cardiovascular system

• Cardiovascular system


  • Made up of: heart + blood + blood vessels (arteries and veins)
  • Responsible circulation of blood and oxygen around the body
• When we begin exercising

  The cardiovascular system will initiate acute responses to INCREASE THE CIRCULATION OF BLOOD
• Cardiovascular system - acute responses

  • Heart rate (HR)

  ⭐: the number of times the heart beats in one minute

  • Stroke volume (SV)

  ⭐: amount of blood ejected from the left ventricle each beat

  • Cardiac output (Q)

  ⭐: amount of  blood is pumped from the heart  in one minute (Q = HR x SV)

  Exercise starts  -> ↑ cardiac output  -> ↑ O2 transport
• Resting:

  HR & SV & Q are all at resting levels + lower overall

  
  

  Submaximal exercise: 

  SV and HR increase proportionally with each other -> increases Q 

  
  

  High intensity exercise: 

  Any increases in Q are due to ↑ HR until maximum heart rate is reached
• Increased venous return (↑)

  ⭐: flow of blood back to the heart

  • Can increase via:
  • The muscle pump
  • The respiratory pump
  • Vasodilation 
• Redistribution of blood flow

  • When exercising, blood is redistributed from non-essential organs to working muscles
  • Vasodilation of the arteries to the muscles
  • Vasoconstriction of the arteries that deliver blood to the digestive system and organs 

  *redistribution is proportional to exercise intensity
• Decreased blood volume (↓) - aerobic exercise 

  • Plasma in the blood is lost from sweating during aerobic exercise to maintain homeostasis
  • During anaerobic exercise, blood volume remains relatively unchanged (don’t sweat much as the duration is short)
• Increased blood pressure (↑)

  • Systolic (↑)

  ⭐: the pressure recorded as blood is ejected during the contraction phase (exercise) - increases as exercising

  • Diastolic (~)

  ⭐: the pressure recorded during the relaxation phase of the heart cycle (relaxation) - relatively unchanged during exercise