Exercise Physiology

how does exercise increase cardiovascular event

Plaque rupture from shear stress, structural heart disease exacerbation, arrhythmia can be triggered

What group of people are at risk for exercise related cardiovascular events

Known or silent CAD, sudden vigorous activity, non regular exercise → Suddenly exercise

What is 1 MET

Energy burned at rest; 30-38 calories for every 30 minutes; equal to VO2 at rest

What is VO2 max

Max rate of O2 consumption possible during physical exertion; represent aerobic capacity and a strong predictor for mortality and longevity

How do you measure VO2 max

Direct → Inspire/expire gas analysis; Indirect → Look at peak EtCO2 or HR 90% max

What substrates are used during exercise

Glycogen, fat (slow exercise), Protein (increase when glycogen low esp in fasting)

What is crossover concept

When body adapts to prolonged exercise body switches from using carbs to fat

What is lactate threshold

Point where blood lactate accumulates faster than clear → Marks point of anaerobic respiration

What adjustments occur in skeletal muscle during exercise

CO increases (mostly from HR) ; blood is directed to muscle from inactive muscle

How does blood flow and resistance change in exercise

Blood flow increases by decreasing resistance

How does the body maintain high blood flow in muscle during exercise

Metabolic vasodilation; myogenic response to cause vasodilation; eNOS → NO → vasodilation; conducted vasodilation; temperature rise

What is angiogenesis

Creation of capillaries; found in exercise in order to increase delivery of O2 and nutrients

How does VR change in exercise

Sympathetic stimulation cause vasoconstriction → Stress blood volume increase → MSFP increase → VR increase; hyperventilation → RA pressure decrease → MSFP-RA gradient increase → VR increase

how does muscle change in exercise

Enhanced muscular endurance → Myoglobin and MT size and number increase; capillary density increase; higher level of fatty acid oxidative enzymes

How does lung physiology change in response to exercise

Increase ventilation and perfusion to keep PaCO2 and PaO2 same; pH rises (alkalosis)

How does the respiratory system adapt during exercise

There can be respiratory muscle fatigue → O2 deficit → Steady state where O2 is used and can be delivered → Early EPOC → Lact acid replenishment

What happens in early EPOC

O2 fast replenishment to restore AP and creatine phosphate

Why you you have abdominal pain after exercise

There is less blood going to GI → Mild ischemia

What is a-vO2 difference

Indicates effectiveness of muscle to extract oxygen from arterial blood

What is Fick equation

Used to determine O2 consumption; VO2 = CO x (CaO2 - CvO2)

How do you induce erythrocythemia

Increase the amount of Hb in blood → More O2 → Increased performance

What happens during isometric exercise

SBP and DBP rise sharply → Stroke volume changes little in contrast to increased resistance

What happens during isotonic exercise

CO is increased (proportional to O2 consumption), VO2 max increase

What is the difference between isokinetic and cardio

Isokinetic → Constant speed and resistance; cardio is aerobic for fitness and mental/cognitive function

What is HIIT

Exercise that swaps between rounds of high intensity and low intensity exercise

What is heart rate zone

Intensity measured with %VO2 max, % max HR, RPE, lactate threshold; 1-2 (light) to lose weight; 3-4 improve fitness; 4-5 (most intense) for athletic training

What is RPE

Measures the intensity of exercise from 0-10

What is fat burning zone

Fat is burned less with high intensity exercise → Between 50-72% of VO2 max

What is CTE

Compromise in adaptation from concurrent training (doing both resistance and endurance training will cause muscle loss)

What does resistance training do

Activate mTOR-Raptor-S6K I pathway that regulate muscle growth

What is the difference between casein and phosphocreatine protein powders

Caseins: Digested more slowly → Reduce appetite and increase fullness; phosphocreatine → Increased strength (produces ATP) → Increase muscle volume

How does increasing temperature help in exercise

1C increase in temperature can improve performance by 2-5%

What is delayed muscle soreness

Soreness that is felt most strongly 24-72 hours after exercise

What is the mechanism behind exertional heat stroke

Hyperthermia → CNS dysfunction, vasodilation → Venous pooling → Hypotension and cardiogenic shock