such as the U.S. Olympic Training Center in Colorado Springs, are located at elevations 6000 ft or more above sea level. It is necessary to acclimatize, or gradually adjust, to the new conditions because too sudden of an increase in training intensity can lead to harmful effects like altitude sickness. Acclimation (or acclimatization) enables the body to cope with the shortage of oxygen. For every 300 meters above 1500 meters elevation (about 5000ft), your VO2max decreases by 1.5 to 3.5%. Put another way, at 6000ft there is about 80% of the available oxygen you get at sea level, so marked changes in performance are bound to occur without proper adjustment. Moderate altitude sickness will include symptoms like headache, nausea, loss of appetite, poor sleep and general fatigue. Acute sickness is more likely to happen in mountain climbers who ascend too quickly or athletes who begin training too intensely; it will be minimized if you gradually ramp up your training at a particular elevation level.
While you may be able to avoid altitude sickness, at 6000ft there are a few important things to be aware of. Much like being on an airplane where the cabin pressure is reduced, you are going to be more dehydrated at altitude than at sea level. You exhale and perspire more at high altitude where the air humidity is lower, causing you to lose up to a quart more of water per day than you normally would. Additionally, one’s calorie expenditure may seem to be higher during altitude training, but this is less likely to be due to being at elevation and more likely to be attributed to the hard workouts athletes generally go through while training up there. In the short term, your body will undergo the following changes: ventilation (respiratory rate) increases in response to a lower amount of oxygen in the blood, blood then becomes more alkaline (meaning less acidic) as you hyperventilate, and this alkaline state in turn signals your body to breathe less than you should in order to get substantial oxygen to your tissues. Confusing? Good thing the human body is able to make some smart changes that enable you to stay at altitude.
A key component of adapting to altitude involves a protein called hemoglobin. It binds to oxygen in the lungs and carries it in the blood, eventually releasing it to tissues that need it, such as muscle. At high altitudes, the amount of hemoglobin increases, enabling the body to transport more oxygen from the lungs to tissues. In the initial days of being at high elevation, hemoglobin will have a reduced affinity for oxygen such that it is both harder to capture from the lungs but also easier to release oxygen to the tissues that need it immediately.
More long-term effects make training at altitude valuable as the body improves its oxygen delivery efficiency. The body naturally produces a hormone called erythropoetin (EPO) that stimulates the production of red blood cells that in turn carry oxygen to tissues. More red blood cells can mean more oxygen delivery, helping the athlete who performs anything aerobic (middle and long distance races, for example). Other changes include growth of small blood vessels and enhanced buffering capacity (ability to process the build up of acid waste in the body). Predominantly anaerobic athletes who perform sprint or power events can still benefit from altitude as the thinner air can dramatically increase the flight of a ball or the height of a jump. An analysis of the FIFA world cup stadiums at moderate altitude in 2010 showed that a soccer ball could fly up to 4 yards further on an average goal kick simply because the air density was lower!
How Long Do I Need to Be Up There?
For the purpose of long-term physiological enhancement, an athlete should consider staying at altitude for multiple weeks. Some training camps last from days to weeks, but the general feeling among athletes (myself included) is that you begin to feel better in your training by the end of one week. Staying for at least 2-3 weeks will allow your body to make those changes in oxygen efficiency that will help you perform.
Any athlete with altitude training experience will tell you it’s no picnic up there. The initial days of training can be grueling and intense, and things you could easily perform at sea level suddenly seem difficult in the thin air. Once you push past that initial challenge, your body gets stronger and more efficient, and you develop some helpful mental toughness along the way. Done best with a team, altitude training takes perseverance and dedication. That hard work can manifest itself in performance gains in your next competition. Many Winter Olympic athletes develop these long-term changes as a result of extended training periods in the mountains, but any athlete can benefit from training up high. Pay attention to your hydration, sleep, and nutrition in the early days of a training camp, stay committed to a multiple week training program at altitude, and get ready to feel the positive changes in your body when you complete it! If you are interested in learning more details regarding some of the physiology discussed here, I recommend exploring the website: altitude.org. Happy training!