KINE 433: Topic 9 Study Guide

What is the average RHR for adults?

60-80 bpm

What is HRV?

Heart Rate Variability: measure used to examine rhythmic fluctuation of heart

• Also known as changes in time intervals (called interbeat intervals; IBI) between heartbeats

What does HRV indicate and evaluate?

HRV indicates CV transient and chronic adaptability.

HRV evaluates contributions of ANS (sympathetic and parasympathetic) during resting and “activated” conditions.

What does a declining HRV score mean for athletes?

HRV has been recommended to indicate signs of overtraining syndrome in athletes

What are the four factors related to the acute changes of SV?

1. Afterload

2. Ventricular contractility

3. Ventricular distensibility

4. Volume of venous return

Define afterload and ventricular distensibility

Afterload: pressure the heart has to overcome in order to beat

Ventricular distensibility: heart’s ability to stretch

How does SV increase despite decreased time for filling during increased intensity exercise?

Higher SV during increasing intensity of training are increased preload and increased contractility

What are the four factors that increase SV?

• greater preload and EDV → Frank-Starling Mechanism

• increased sympathetic response → increased contractility

• increased ejection fraction = lower ESV

• decreased afterload

What is the Fick equation?

VO2 = HR x SV x (a-v) O2 difference

What are the two factors that O2 consumption is determined by?

O2 consumption is determined by extraction ((a-v) O2 diff) value and availability (cardiac output) of blood flow

What is responsible for the immediate increase in HR at the start of exercise (up to 100 bpm)?

During exercise, immediate increase in HR (up to 100 bpm) due to increasing vagal tone withdrawal

What further causes increases in HR as intensity increases?

As intensity increases and more Q is needed, HR increases due to sympathetic activation

What is the Valsalva maneuver?

Holding breath to increase intrathoracic pressure; creates rigidity

Valsalva maneuver — how long to hold it for, particularly for inexperienced athletes

Should only be held for ~2 seconds (in general)

Valsalva maneuver — what is it best used for in a training session

Allows athletes to support heavier loads, creates rigidity, increases BP

What are the five catalysts for muscular vasodilation?

1. Increased H+ → acidity

2. Decreased pH → acidity

3. Increased CO2

4. Increased temperature

5. Decreased PO2 → O2 levels dropping

With CV drift, what are considered to be the primary causes for it to occur?

Occurs with prolonged aerobic exercise, can occur in hot environments

• Decreased preload (EDV) due to % of Q directed to skin and decrease in plasma volume (via sweating and shift of plasma across capillary membrane into tissues → reduced venous return)

• Also, can be less filling time with higher HR

What happens to (a-v)O2 difference during exercise? What does it signify?

(a-v)O2 difference significantly increases during exercise

• signifies more O2 being extracted, which results in lower venous O2 content

Ventilation increases proportionally to exercise intensity. What causes increase in ventilation at low intensity? At high intensity?

Low intensity = increase in tidal volume (deeper)

High intensity = increase in tidal volume and respiration rate (deeper + faster)

What is Ventilatory Threshold (think O2 and VCO2)?

• Disproportional increase of ventilation to O2 consumption

• Disproportional increase of VCO2 production to O2 consumption

• Disproportionate increase in VCO2 will increase RER

Explain the difference between VT1 and VT2.

• VT1: Ventilation and VCO2 production increase. Increased VE is to “blow off” excess CO2.

• VT2: Rapid increase in lactate production vs. lactate clearance; increased hyperventilation

  • the point during incremental exercise that exponential increase in minute ventilation (VE) relative to VO2 (oxygen uptake) happens

VT1 and VT2 — Which shows the athletes ability to sustain higher intensity for long durations?

VT2 is seen as an indicator of an athlete’s ability to sustain higher intensity for longer duration

What is exercise-induced arterial hypoxemia and when is it most likely to occur?

At 95-100% of VO2 max, there is low oxygen saturation in the blood; at this intensity, blood is moving so fast through the lungs that it is not efficient in oxygenating

Possible limitation in elite marathon runners

When does lactate rise more quickly?

Lactate rises more quickly during anaerobic exercise

What is the best/quickest way to remove lactate posttraining and how long before it returns to baseline?

• Active recovery (ex. ~50% of VO2 max) clears lactate quicker than passive

• Lactate returns to resting levels ~2 hours