exercising in altitude Flashcards
altitude vs sea level
Altitude- Lower partial pressure of oxygen and lower barometric pressure
Sea – higher PO2 and higher barometric pressure
what is hypoxia
Less available oxygen that can be utilised by body @ sea level
what does hypoxia result in
- Results diminished supply O2 to tissues
- Rely on anaerobic system – early fatigue
- At altitude, there is a reduction in the pressure of O2 entering the lungs. This reduces the pressure difference with the result being less O2 diffusing from the alveoli into the blood
acute adaptations - respiratpry (3)
Respiratory issues
Decrease oxygen diffusion
- As altitude increases PO2 in air drops so doesn pressure gradient between o2 and lungs
- Less oxygen diffuses from lungs to blood
Decrease VO2 max
- Maximal O2 uptake begins decrease signifcantlly above altitude 1600m
Respiratory bodies reposnse
increase ventilation
- at rest and submaximal to increase oxygen uptake
acute adaptations - cardio
Cardiovascular issues
Decrease maximal cardiac output
- During exhaustive exercise at maximum levels both maximal stroke volume and maximal heart rate decrease with altitude.
- combined has significant effect on maximal cardiac output
cardiovascular bodies responses
increase HR and Q
decrease blood volume
- plasma volume decreases within first few hours of exposure
- increases the density of RBC
- the amount of haemoglobin per unit of blood is now increased (haematocrit) resulting greater O2 transport given Q
acute adaptations muscular/metabolic
tissue diffusion (muscular) - O2 passes from oxygen-rich arterial bllof reaches the active tusye via a pressure gradient - As this is decreased, less oxygen passes (diffuses) from the blood to the tissues. Increase conc of LA at any submaximal exercise intensity compared to sea level - Lack of oxygen availability and utilisation at altitude places a greater demand on anaerobic metabolism to produce energy.
issues with performing at altitude (4)
- Any athletic performance critically dependent on oxygen for metabolism, i.e., any event lasting longer than roughly two minutes, will experience performance decrements due to compromised aerobic energy production
- Performance in repeat sprint exercise is impaired at altitude due to the lower oxygen availability to replenish creatine phosphate stores and remove lactic acid
- A prolonged stay at altitude may result in a loss of body mass and reduced training capacity (eventually leading to detraining)
- ** However, performance in one-off sprint or power events may be enhanced at altitude due to low air resistance and drag**
altitude acclimatisation
Improved physiological response to altitude hypoxia
Athletes use altitude training to prepare for performance at altitude and improve performance at sea level
altitude acclimatisation - chronic adaptations (8)
- Erythroprotein (EPO) secretion by the kidneys increases (produces RBC)
- Increase production of RBC
- Increase haemoglobin conc as RBC contain haemoglobin
- Increase haematocrit (% RBC in blood) – due to a decrease in PV more O2 can be carried by blood to working muscles increase O2 delivery
- Increase capillarisation – increase transport 02
- Increase mitochondria – increase O2 utlisation and aerobic EP
- Increase aerobic enzymes – faster rate glycogen and fat breakdown
- Increase myglobin – increase extraction capability of the muscle cell
methods acclimatisation - live high train high
Used when preparing for comp altitude
- Gain adaptations both in and out of training/competition
- minimum of 2 weeks to ensure altitude sickness has subsided, and adaptations begin to occur
- Compromise in training intensity when at altitude
- Disruption to the training program
- aim is to improve performance at altitude
live low train high
train competition venue live at relative sea level/train in simulated altitude chambers
IMPROVING PERFORMANCE AT ALTITUDE
• Obtain adaptations to altitude exposure
• Prepares athletes physiologically and psychologically for the stress of hypoxic competition
• Adaptations not as effective as those gained via option 3 (live high train low), due to reduction of training intensity
HOW?
• Train at a higher altitude for at least 2 weeks prior to competition.
• full acclimatization to altitude takes 4 to 6 weeks, many of the physiological adaptations occur in the first 2 weeks
IMPROVING PERFORMANCE AT SEA LEVEL
• advantage as gain same relative training stimulus or ‘stress’ at a lower workload Assists in preventing overuse injuries.
• Also required to maintain adaptations from a pre-season altitude camp
• Might be beneficial for athletes who are returning from injury i.e. can use a stationary bike in an altitude chamber and get a significant exercise stress response but at a decreased load
live high train low
Daily exposure to artificial altitude environments outside of training
- Involves gaining long term chronic aerobic adaptations, by being exposed to either a simulated hypoxic environment (tents, hypobaric chambers, altitude chambers) NOT WHILST TRAINING
- Hypoxic apartments, altitude houses and tent used where the pressure of O2 in the air manipulated to simulate conditions at altitude.
- athlete continues their normal training at sea-level during the day whilst in the evening he/she spends a minimum of 12 hours sleeping or resting in a simulated altitude tent
- Enables benefits of altitude exposure whilst living/sleeping
- Training in sea level conditions ensures quality and intensity of the training session is optimised
returning to sea level after altitude
Within 7 days
Increased breathing rate not required at sea level as there is more oxygen available in the atmosphere at sea level.
After 2-4 weeks
Haemoglobin and haemotocrit levels back to normal
↑Mitochondria, capillary and enzyme levels thought to last longer provided training is maintained
considerations when preparing to compete in altitude
Increase recovery between sessions is required following exercise bouts at altitude.
An extended tapering period in the lead up to major competition is required to enable the athlete time to peak.
Training intensity at altitude must be decreased given the strenuous nature of the conditions.
A strict fluid replacement regime needs to be put in place as less humid conditions create a greater risk of dehydration.
