# 2. Ex Psy week 6

version from 2018-04-09 11:29

## Section 1

How were marathon performance be affected by altitude decreased performance, as aerobic discipline and rely on oxygen in air. increased altitude = decreased oxygen.
How would 200m sprints or long jump performance be affected by altitudeincreased performance. Anaerobic discipline so don't rely on oxygen. Decreased oxygen in the air, means the air is less dense so there is less resistance to run against.
What changes the most at high altitude (Mt. Everest) compared to sea level.Barometric pressure. Changes from 760 mmHg to 253 mmHG. About 3 fold decrease. Partial pressure (molecules in air) also decreases 3 fold. 159 to 53.
What doesn't change at high altitude (Mt. Everest) compared to sea level.%02 in the air. Stays at 20.93
What is Boyle's Lawat a constant temperature, the volume of a gas is inversely proportional to its pressure
What happens to the pressure at altitudeless pressure, (less pressure from air above) therefore air can expand and molecules can be further apart.
Describe the oxygen transport cascade at sea level PO2 around 100mmHg enters the blood, When it reaches the muscles there is a PO2 of 40mmHg, so a diffusion gradient of 60mmHg
Describe the oxygen transport cascade at 4,300m compared to sea levelLower PO2 of around 42mmHg enters the blood. This time there is a lower partial pressure of oxygen in the muscles of around 26mmHg so that the oxygen can still diffuse, but the diffusion gradient is still lower at 15mmHg, so less oxygen is available.
What is the ventilatory response to graded exercise at altitude• Increased ventilatory drive at altitude (less oxygen available so have to increase breathing rate to get the oxygen in)• Decreased maximum capacity at altitude (oxygen uptake, power output)

## Section 2

Maximum oxygen uptake and marathon performance at altitude100% of V02max is reached at sea level, but this decreases as altitude increases. at 6000m it halves. Therefore, even at the same intensity or speed, becomes a higher fraction of there VO2 max, working harder to achieve same intensity.. therefore marathon times increase.
Describe oxygen consumption/uptake at sea level VS high altitude, expressed as absolute unit or relative to the maximum At high altitude (4300m) V02 max decreases. (for example from 4.0L/min, to 2.7). Therefor when working at the same workout, they have a similar absolute VO2 (say around 2.0 L/min)but this is a different %of there V02 max. May be only 50% at sea level but 70% at high altitude.
What VO2max would you need at sea level to climb Mt Everest without supplemental oxygenat least 50ml/kg/min. As comparing sea level and everest Vo2 max and inspired PO2 it decreases 3 fold. So would need a VO2max of at least 50 ml/kg/min to maintain a walking VO2max at the summit of everest.
One positive adaptation from altitude trainingincrease in red blood cells. EPO increase.
One negative adaptation from altitude trainingloss of muscle mass.
What is Erythropoietin (EPO)• is a hormone • is secreted mainly from kidney cells in response to reduced O2 delivery • stimulates erythropoiesis (erythrocyte, or red blood cell production) in the bone marrow • results in increased number of red blood cells
What is acclimatisation - Hb concentrations for residents at various altitudesTakes into account big time frames. (exposure of years). Increased altitude = increased Hb concentrations (due to constant stimulus).
What is respiratory alkalosis and role of the kidneys in acid-base readjustment. Pulmonary ventilation (increased breathing rate at altitude removes H+ and HCO3- from the blood --> Washout of C02. Therefore as we are getting rid of protons (H+) we are causing a more alkaline environment. We also get rid of bicarbonate, the kidneys excrete HCO3- to restore normal pH, but therefore reducing the blood buffering capacity, which could be an issue at higher intensities.

## Section 3

Acute adaptations to altitude: Blood and Plasma. Plasma volume decreases within a few hours, due to respiratory water loss and increased urine production (caused by a decreased in anti-diuretic hormone and decreased renin/aldosterone). This causes a loss of up to 25% in plasma volume and a short term increase in haematocrit.
Chronic adaptations to altitude; Blood and PlasmaHypoxaemia triggers EPO release from kidneys, this causes RBC productions in the bone marrow to increase. Long-term increase in haematocrit.
Acute adaptations; cardiac responses. – Submaximal heart rate ↑ – Submaximal cardiac output ↑
Chronic adaptations; cardiac resposnes– Submaximal heart rate ↑ therefore volume loading of heart ↓ and stroke volume ↓  – Maximal heart rate ↓ (wont reach max, due to increased parasympathetic tone) therefore can decrease maximal cardiac output!
chronic adaptations; muscular adaptations• Muscle function and structure changes – Capillary density ↑ – Muscle mass loss, possibly protein wasting  Cross-sectional area decreases. And Muscle metabolic potential can be affected – Mitochondrial function and glycolytic enzymes ↓ causing Oxidative capacity to decrease.
To increase Hb concentrations takes weeks to months (look at graphs pg 20)
maximum responses effect of VO2max and cardiac output over time at altitudenegative- cardiac output drops, a lot at start but then increases, but still less than at sea level.
What is acclimationprolonged exposure to altitude to get people used to the altitude, increase there performance at that altitude (but may never match that at sea level).
How long does acclimation take Takes 3-6 weeks at moderate altitude (2-3,000 m) – Add 1 week for every additional 600 m – Lost within 1 month at sea level
What does living high and training high lead to dehydration, low blood volume and low muscle mass
What are the 2 strategies for sea-level athletes who must sometime compete at altitude. 1. Compete ASAP after arriving at altitude • Does not confer benefits of acclimation • Too soon for adverse effects of altitude 2. Train high for 2 weeks before competing • Worst adverse effects of altitude over • Aerobic training at altitude not as effective
Why do some studies find that many highly trained athletes show no major cardiovascular adaptations/improvements in sea level performance after living and training at altitude Possible causes: – Already attained maximal adaptations? – Hypoxia at altitude prevents high-intensity aerobic training ( remember training principles: periodisation - volume, intensity… or also progressive overload!)
at what altitudes should you live and train at to optimise training and performance.• Live high, train low: best of both worlds – Permits passive acclimation to altitude – Training intensity not compromised by low PO2
effects of living high and training low for 27 days over a 3000m time trialif you are not elite trained, you tend to benefit more from altitude training.
Key principles of altitude training • Elevation must be high enough to raise EPO to increase total red blood cell volume and Vሶ O2max • Training must take place at an elevation low enough to maintain training intensity at nearsea-level values
What are the alternative to the mountains artificial environment, such as altitude chamber.
Environmental conditions at altitude; air temp– Temperature decreases 1°C per 150 m ascent – Contributes to risk of cold-related disorders
Environmental conditions at altitude; humidity – Cold air holds very little water – Dry air  quick dehydration via skin and lungs  Air at altitude is cold and dry