UOW SHS221 - Cardiovascular Physiology Notes PDF

Preview

Summary

Summary for SHS221 divided into topics - detailed, comprehensive and organised notes covering content from lectures, tutorials, textbooks and further research. Simple, easy-to-read format for easy reference and study....

Description

Types%of%Exercise% ! Terms% % Acute:%single!bout!of!exertion!which!requires!energy!expenditure!above!resting! Chronic:!repeated!bouts!of!exertion!requiring!energy!expenditure!above!resting! Adaptation:!the!modification!of!a!physiological!system!due!to!exposure!to!acute!or!chronic!exercise! ! Maximal:% • Highest!possible!energy!expenditure!achievable,!greatest!load!or!longest!duration!able!to!be!achieved! • Difficult!and!rarely!achieved! • Must!test!numerous!times!to!ensure!a!maximal!response!has!been!achieved!(eg.!VO2!max)! Peak:% • The!heist!energy!expenditure,!load!or!duration!achieved!in!an!exercise!bout! • Most!commonly!achieved!(eg.!VO2!peak)! Submaximal:% • An!exercise!stimulus!or!physiological!response!that!is!below!the!peak!or!maximal!response!achievable! Steady3state:% • An!exercise!stimulus!that!elicits!a!relative!plateau!(flattening)!in!the!physiological!response! Incremental%or%step3wise:% • An!exercise!stimulus!that!increases!or!decreases!in!steps! Ramp:% • Continuous!small!changes!in!workload! !

Plateau!means!physiological!systems!are!meeting!workload.!

!

! Lengths%and%types%of%exercise% …result!in!varied!physiological!responses!due!to!intensity,!duration!or!modulation!of!physical!activity.! ! Short3term%moderate%submaximal%exercise:!10K15!minutes,!30K69%!of!maximal!work!capacity! Long3term%moderate%to%heavy%submaximal%exercise:!>30!minutes,!55K89%!of!maximal!work!capacity! ! Incremental%aerobic%exercise%to%maximum:% • Commencement!at!lighter!loads!which!increase!consistently!at!a!predetermined!rate!until!volitional!exhaustion! • Don’t!reach!a!steady!state!at!each!step!to!ensure!max!work!is!achieved!without!early!fatigue! • To!reach!steady!state!in!an!incremental!protocol,!steps!need!to!be!prolonged! Static%exercise:% • Muscle!activation!which!produces!elevated!muscle!tension!and!energy!expenditure!but!which!does!not!produce! significant!movement! Dynamic%resistance%exercise:! • Consecutive!development!of!muscle!tension!against!a!resistance!that!produces!movement!(with!a!proportional! cardiovascular!response)! ! % % SHS221%Exercise%Physiology%3%1%

Exercise%intensity%3%workload% • Absolute:! §฀ A!defined!workrate!or!distance,!oxygen!consumption!or!physiological!response! §฀ Example:!100!watts,!1000m,!3.0!L/min,!100!kg!(not!relative!to!the!person)! • Relative:! §฀ An!absolute!value!is!expressed!related!to!another!variable! §฀ Example:!60ml/kg/min! §฀ Known!as!normalisation! §฀ Allows!comparison!across!populations! §฀ Used!commonly!in!research!to!standardise!exercise!stimuli,!permitting!similar!intensities!of!exercise! despite!differing!absolute!loads! §฀ Example:!70%!of!VO2!peak!in!trained!person!may!be!300!watts!and!in!untrained!person!may!be!100!watts! ! External%Work% NOTE:!there!needs!to!be! • Work!=!Force!(ma)!x!displacement!(s)! displacement!for!external! §฀ Units:!joules!(1!joule!=!1!Nm)! work!to!occur!(but!internal! §฀ Example:!lift!5kg!upward!over!a!vertical!distance!of!2m! work!can!still!occur).!! Work! =!5!x!9.81!(gravity)!x!2! External!work!does!not!equal! ! =!98.1!Nm!(or!joules)! internal!work!! • Power!=!(force!x!displacement)/time! §฀ Units:!watts!(Nm/sec!or!Joules/sec! §฀ Example:!lift!5kg!upward!over!a!vertical!distance!of!2m!for!2!seconds! Power! =!(5!x!9.81!(gravity)!x!2)!/!2! ! =!49.05!watt! ! Internal%Work/Energy%Expenditure% • Approximately!20K25%!of!all!energy!expended!is!used!to!produce!external!work! • 78K80%!is!heat!–!so!heat!is!an!excellent!marker!to!use!as!a!measure!of!energy!expenditure!or!internal!work! ! Measuring%internal%work:% • Direct!calorimetry:! §฀ Expensive! §฀ Errors!may!be!produced!during!exercise!as!the!ergometer!will!produce! heat! • Indirect!calorimetry!(openKcircuit!indirect!spirometry):! §฀ Does!not!involve!the!direct!measurement!of!heat! §฀ Direct!relationship!exists!between!O2!consumption!and!heat!production! §฀ VO2!max!test! K Absolute!value:!L/min! K Relative!value:!mL/kg/min!(choosing!this!expression!means!you!think! weight!affects!the!oxygen!consumption!–!eg.!cycling!up!a!hill!because! the!cyclist!has!to!move!their!body!weight!up!the!hill)! ! ! ! !

SHS221%Exercise%Physiology%3%2%

Cardiovascular%responses%to%exercise% ! The%Fick%Principle% ! VO2%=%HR%x%SV%x%AVO2diff% % ! ! ! Or! ! VO2!=!Q!x!AVO2diff!

% !

HR!x!SV!–!central!level% AVO2diff!–!muscle!level!

AVO2diff:!arteriovenous!oxygen!difference!(the!difference!between!the!amount! of!oxygen!entering!and!leaving!the!muscle!or!the!amount!of!oxygen!extracted! by!the!muscle)!

! Stroke!Volume!=!left!ventricle!EDV!–!ESV! (how!much!blood!coming!out!per!contraction)! ! VO2%max:% • Finite!rate!of!maximal!oxygen!transport!to!support!ATP!production! • Measure!of!exercise!performance! • Marker!of!CV!disease! • Absolute!functional!capacity! • ↓!VO2!max,!↑!risk!of!mortality!(four!fold!increase!in!risk!of!mortality!with!a!VO2!max!...