Paper 1 - Environmental Factors

Question 1

What is altitude?

Answer 1

The height or elevation of an area above Sea Level
As altitude increases barometric pressure decreases (air pressure decreases)

Question 2

What is barometric pressure?

Answer 2

The pressure exerted by the earth’s atmosphere at any given point
As Altitude increases Barometric Pressure decreases (air pressure decreases) THEREFORE the partial pressure of oxygen decreases (even though it still remains at 20.9%)

Question 3

How does Altitude effect our intake of Oxygen?

Answer 3

As the Barometric Pressure decreases with increasing altitude, the partial pressure of oxygen also decreases. This effects the diffusion of oxygen into the blood because there is a smaller difference in pO2 gradient between the atmosphere and deoxygenated blood. Therefore it is harder for the oxygen molecules to cross the alveolar membrane and get into the bloodstream to be able to deliver oxygen to muscle cells.

In June 2007 FIFA raised the limit from 2,500 metres (8,200 ft) to 3,000 metres (9,800 ft), meaning that the only capital city affected by the ban would be La Paz. (Hernando Siles Stadium, La Paz, Bolivia) (Altitude - 3,600m)

Question 4

What are the effects of altitude?

Answer 4

Increased:
Breathing rate - breathing frequency increases at rest & exercise to try maintain oxygen consumption

Decreased:
Blood volume - plasma volume decreases by up to 25% to increase density of red blood cells, to maximise oxygen transportation
Stroke volume - within first few hours of altitude SV decreases during sub-max exercise which increases HR to maintain/slightly raise Q
Maximal Q, SV & HR - decrease with altitude during maximum intensity exercise
Aerobic Capacity & VO2 max - reduce impacting both intensity and duration of performance

Question 5

Steps that take place at altitude

Answer 5

Decreased pO2 in alveolar air
Decreased diffusion gradient to the capillary blood
Decreased haemoglobin and O2 association in the bloodstream
Decreased O2 transportation to the muscle tissue
Decreased O2 supply for aerobic energy production
Increases breathing frequency, decreases blood volume, SV and increased HR
Decreases VO2 max, aerobic capacity, intensity and duration of aerobic performance before fatigue

Question 6

What is acclimatisation?

Answer 6

The process of an athlete gradually adapting to a change in the environment.
E.g. low po2 at altitude (hypoxic environment)

Question 7

What is a hypoxic environment?

Answer 7

Reduced oxygen/lack of oxygen environment

Question 8

What are the benefits of acclimatisation for the cardiovascular and respiratory systems

Answer 8

Increases:
Release of EPO - EPO increases within 3 hours of altitude exposure, peaking 24-48 hrs later, increasing RBC production (with 6 weeks exposure to 4640m altitude, concentration of RBCs can increase by 14%)
Red blood cells - more RBCs = more haemoglobin = more oxygen carrying capacity in the blood
Capillarisation - more capillaries surrounding alveoli & muscle (more O2 diffusion)
Respiratory muscle strength - thoracic cavity become larger = increased TV (tidal volume) and VE (minute ventilation)
Number of alveoli - larger surface area of alveoli = more gas exchange

Stabilised:
Breathing rate - breathing rate and ventilation stabilise, however remain slightly elevated at rest and during exercise when compared with sea level

Acclimatisation reduces incidences of altitude sickness, headaches, breathlessness, poor sleep and lack of appetite

Question 9

What is erythropoietin (EPO)?

Answer 9

A naturally produced hormone responsible for the production of red blood cells

Question 10

What are the acclimatisation periods at different heights?

Answer 10

Altitude begins to have effects at around 1500m

Low : 1000-2000 (3-5 days)
Moderate : 2000-3000 (1-2 weeks)
High : 3000+ (2+ weeks)
Extreme : 5000-5500 (4+ weeks)

Question 11

Acclimatisation timing of arrival before performances

Answer 11

2/3 weeks prior to performance
- train at lower altitudes of 1500-3000 for min two weeks
- allows body time to adapt to hypoxic air environment

4/6 weeks prior to performance
- for full/ideal acclimatisation
- essential at extreme altitudes (4000+m)
- gradual ascent to performance altitude (days at lower levels)
- avoids altitude sickness
- altitude sickness drugs (acetazolamide/dexamethasone)

Question 12

Acclimatisation: what training option is best?

