The main challenge in the Volcano Marathon is the combination of the Distance, Altitude and Temperature.
Adequate training should be conducted so that competitors are fit to run a 26.2-mile marathon.
The impact of high altitude alone is significant in the Volcano Marathon. At 14,000 ft, the air has 43% less oxygen than at sea level. Because of the reduced air pressure at such high altitude, the volume of air you breathe into your lungs contains less oxygen molecules in each breath.
A few days acclimatisation is therefore mandatory for the Volcano Marathon, which is the reason why competitors must arrive in San Pedro three days prior to the race. Your body must adjust to the lower oxygen levels, and it is this process of adjustment that is called acclimatisation. Many changes can occur in your body during acclimatisation. One of the first things you will notice is that you breathe faster and deeper, to take in more oxygen. Therefore, you might feel short of breath when running during the first couple of days at San Pedro de Atacama. By race day, you should be somewhat adjusted to the altitude having spent 3 days at almost 8,000 ft. Staying hydrated from the outset of your trip is important as it aids your body in the acclimatisation process.
It is also important to note that regardless of acclimatisation, endurance running performance is significantly decreased at high altitude. It is impossible to run a marathon at high altitude as fast as at sea level. Everything is conducted a bit slower, and more breaks and rest stops may be necessary to avoid exhaustion.
The temperature will likely be 30 Degrees Celsius by the finish of the Volcano Marathon. It stands to reason that such hot temperatures will negatively impact running performance regardless of the low humidity levels (the air is dry in the Atacama Desert). Therefore, the importance of keeping hydrated cannot be emphasised strongly enough. Competitors will be required to carry hydration packs even though there will be aid stations (with water) every 8km approximately.