Whether you’re planning on ascending high into the Alps or Rockies, or just want more power for crushing your buddies in sea-level criteriums and road races, breathing in the thin air of high elevation may help you improve your performance. Cycling performance is largely a function of oxygen uptake, delivery, and utilization by the body; and altitude training, whether by traveling or sleeping in a tent, may help you bring more precious oxygen to your working muscles.

The Physiology of Altitude

As we ascend in altitude, there is a drop in barometric pressure that is associated with a decrease in the partial pressure of oxygen. This starts a cascade of decreasing oxygen pressures in the lungs, arteries, capillaries, and, eventually, tissues. The end result is an insufficient supply of oxygen to tissues (hypoxia) that is especially apparent during exercise when the oxygen demands of working muscle increase. Because the oxygen cost of work at altitude is unchanged from that at sea level, to train or compete at the same absolute power requires adaptations that overcome or minimize this decrease in oxygen supply.

In general, all the various systems of the body respond and adapt to the hypoxic stress of altitude. Some of these adaptations have the potential to enhance endurance performance, while other changes may actually hinder it.

The body’s initial response to altitude is to increase breathing rate and heart rate at both rest and during submaximal exercise. In addition, blood is concentrated by reducing the fluid or plasma component. Collectively, these changes improve oxygen uptake by the lungs and its delivery to tissues. The disadvantages of these changes are that perceived exertion at any workload is increased and circulating blood volume is reduced.

With prolonged altitude training and continued acclimatization further adaptations take place. Perhaps the most sought after altitude adaptation results from kidney hypoxia that stimulates release of erythropoietin (EPO). In turn, EPO stimulates red bone marrow to increase production and release of new red blood cells (RBC). This increase in circulating RBCs leads to enhanced oxygen carrying capacity of blood and, therefore, improved oxygen delivery to tissues. At the same time, blood plasma volume increases so that overall blood volume rebounds toward sea level values.

Why We Train at Altitude

Altitude training can be an effective way of improving your cycling performance, at any elevation. Both acclimatization to altitude and training at altitude have been shown to stimulate the following adaptations:

· enhanced oxygen uptake in the lungs

· increased red blood cell numbers to improve oxygen delivery to tissues

· skeletal muscle changes which improve oxygen use by muscle

· increased buffering capacity to possibly delay the onset of fatigue

Taken together, these adaptations improve cycling endurance, sustainable power, and speed. By increasing the amount of oxygen your muscles can get and utilize, altitude training increases the amount of work you can perform before you reach your maximum sustainable power, as well as the work you can sustain when you get there. When you’re climbing a mountain with the pack, these adaptations make it easier to stay with the lead group’s pace, or give you the ability to push their pace and put them under pressure. This is true whether the climb begins at 25 m or 2500 m above sea level.

Before starting on an altitude training program it’s important to understand that proper altitude training is complex and success involves balancing some potential risks with proper nutrition, training, and rest. Some factors that have to be considered include:

a) iron status and ensuring adequate iron stores for optimal red blood cell production

b) increased risk of dehydration

c) poor sleep quality

d) prolonged recovery times

e) a reduction of maximal training intensity that may later negatively affect sea level performance

f) loss of heat acclimatization from training in cooler temperatures

g) suppression of appetite

h) immune system suppression with an increased risk of upper respiratory tract infections

Simply put, there is no altitude training plan that will suit every athlete. An optimal program needs to account for your unique physiology as well as the physical demands of your goal event.

Live high, Train Low

Training at altitude for the purpose of improving sea level performance is perhaps one of the most controversial topics in altitude training. Overall, research tends to favor the Live High-Train Low (LHTL) protocol. The key component of LHTL training is that interval workouts at sea level intensities are maintained, while still gaining the benefits of altitude acclimatization by living at altitude.