Answer 12

Live high train low is most effective option
Living high = long term adaptations beneficial to performance
-Ipincreased number/surface area of alveoli & increased alveoli/muscle capillarisation
-increased EPO/RBCs/Hb = increased O2 transport = increased diffusion at alveoli/muscles
-increases strength respiratory muscles = increased lung volume/TV/VE

Training Low = adequate O2 availability = no detraining effect = intensity/quality of training maintained = maximum adaptations to training

Question 13

Define thermoregulation

Answer 13

The process of maintaining internal temperature

Question 14

Define thermoreceptors

Answer 14

Sense a change in temperature and relay information to the brain

Question 15

Define hyperthermia

Answer 15

Significantly raised core body temperature (hypothermia = cold)

Question 16

Define dehydration

Answer 16

Loss of water in body tissues and blood, leads to the inability to control temperature

Question 17

Steps body goes through in heat

Answer 17

1. Increase blood/internal temperature
2. Impulse sent to hypothalamus
3. Increase vasodilation of skin arterioles
4. Increase sweat glands/evaporation
5. Decreased blood/internal temperature (back to 37)

Question 18

Effects of heat on the CV system (2 defence mechanisms)

Answer 18

The hypothalamus activates two defence mechanisms
Evaporative techniques (sweating)
Non-evaporative techniques (cooling of blood at the skin/vasodilation)

Question 19

Effects of heat on cv system : evaporative techniques

Answer 19

The hypothalamus stimulates the sweat glands.
Increased sweat production.
Sweat evaporates from the skin to provide cooling.
Decreased volume of blood plasma (less blood volume)
Less blood returns to heart (VR) = Reduced SV (Starlings law). Blood pressure also drops
HR increases to maintain O2 delivery to muscles.
Leading to cardiovascular drift (a decrease in SV causes an increase in HR).

Question 20

Effects of heat on cv system : non-evaporative techniques

Answer 20

Increased volume of blood to the skin.
Redistribution of blood to the skin from the muscles and organs.
Vasodilation of arterioles and pre-capillary sphincters at the surface of the skin.
Blood pooling at the skin occurs.
Causing a decrease in venous return (VR).
According to Starling’s law of the heart, if VR decreases, SV decreases.
Less blood to deliver O2 to the muscles.
HR increases to maintain Q and maintain O2 delivery to muscles.
Leading to cardiovascular drift

Question 21

Effects of heat on the respiratory system

Answer 21

Drying of the airways = constriction of airways = less air for gas exchange.
Increased mucus production to moisten airways = reduced air flow
Increased breathing frequency to maintain exercise intensity = increased energy ‘cost’ of exercise.

Question 22

Effects of heat on performance + stats

Answer 22

Decreased efficiency of CV and respiratory systems leads to Thermal strain which means that it is likely an athlete will move towards anaerobic energy production leading to OBLA and earlier fatigue
Maximal and explosive strength activities are unaffected by heat or may gain a slight advantage (due to lower air density)
Endurance sports are most affected by the rise in HR and breathing rate causing fatigue

Stats
Increases in temperature will have the biggest effect on endurance sports.
Wet-bulb globe temperature (WBGT) gives a measure of air temp, sun heat, humidity and wind speed.
At 10 oC a 3 hour marathon runner may add 3% to their time (approx. 5min 30sec)
At 25 oC it will be up to 12% (approx. 21min 30sec)
Hyperthermia can be reached at high WBGT temperatures

Question 23

Effects of heat on performance (dehydration)

Answer 23

Graph in heat lesson on Showbie

Exercise increases metabolic rate increasing heat production and increasing sweating
2% body weight water loos sufficient to increase temp and impairs performance by 10%
4-5% decrease performance by 20-30%. Most significant in low/moderate intensity high duration aerobic based activities (e.g 5000m, cycling team games : hockey/football)

Question 24

Heat stress disorders

Answer 24

If temperature cannot be controlled it can lead to heat stress disorders
Heat cramp - Due to dehydration and loss of electrolytes
Heat stroke - Second only to head/spine injuries as No.1 cause of death in athletes. Symptoms include cramps, muscle pain. This leads to heat exhaustion
CV system is unable to meet the demands of muscles and skin due to loss of blood volume through sweating, therefore can’t cool down or exercise.
Symptoms include sickness, dizziness, breathlessness, high HR, numbness in hands and feet. Can lead to death or permanent damage to brain/organs if body unable to reduce body temp.

Question 25

Acclimatisation to heat

Answer 25

3-5 days heat tolerance improves
- a decrease in core body temperature
- an increase in blood plasma volume
- a decrease in HR

2 weeks full acclimatisation occurs
- an increase in sweat rate
- an increase in evaporative techniques without electrolyte loss

Question 26

Strategies for competing in heat

Answer 26

Pre - Comp
Acclimatisation (7-14 days)
Ice vests - use cooling aid to decrease core body temp and decrease sweating

During - Comp
Using pacing strategies to reduce exertion
Wear suitable clothing that maximises heat loss (e,g, dry fit)
Rehydrate to replace fluids and electrolytes

Post - Comp
Cooling aids - cold towels and cold fans
Rehydrate to replace fluids and electrolytes