Environmental

• Altitude is the height above sea level (ASL).

  1500m ASL is when altitude starts to influence performance.

  2400m ASL is the optimum altitude to train for acclimatisation.

  Acclimatisation is where you gradually adapt physically to a change in the environment, usually a lower pp of oxygen.
• Immediate effects of altitude on the CV system

  1. Increased HR

  2. Decreased SV

  3. Decreased maximal CO

  4. Decreased plasma volume in the blood

  5. Decreased oxygen transport to the muscle from the blood

  6. Reduced haemoglobin saturation
• Immediate effects of altitude on the respiratory system

  1. Increased breathing rate

  2. Increased TV

  3. Decreased oxygen diffusion from alveoli to capillary blood (smaller diffusion gradient)

  4. Decreased pp of oxygen in inspired air entering alveoli
• Immediate effects of altitude on sporting performance

  1. Performance deteriorates in aerobic activities

  2. Earlier onset of fatigue

  3. Lower pp of oxygen in atmosphere

  4. Lower pp of oxygen in alveoli

  5. Lower rate of oxygen diffusion from alveoli to capillary blood (smaller pressure gradient)

  6. Decreased Hb oxygen saturation

  7. Decreased oxygen transport in blood to working muscles

  8. Decreased maximal CO

  9. Earlier onset of fatigue
• Physiological benefits of altitude training

  • Decreased altitude sickness
  • Increased release of EPO
  • Increased red blood cells and Hb
  • Increased oxygen carrying capacity of blood
  • Increased Hb oxygen concentration
  • Increased oxygen delivery to muscles
  • Increased surface area of alveoli
  • Increased TV and MV
  • Increased volume of mitochondria
  • Improved performance at aerobic activities
• Problems of altitude training

  • Increased altitude sickness
  • Dehydration
  • Expensive/not easily accessed
  • Benefits are quickly lost when returned to sea level (after 2 weeks)
  • Training is very hard due to lack of available oxygen
  • Increased lactate production
  • Decreased immune system
  • Timing acclimatisation is vital but difficult
• Timing of acclimatisation is important as:

  Different people acclimatise at different rates, allowing 3 weeks to acclimatise is ideal for a noticeable effect, important to avoid/recover from altitude sickness, if not long enough there is no benefit and detraining effects occur and if returning to compete at sea level physiological benefits wear off after 2 weeks.
• Other training types that have similar benefits to altitude training:

  Hypoxic tents/masks

  Intermittent hypoxia training

  ‘Live’ at sea level but train under hypoxic conditions (low pp of oxygen), body acclimatises gradually by living at altitude whilst training intensity can be maximised due to training where pp of oxygen is the same as at home.
• Normal body temperature

  37 degrees celsius, depending on the person, their age, what they've been doing and the time of the day
• Thermoregulation


  The process that allows the body to maintain its internal core temperature
• Thermoregulation process

  1. Thermoreceptors sense increase in core body temperature

  2. Blood vessels vasodilate

  3. Metabolic heat transported by circulating blood to body surface

  4. Heat released by evaporation (sweat) and convection

  5. Can lead to fluid loss which cools the body but can lead to dehydration if fluids aren't replaced

  6. Dehydration impairs body's ability to thermoregulate allowing core body temperature to rise

  7. Can affect performance as you could enter hyperthermia
• Hyperthermia

  An elevated body temperature where the body produces/absorbs more heat than it can get rid of, this can cause poor thermoregulation, high and prolonged exercise intensity, high air temperature and high relative humidity
• Heat on the CV system

  Blood flow redirected to skin for cooling purposes, limits blood flow to muscles and lowers venous return, cardiovascular drift can occur which is where blood plasma volume reduces due to an increase in water loss and blood viscosity, SV decreases, reduced oxygen transport to working muscles and increased strain on CV system
• Heat on the respiratory system

  Causes dry airways that result in - increased mucus production, constriction of airways, decreased volume of air for gas exchange. Breathing frequency increases to maintain oxygen consumption, high levels of sunlight that increase pollutants in air increasing irritation of airways, wheezing and coughing, asthma can be worsened
• Physiological effects of heat

  Increased oxygen cost of activity, decreased aerobic energy production, carbohydrate stores are used quicker, try to produce energy anaerobically, build up of lactic acid meaning fatigue occurs earlier and an increase in core body temperature affects the rate of chemical reactions
• Effect of heat on performance without acclimatisation

  Perceived exhaustion will feel worse, performance times are hindered in endurance events, strength endurance and aerobic capacity is reduced, exercise duration and intensity reduces, and maximal based activities aren't hindered
• Heat acclimatisation advice for people pre competition

  7 to 14 days in same conditions as competition in order to increase the body's tolerance to heat - Increasing plasma volume, increasing onset and rate of sweating, increasing efficiency of CO distribution and decrease the loss of electrolytes. Cooling aids can be used
• Heat acclimatisation advice for people during competition

  Wear suitable clothing that maximises heat loss, rehydrate often (hypotonic/isotonic solution) and pace yourself
• Heat acclimatisation advice for people post competition

  Use cooling aids to help return to core body temperature and rehydrate (hypotonic/isotonic solution)