Preparing To Race At Altitude: Ultra X Tanzania

James Barber Altitude Centre

Written By James Barber

James’ is the lead performance specialist at The Altitude Centre London. His focus is on maximising performance with runners and climbers, providing bespoke 1-2-1 coaching and sport science support to amateur and elite level runners, 8,000m climbers, and many more! 

26 September 2022


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Preparing to Race At Altitude


The inaugural Ultra X Tanzania promises to be an incredible race. 5 days of running from Lake Chala on the Kenyan border to Namlock Nature Reserve and The Blue Mountains ticks every box for an ultra runner’s dream event; incredible scenery, wonderful people, and of course testing terrain befitting of an event of this stature. When it comes to the testing terrain, the team at Ultra X have really taken this to new heights. Literally.

Stage 3 sees runners take on a test unique to Ultra X Tanzania. The day’s course starts from the campsite at Marangu and heads up…and up… and up. Over 2600 m elevation gain later, participants will arrive at the Horombo Huts, the high point of the course at 3750 m above sea level. By this point, not only will hours of climbing, starting in the dark, be taking its toll, but so will the altitude itself.

The Problem With Performing At Altitude


Altitude is an endurance athlete’s worst enemy during an event. At the 1968 Mexico City Olympics, held at an altitude of 2200 m, the winning times in the endurance races were between 6-10% slower than previous and subsequent years, and Ron Clarke, world record holder in the 10,000 m famously collapsed over the line where he remained unconscious for 10 minutes. With Ultra X Tanzania heading to a high point 1 mile higher than Mexico City, the potential for altitude to impact performance is clear.

At 3750 m, the availability of oxygen in the air is reduced by approximately a third compared to sea level, meaning the body has less oxygen available to it for exercise and normal vital functioning. To counter this, breathing rate and depth will instantly increase to maintain the flow of oxygen into the lungs, and heart rate will pick up to pump more blood to the body in an effort to supply the muscles and the brain with sufficient oxygen. However, the amount of oxygen in the blood, measured as blood oxygen saturation, will drop at high altitude, especially during exercise, because the supply of oxygen simply cannot match the demand from exercising muscle and the brain.

As a result, we can expect to see important markers of endurance performance like VO2max and lactate threshold reduced by between 10-25% at this altitude. However, it is not just the effect on performance that we need to be aware of. Rapid ascent to 3750 m presents a significant challenge to the body, and could induce symptoms of altitude sickness. At a mild level, altitude sickness is usually characterised by a headache and one other symptom, most commonly nausea, but it is the potential for altitude sickness to progress to more serious symptoms and outcomes that can be concerning. Whilst avoidable, it is important for anyone heading to altitude to be aware of the potential for a serious adverse response.

Preparing For Altitude


The good news is that there are simple steps that can be taken before even stepping foot on the mountain, to mitigate the impact of altitude on the body, and help maintain performance levels and stave off altitude sickness.

Altitude is a stress on the body. One that it doesn’t like, but one that when exposed to in controlled doses, it will respond and adapt positively to. Enter altitude training. Where altitude training was once the preserve of the elite athlete, simulated altitude training technologies have made it possible for anyone to begin the adaptation process before heading to altitude in the real world. Altitude generators simulate the conditions experienced on the mountain by reducing the oxygen content of air that the athlete breathes during training. There are a few different ways of using simulated altitude training to prepare for an event at high altitude, with options to exercise at high altitude, sleep at altitude or to conduct passive exposures to very high altitude called intermittent hypoxic exposure (IHE). The key is that all three techniques expose the body to hypoxic conditions and drop the blood oxygen saturation. In preparation for events like Ultra X Tanzania, athletes may choose to use any combination of these methodologies, with the best options dependent on your individual training and situation. With repeated exposures over time, the body adapts to improve its ability to cope with these low oxygen environments improving your ability to perform at high altitude.

The Altitude Centre Treadmill



· At high altitude, the availability of oxygen is significantly reduced (by about a third at the high point of Ultra X Tanzania)

· Endurance performance is likely to be impaired by 10-25% at this level depending on individual susceptibility

· Rapid ascent to high altitude also risks developing symptoms of altitude sickness like headache and nausea, or worse

· Pre-acclimation using simulated altitude training techniques, can prepare the body for performance at high altitude by kick starting the adaptations required to deal with hypoxia


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