altitude

Altitude

As altitude increases, the pressure of the air decreases. The percentage of oxygen in the air remains the same but the pressure reduces. This has an effect on the partial pressure of oxygen arriving in the alveoli leading to:

• decreased saturation of haemoglobin

• Decreased O2 transport to muscles

• Reduced diffusion of O2 into muscle cells

 

Immediate impact of high altitude on body systems

• Increased Breathing Rate at rest and exercise

• Blood plasma volume decreases by up to 25% to increase density of red blood cells

• Stroke volume decreases which increases Heart Rate

• Maximum Cardiac Output decreases at high intensities

• Reduced metabolic processes in the muscle cell

 

Overall impact

• reduction in VO2 max leads to a reduction in aerobic capacity.

• Performance of endurance activities and training at altitude becomes much harder.

• Demands of the anaerobic energy systems increased.

• Early fatigue.

-> Results show that for every 1,000m above 1,500m VO2 max drops by around 8-11%

 

O2 availability

% O2 availability at altitude compared to sea level:

• at sea level = 100%

• Medium altitude at 1500m = 84%

• High altitude at 2400 = 76%

• Extreme altitude at 5500m = 52%

 

Days of training required for acclimatisation at different altitudes

• 1000-2,000m = 3-5 days

• 2,000-3000m = 2 weeks

• 3000m+ = 2+ weeks

Acclimatisation

process where the athlete gradually adapts to a change in their environment. This is essential for endurance athletes who rely on oxygen transport for effective performance.

 

Benefits of acclimatisation

• Release of EPO increases red blood cell production

• Increased O2 transport in the blood leads to improved O2 consumption in the muscle cell - increases aerobic endurance

• Breathing rate and ventilation stabilise - still remain elevated compared to sea level.

• Stroke volume and cardiac output reduce as O2 transport improves.

• Increased VO2 max as a result of improved O2 transport

• Lowered effects of altitude sickness e.g. nausea + dizziness