One climbs up a four-thousander mountain without any problems from sea level, the other gets sick and has to turn around. Altitude sickness is no stranger to mountaineers. But now that more and more trail runners and hikers are looking for something higher, they are sometimes faced with surprises along the way. 

Out of breath, headache, nausea. Disastrous for sports performance. What exactly is altitude sickness and how can you prevent it? Spoiler alert: with the right preparation you will soon also be running up that four-thousander, or higher.

What is altitude sickness?

The body needs oxygen to function. The required amount is the same at any altitude. But at altitude, the air pressure and therefore also the oxygen pressure decrease. The body will have to adapt to this thinner air in order to get enough oxygen. If this adaptation, called acclimatization, does not go well, altitude sickness can develop. Acute altitude sickness affects some more than others. This has more to do with predisposition than fitness. Acute altitude sickness can arise from 2,500 meters and can be recognized by shortness of breath, headache, nausea, poor sleep and lack of appetite. Far from ideal if you want to achieve a sporty performance. Good acclimatization is therefore necessary.

How does the body adapt?

But how exactly does acclimatization work? The most noticeable adjustment of the body involves faster and deeper breathing and an increased heart rate. They ensure that more oxygen can be absorbed. This system switches on within a few minutes. Another known mechanism is the increase in the concentration of red blood cells. This allows more oxygen to bind in the blood and thus be transported to the tissues. The first days at altitude this happens because you urinate more. This makes the blood thicker and the concentration of red blood cells automatically increases. Only over time, days to weeks, will the body actually start to produce more red blood cells and thus be able to transport more oxygen throughout the body. That is the well-known effect of a so-called altitude stage.

How can you prevent altitude sickness? 

Although you cannot completely prevent acute altitude sickness, you can reduce the risk of it. For example, by following an ascent protocol in the mountains. That means ascending a maximum of 300 meters each day and taking a rest day after every 1,000 meters. It is also important to take it very easy for the first few days and to let your body get used to the altitude slowly. 

But there is another way, which is hypoxia training. Then you expose your body – before departure – to a training stimulus in oxygen-poor air for short periods. This way you can get used to presenting at height, while you are still at sea level.

The growing number of high-altitude chambers in the Netherlands, but also in Belgium at Fisiotics, among others, proves that this is an approach that is on the rise. There is even an Altitude Center in London that is completely dedicated to this form of training. It is also known that several well-known top athletes and climbers use this form of training. This includes the Flemish alpinist Sofie Lenaerts, but also Jur Rademakers, who used altitude training in preparation for his ‘7 Summits in 1 Year’ project.

How does altitude training work?

To bring about changes in the body, a training stimulus is needed. That works in muscle building, but also in pre-acclimatization. Training in an altitude chamber or with a special device and mask temporarily creates a state of ‘hypoxia’. Hypoxia means a lack of oxygen reaching the tissues and cells. This training stimulus should lead to an adjustment and improvement of the system. Hypoxia training improves oxygen transport within the body, which improves performance, but also reduces the risk of acute altitude sickness. With this form of altitude training you train your lungs and body to use the available oxygen more efficiently. In addition, it is assumed that this form of training also affects the mitochondria. These are the energy factories in our cells. They can convert sugar and fats into energy with the help of oxygen. By regularly breathing oxygen-deficient air, these mitochondria start to function better and more efficiently.

Tips for hypoxia training 

Do you want to get started with hypoxia training? In the Netherlands and Belgium there are only a few publicly accessible altitude rooms, usually located in a gym. But you can also rent or buy a ‘high altitude’ device yourself. With these devices you can simulate air up to an altitude of 6,000 meters. When you get started, keep the following in mind: 

• Do not train too hard and not too often; 2 to 3 times a week is sufficient. 
• Keep this up for at least 3 weeks. Longer is better; 6 to 8 weeks is ideal. 
• Pay close attention to your oxygen saturation percentage during training. That is now the most important training variable instead of heart rate or power. Make sure you don’t drop below 82%.
• Emphasize endurance and add just a little bit of interval. Only do this by playing with the height, speed, incline or weight of the pack. 
• Ensure adequate recovery between workouts. 
• Get advice from an expert in altitude training and create a suitable training schedule together. 
• 
  In short, take the time to acclimatize right away, don’t pass yourself by the first few days and invest in hypoxia training if you want to be sure that you perform optimally at height. With that preparation, no mountain will be too high. 

An article from height line NKBV written for Rinske Brand

Meer weten?

Advise about altitude training in Belgium  hier.

Full article from Dutch mountain magazine “hoogtetraining” Hoogtelijn.