PE 34 chapter 5

acute respiratory responses

• increased respiratory rate

• increased tidal volume

• increased ventilation

• increased gaseous exchange

respiratory rate

• How many breaths per minute.

• 12-15 breaths per minute during rest, but rate will increase as a direct response to the oxygen demand. A warmup leads to a gradual increase, can rise to 50-60 breaths per minute.

• Direct linear relationship between exercise intensity and respiratory rate and oxygen uptake

Tidal volume

• The amount of air taken per breath.

• At rest tends to be 0.5L, in exercise can rise to 4-5L. Males have higher TV due to larger lungs.

• TV has a finite capacity, reached at submax intensities. Max TV at 75% HR.

Ventilation

• Air breathed in and out from lungs per min.

• Ventilation (L/Min) = respiratory rate (breaths/min) x tidal volume (L/breath)

increased gaseous exchange

• Takes place at lungs and muscle. Gas moves from high to low concentration. As we breath in, more o2 enters the lungs and more difusion in alveoli due to surrounding capillaries.

• Carbon dioxide concentration is higher in capillaries then alveoli, o2 goes into capillary and carbon moves out = gas exchange.

• Difusion from the lungs will reach the muscles, once blood is used carbon produced. Breathing out gets carbon out of body, gases are exchanged.

• Allows so oxygen can go through working muscles while difusing with carbon dioxide, from high to low pressure.

Acute cardiovascular responses

• increased heart rate

• increased stroke volume

• increased blood pressure

• redistribution of blood

• increased cardiac output

oxygen uptake

refers to the amount of oxygen transported to, taken up by and used by the body for energy production.

oxygen uptake at rest

• approximately 0.25/0.3 litres per minute

• The body stores minimal amounts of oxygen. This means that the amount of oxygen entering your bloodstream is directly proportional to the amount used by your tissues for oxidative metabolism.

• demand for oxygen

• low HR

• low RR

• low muscle activity

• o2 supply= o2 demand

maximum oxygen uptake (vo2 max)

the maximum amount of oxygen per minute that can be taken in, transported and utilised by the body for energy production

no further increase in oxygen uptake can be achieved

oxygen deficit

• the state in which there is a discrepancy (shortfall) between oxygen supply and the oxygen needed to meet the energy requirements of the activity. The anaerobic pathways must supplement the energy demands of the activity.

• start of exercise

• O2 demand is greater than the supplied O2

• during O2 deficit muscles obtain energy from anaerobic energy systems

• increase exercise intensity= increase oxygen deficit= longer for body to meet o2 demand

graph of o2 deficit, steady state and EPOC

EPOC

• excess post-exercise oxygen consumption

• elevated oxygen consumption after the completion of exercise

• after the completion of exercise o2 uptake or consumption does not immeadiately return to resting levels

• increase exercise intensity= larger EPOC

• larger deficit= larger EPOC

• active recivery increases EPOC

2 parts of EPOC

• fast part- restores ATP at muscles, restores o2 to myoglobin, re-synthesise CP

• slow part- core temp returns, HR and RR return, lactic converts to glycogen, glucose and protein, fatty acid cycling increases, accumulated h+ oxidisr into H2O and CO2

factors associated with the amount and duration of EPOC

• elevated muscle temp

• increased use of mitochondria

• increased ATP production

• restoring CP stores

• Lactate production during exercise