High Altitude Training

High Altitude training is the practice by some endurance athletes of training for several weeks at high altitudes, preferably over 2,400 meters (8,000 ft) above sea level, though more commonly at intermediate altitudes due to the shortage of suitable high-altitude locations. At intermediate altitudes, the air still contains approximately 20.9% oxygen, but the barometric pressure and thus the partial pressure of oxygen is reduced.[rx][rx]

To exercise at a high altitude means working in an environment with reduced atmospheric pressure. The oxygen tension of the inspired air is therefore decreased, that is, there is atmospheric hypoxia. Exercise increases oxygen requirements which must now be met in the face of this decreased oxygen driving pressure.

The purpose of a short altitude training camp (2-5 days) is to gain an understanding of how your body responds to exercise at higher altitudes. These short camps are not long enough to lead to an increase in oxygen-carrying capacity (the camp would need to be about 3 weeks long to have this impact). To do this, focus on your aerobic fitness by running, cycling, and swimming. If it’s possible to train above 5000 feet for a climb, for instance, that would be ideal. But if this isn’t an option, there are a few ways to increase the effectiveness of your workout. Find steep hills and hike and bike up them regularly.

General

  • General
    • The general assumption unacclimatized athlete is at a disadvantage compared to the acclimatized athlete competing at altitude
    • Utilizing the physiologic effects of high altitude acclimatization on hypoxia and exercise performance at both altitude and sea level is the primary driver of the utilization of altitude training among athletes.
  • Optimal Elevation
    • <2000 Meters: Not enough stimulus
    • 2000-2500 meters: 22+ hours per day
    • 2500-3000 meters: 12+ hours per day
    • 3000: no benefit above 3000 meters

Benefits of Training at Altitude

  • Improved aerobic capacity
  • Increased VO2 max
  • Increased erythropoietin (EPO)
    • Leads to a corresponding increase in red blood cell mass
    • Theorized to be the key acclimatization response that enhances both VO2max and performance
    • However, studies supporting this finding are variable and inconclusive
  • Increased Muscle buffer capacity
  • Improved pH regulation
  • More efficient exercise economy
  • Improved mitochondrial function and efficiency
  • Augmented skeletal muscle capillary-to-fiber ratio
  • Central factors (cerebral hypoxia)

Negative Effects of Altitude on Performance

  • Decreased Muscle Mass
  • Diminished efficiency of energy expenditure
  • Cardiac output decreases
  • Increased risk of dehydration
  • Decreased training intensity
  • Decreased power output
  • Longer recovery time

Practical Considerations

  • LHTH Model (live high, train high)
    • Investigation into this model has produced mixed results
      • Some show improved VO2max, performance
      • Others show athletes’ inability to maintain high-intensity training at altitude with a subsequent decline in performance
    • Limitations may result from tissue hypoxia and centrally induced reduction in exercise effort
  • LHTL Model (live high, train low)
    • Addresses the training intensity limitation seen with LHTH still achieves the benefits of acclimatization
    • This model is most commonly adopted by elite athletes and teams
    • Overall conflicting evidence
      • Some studies show benefits with improved athletic performance, serum erythropoietin levels, VO2max
      • Other studies show no significant difference
    • Artificial “altitude environments” have been created to simulate living high, including:
      • Nitrogen dilution apartments
      • Oxygen filtration apartments/tents
      • Training at altitude with the use of supplemental oxygen
  • LLTH Model (live low, train high)
    • Varies from other models in that the altitude/ hypoxic training period is smaller and more discrete
    • Hypoxia may be used during a resting state (IHE) or with exercise training (IHT)
    • Time is typically limited to 180 minutes or less
    • Hypoxia can be natural or artificial
    • Evidence for the benefit to exercise performance is limited
    • Likely helps with pre-acclimatization prior to competition at altitude
  • Optimal training strategy
    • Has yet to be totally delineated
    • Current best evidence states the recommendation for competing/participating in the high-altitude environment is to allow for adequate acclimatization over a period of weeks
  • (Editors note: this section needs to be organized)
    • Mixed altitude strategies (such as LHTL plus train high) appear to increase Hbmass, V˙O2max, and endurance performance greater than typical LHTL.
    • Absolute changes in Hbmass and V˙O2max do not necessarily translate into proportional changes in endurance performance.
    • Absolute changes in Hbmass and V˙O2max appear to be repeatable as a result of LHTL, but performance improvements are far more variable.
    • LHTL may induce additional nonhematological improvements that transfer into cycling performance improvement.
    • Enhancement of Hbmass as a result of LHTL may improve repeat maximal cycling performance.
    • In elite athletes, sedentary and confined living conditions as a result of living in an altitude house may not provide an adequate stimulus for enhanced erythropoietic activity, leading to a substantial increase in Hbmass.
    • Consideration of current training phase is required when implementing an altitude training program designed to enhance specific endurance performance determinants, in particular, running economy.