Week 8 - Heart Rate Variability and Cardiovascular Drift

• The pulse rate is not the only way of measuring the heart
• Stroke volume (SV)


  The amount of blood pumped out of the left ventricle per beat
• Cardiac output (Q)


  The amount of blood pumped out of the left ventricle of the heart per minute
• Calculating cardiac output


  Cardiac output (Q) = stroke volume (SV) × heart rate (HR)
• Cardiovascular drift


  Reduction of Stroke Volume (SV) and blood pressure, and an increase in heart rate after about 10 minutes of consistent sub maximal exercise
• As exercise remains at a steady state

  The body responds to an increase in body temperature by diverting fluid in blood plasma to the skin to cool the body down
• Decrease in blood volume during exercise and cardiovascular drift

  The viscosity of the blood increases
• Cardiovascular drift


  A person may feel like they are exerting more energy than they were before
• Cardiovascular drift


  • Can be reduced through consistent fluid and electrolyte replacement, as well as with training and acclimatisation to the exercising environment
• Heart Rate Variability (HRV)


  The different time between individual heartbeats
• Autonomic nervous system


  Responds to different internal and external environments, and the HRV is a measure of how well a person's body can quickly adapt to these small changes
• HRV


  • Determined by several features such as genetics, gender, and age, but it can also be increased through exercise
  • Highly trained athletes will both show a higher HRV and a quicker return to a resting heart rate and HRV after exercise
• More Fit = Higher HRV