Respiratory System PT2

Depth & rate of breathing increases TV increases by utilising both IRV & ERV Consequently IRV & ERV will decrease VE increases dramatically due to TV & freq of breathing increasing before exercise there’s slight rise (anticipatory rise) in ventilation caused by adrenaline

Sudden increase in ventilation begins to slow down & may plateau ❖ This is known as steady state ❖ Brain detects energy demands of muscles being met by o2 provided

Steady state doesn’t occur ❑ Ventilation continues to increase until exercise concludes ❑ RCC detects high levels of co2 & lactate with bodies need to expel these

Gases diffuse down a concentration gradient from area of high concentration to low • After breathing in, alveoli have high concentration of O2, blood capillaries have low concentration • Oxygen diffuses from alveoli into capillaries to even out concentration

Maximum volume of O2 than can be taken & used per minute per kg of bodyweight Measured in litres per minute per kg of body mass

GENDER: Women have lower VO2 max. Males hearts & lungs are larger Amount of blood an athlete’s heart can pump partially determines VO2 max BODY COMPOSITION: Research shows VO2 max decreases as body fat % increases Much of difference between male & female is body composition TRAINING: VO2 max can be improved by 10-20% following sustained & specific training ALTITUDE: Lower air pressure makes O2 less available Pressure of arterial blood also decreases, lowering VO2 max PHYSIOLOGY: Physiological make up of athletes body affects VO2 max % of slow twitch muscle fibres, capillary density, mitochondrial density & myoglobin levels AGE: Research has shown that VO2 max can decrease by 10% per decade after 30 BATGAP

Respiratory centre in brain detects increased levels of CO2 Nervous impulses received by internal, external, intercostals & diaphragm Increased rate of breathing & increased volume of thoracic activity Breath faster & deeper Minute Ventilation increases

Exercise leads to: Decreased O2 levels Increased CO2 & lactate levels Increased body temperature Increased muscular fatigue Breathing rate/depth increases (12-16/ min at rest). Endurance athletes can increase to 60/70/ min Gaseous exchange rate increase. Deliver more O2 & remove more CO2 Muscles facilitating breathing work harder to increase expansion of thoracic cavity during inspiration TV increases – RCC detects changes in O2 & CO2 levels ME increases – info picked up from receptors in muscles More CO2 removed to maintain concentration gradient & allow diffusion to occur BIG DIM TIM

Diaphragm, intercostal muscles exercised regularly & increase strength ▪ Improved utilization of alveoli – efficiency will improve ▪ Increased capillarisation surrounding alveoli – greater surface area for more gaseous exchange ▪ Greater efficiency of O2 uptake and general lung function occurs ▪ Reduction of O2 debt during exercise RIGID

Amount of O2 required to remove lactic acid & replace body’s reserves of O2

Unfit: Ventilation = 25 breaths per minute x 4 litres = 100 litres per min Fit: Ventilation = 18 breaths per minute x 6 litres = 108 litres per min