ENVIRONMENTAL CONSIDERATIONS Altitude Acclimatisation

Altitude At altitudes of approx 1500m above sea level the ability to perform physical work is affected. The higher the altitude the more severe the effect.

Altitude Training programs can be undertaken in these climates as either preparation for competing at high altitude or in an attempt to establish benefits in preparation for competition in regions of lower altitude or at sea level.

Altitude Short-term anaerobic work is not affected by altitude, but longer tem aerobic performances are diminished. At altitude there is a reduced oxygen concentration in the air. Effect = volume of oxygen carried per litre of blood decreases.

Altitude Less oxygen abailable to fuel the body’s energy processes = more blood needed to deliver the same quantity of oxygen to the tissues = increase in heart rate.

Altitude

When exercising at altitude you must decrease the intensity due to lack of oxygen. Lower humidity and air temperatures at altitude also create temperature regulation problems in the body.

Altitude Benefits of altitude training Increased oxygen-carrying capacity of the blood. Reduced air resistance = better for throwing, jumping and sprinting events.

Altitude Question: What does this mean in terms of endurance / aerobic events at sea level?

Altitude If competing at high altitude, athletes will commonly spend a reasonable period of time at high altitude to acclimatise. Period ranges from 2-4 weeks..

Altitude Some employ “stop over” techniques. They arrive at high altitude as close as possible to the day of competition and leave straight after competing. They are then only exposed for a very short time = reducing the time and physical difficulties experienced with acclimatisation

Acclimatisation The lack of enough oxygen at altitude stimulates physiological adaptations that improve tolerance of the changed conditions – both at rest and during exercise. Process = acclimatisation.

Acclimatisation Immediate physiological responses: Increased ventilation – occurs within a few hours of arriving and stabilises after approx. 1 week. Increased cardiac output – heart beats faster, not more blood pumped out. Increased blood pressure.

Acclimatisation Longer term adjustments: Increased amount of red blood cells and haemoglobin. pH balance of body fluids. Changes to tissues and cells.

Acclimatisation The longer a person stays at altitude, the better the performance. Some people are unable to acclimatise = “mountain sickness”. They descend too quickly.

Acclimatisation Benefits of altitude training is lost 2-3 weeks after returning to sea level.

Acclimatisation Questions 1. Draw a chart showing the effect of altitude on heart rate and ventilation. Explain why these changes occur. 2. What effects would pollution have on performance?