Since there are not many places where you can live between 2,100 m (6,890 ft) and 2,700 m (8,800 ft) for at least 8-10 hours a day, and descend to train below 1250 m (4100 ft) for improved workout quality, many people use artificial altitude environments to sleep at simulated elevation wherever their home happens to be. These tents and rooms create a hypoxic environment for sleeping, which may allow you to achieve many of the same benefits normally seen from living high above sea level. It is very important to use a tent or room properly, as many factors, including iron status, sleep quality, training intensity, sleeping “elevation”, and individual variability govern whether you will see significant progress or none.

For the LHTL method to work, whether you’re actually traveling back and forth or climbing into a tent, there are some factors you have to keep in mind:

1) You need at least four weeks of LHTL training and living to reap any substantial benefits and you’re most likely going to schedule this period as a lead-in to competition.

2) Since you’re spending considerable time at altitude each day, adequate recovery periods between workouts is critical. You may need more recovery between interval workouts than you did when you were sleeping and training in low-elevation conditions.

3) Your sea-level competition should take place within 2-3 weeks after LHTL training. Most athletes require at least a week after a LHTL camp to feel “race ready.”

Competing at Altitude

When preparing for competition at altitude there are basically three choices, as listed below in order of preference.

Arrive at altitude at least three weeks prior to competition

This allows for adequate altitude adaptation as well as time to develop a sound pacing strategy. The first week at altitude should involve easy exercise to allow time for acclimatization without the added stress of training. This minimizes the risks of acute mountain sickness and its associated headache, nausea, poor appetite, fatigue, disturbed sleep, and lethargy. The remaining 2-5 weeks constitute the primary phase of altitude training and should incorporate the training modifications listed below, based on an athlete’s standard, low altitude program.

· Altitude: The recommended training altitude is from 1,900 m (6,000 ft) to 2,700 m (8,800 ft), but should also reflect the average actual competition altitude.

· Training Volume: Volume should be decreased by 10-20 % of sea level values and gradually increased by 3-5% each week.

· Training Intensity: Interval workout intensity should be decreased by 5-7% over the first week and then increased by 0.5-1% per week.

· Recovery: Recovery time for interval workouts needs to be doubled initially, and then decreased by 2-3% per week. It should always remain at least 10% above sea level recovery times.

· Pacing: Due to the increased recovery time at altitude following short, intense efforts, the ability to appropriately pace an all-out effort is critical for performance at altitude.

Arrive two weeks prior to competition

Arriving two weeks prior to competition allows for adequate time to develop pacing strategies, improve sleep quality and appetite, and take advantage of RBC changes. Oxygen delivery to working muscles is generally improved over shorter stays, though there may still be issues with decreased blood volume and buffering capacity.

· Altitude: The recommended altitude is between 1,900 m (6000 ft) and 2,700 (8,800 ft).

· Training Volume and Intensity: Both volume and intensity should be decreased by 30-40% initially (first 4 days) and over the following 10 days gradually increased back to 75-85% of sea level doses.

· Recovery: Recovery time for interval workouts needs to be doubled initially, and then decreased by 2-3% per week. It should always remain at least 10% above sea level recovery times.

· Pacing: The focus of training should be pacing strategies.

Arrive as close to race time as possible

In this protocol there is no time for acclimatization or adaptation to altitude prior to competition. In fact, the goal is to avoid an altitude stimulus, which initially has components that can potentially decrease performance. Basically, you’re getting there and doing your event before the detrimental aspects of being at altitude kick in. The major disadvantage to this protocol is that there is no time to develop a sense of pace. However, if you have competed or trained at altitude previously, then this disadvantage may be minimal.

In summary, altitude training has a proven role in the enhancement of cycling performance. However, just like any other training stimulus, there are right and wrong ways to use it, certain periods of training when it is most useful, and a lot of individual variability in how individuals respond to it.

Andy Lapkass is an Expert Coach for Carmichael Training Systems, Inc. (CTS) and an experienced cyclist and mountaineer who climbed to the summit of Mount Everest three times. To find out what CTS can do for you, visit www.trainright.com.