Every race has its own complicating factors—some are hot and humid, while others require large amounts of climbing. Racing at altitude presents a specific set of challenging factors, especially for those who live and train closer to sea level.
As pressure increases with altitude, the oxygen available within the air decreases. This causes the heart and lungs to work harder to meet the oxygen demands of working muscles. An athlete racing at elevation can expect to see a higher heart rate for a given wattage or pace than they usually would at sea level.
Individuals who travel from lower to higher elevations commonly experience some sort of altitude sickness. Symptoms can include shortness of breath, an elevated heart rate, dizziness and nausea, but symptoms typical appear within a few days and subside in about a week.
With that in mind, athletes should arrive in adequate time for their body to get used to environmental changes. Acclimating to higher elevations is a slow process, but adaptations such as increased red blood cells and plasma do occur among those who live at higher elevations.
If arriving to the race site early is not possible, instead arrive as close to the race as possible before the effects of altitude can set in. Additionally, simulating reduced oxygen availability prior to travelling can help reduce the impacts of racing at elevation. Products such as altitude tents and masks reduce the amount of available oxygen in the air and promote adaptations similar to being at elevation.
Most athletes do not have the luxury of arriving two weeks before race day, nor do they have access to costly equipment, so race execution adjustments will need to be made. Heart rate should be the preferred metric to gauge effort level.
If the athlete attempts to maintain their sea level pace or power output at a higher elevation, they will be expending energy at a faster rate, ultimately creating more fatigue.
Additional hydration and nutrition should also be included to help meet these demands. A coach can be a good resource for guidance or technology; for example, TriDot's eNorm can make data-driven elevation adjustments specific to each athlete.
Racing at elevation presents new challenges when compared to racing at sea level, but with proper preparation and planning it can be feasible for any athlete, regardless of which elevation they call home.