Exercise Flashcards
What factors ensure that blood pressure is not static within an individual?
It is affected by activity, meals, stress, and medication. There is also a morning surge in blood pressure.
How does systolic and diastolic blood pressure change during acute dynamic exercise?
Systolic blood pressure increases with intensity, while diastolic blood pressure remains relatively unchanged.
How does oxygen consumption change during exercise?
Oxygen consumption increases until VO2max is reached.
What happens to the percentage of cardiac output received by most organs during heavy exercise?
Most organs maintain the same percentage of cardiac output, except for skeletal muscle, which receives proportionally greater cariac output during exercise.
Why can an excessive rise in blood pressure during exercise be a better indicator of cardiovascular health than resting blood pressure?
It is associated with higher early mortality rates and may indicate underlying cardiovascular issues.
What are the two main reflexes controlling blood pressure during exercise?
The metaboreflex and the mechanoreflex.
What is the role of the metaboreflex in blood pressure control during exercise?
It is the main controller of blood pressure during exercise. Chemoreceptors are activated by increased ATP and decreased pH (increased carbon dioxide), leading to increased sympathetic activity.
What is the role of the mechanoreflex in blood pressure control during exercise?
Mechanoreceptors detect physical distortion of muscle during exercise, increasing sympathetic nerve activity, leading to increased heart rate, contractility, stroke volume, and vasoconstriction in arterioles.
How can the mechanoreflex be isolated for study?
By using passive exercise, where movement occurs without requiring force from the participant.
How can the metaboreflex be isolated for study?
Through post-exercise ischemia: A handgrip exercise is performed, then a cuff is inflated above systolic blood pressure to trap metabolites in the forearm, and blood pressure is measured for 5 minutes.
What is sympatholysis, and why does it occur?
Sympatholysis is the vasodilation of skeletal muscle during exercise. It occurs because exercise-produced substances (e.g., nitric oxide) block the effects of sympathetic nerve activity in those areas.
Is the baroreflex switched off during exercise?
No, the brain shifts the baroreceptor reflex to recognize a higher blood pressure as necessary to maintain adequate blood flow.
What can cause baroreceptor failure?
Radiotherapy on the neck can lead to baroreceptor failure, significantly impacting daily activities.
How do people with hypertension respond to exercise compared to healthy individuals?
They experience a greater increase in blood pressure during exercise, even if their resting blood pressure is controlled with medication.
Why is the metaboreflex a potential target for hypertension treatment?
People with hypertension have high metaboreflex sensitivity, which may contribute to excessive blood pressure rises during exercise.
