EP - Cardiovascular Correlates of Exercise Practical

Question 1

Describe blood pressure during exercise:

Answer 1

Blood pressure (BP) = Cardiac Output (CO) × Total Peripheral Resistance (TPR)

During exercise, changes in BP reflect the integrated response of the heart, vessels, and skeletal muscle.

Question 2

Describe blood pressure during dynamic (Isotonic) exercise:

Answer 2

Systolic BP:
- Increases linearly with exercise intensity due to rising CO
- Typical peak values: 160–220 mmHg in healthy adults at max effort

Diastolic BP:
- Stays the same or may decrease slightly (due to vasodilation in active skeletal muscle → ↓ TPR)
- Reflects effective peripheral vasodilation and redistribution of blood flow

Mean Arterial Pressure - Increases modestly (~10–20 mmHg), ensuring adequate perfusion pressure

Baroreceptor resetting allows for increased BP without reflex bradycardia
Muscle metaboreflex and central command increase sympathetic drive

Question 3

Describe BP During Static (Isometric) Exercise:

Answer 3

Systolic and Diastolic BP both rise significantly:

• Unlike dynamic exercise, there is sustained muscle contraction → compresses blood vessels → ↑ TPR
• DBP may rise as much as SBP → MAP increases sharply

Mechanisms:
- Mechanical compression of arteries impedes flow → reflex sympathetic activation
- Muscle metaboreflex stimulates vasoconstriction and ↑ HR → maintains perfusion

Question 4

Describe the US Army Harvard Step test and its advantages and disadvantages:

Answer 4

A classic submaximal exercise test developed in the 1940s to assess cardiovascular fitness and recovery

Procedure:
- Step up and down a 20-inch (men) or 16-inch (women) bench at 30 steps/min for 5 minutes or until exhaustion
- Pulse rates are taken 1–1.5 minutes after completion.
- Fitness index = (Duration of exercise in seconds × 100) / (Sum of recovery heart rates × 2)

Advantages:
- Simple, portable, and low-cost; no expensive equipment needed
- easy to administer in large groups
- Provides an estimate of cardiovascular recovery efficiency
- Submaximal → generally safe for low-risk individuals

Disadvantages:
- Not accurate for individuals with poor leg strength, balance, or coordination
- Step height not adjusted for height/fitness → may skew results
- Relies on subjective effort; less valid than VO₂ max tests
- Poorly suited for clinical populations, elderly, or those with cardiovascular conditions

Question 5

describe the effects of incremental exercise on blood pressure:

Answer 5

As exercise intensity increases;
- SBP rises linearly with workload, due to increasing CO
- DBP remains stable or slightly decreases, depending on vascular compliance and muscle perfusion

Beyond ~70% VO₂max, BP plateaus or increases more steeply due to:

• Increased sympathetic tone
• Rising catecholamine levels
• Higher motor unit recruitment