Physiological Effects of Exercise Flashcards
(47 cards)
MET Level = Light Intensity
less than 3 METs
MET Level = Moderate Intensity
3-6 METs
MET Level = Vigorous Intensity
> 6 METs`
Recommended Physical Activity
Moderate intensity aerobic (endurance) physical activity for a minimum of 30 minutes a week, 5 days a week
OR
Vigorous intensity aerobic (endurance) physical activity for 20 minutes three days a week
Cardiac Output Equation
Heart rate x Stroke Volume
Systole
contraction phase; ejects 2/3 blood in ventricles
Diastole
Relaxation phase; during exercise, an increase in HR due to a decreased time in diastole
Distribution of Blood Flow During Exercise
arterioles dilate to allow blood to flow to areas that need it (muscles) and arterioles constrict to viscera not active; veins force blood in the extremities back towards the heart, while one way valves prevent backflow of blood; vasodilation reduces total peripheral resistance
Factors Influencing Stroke Volume
improved venous return (increased EDV-more stretch), sympathetic NS, contraction strength(the more that comes in, the more that goes out)
Factors Influencing Heart Rate
sympathetic nervous system
Pulse Pressure
Systolic- diastolic pressure
Mean Arterial Pressure
diastolic + 1/3 (pulse pressure); the perfusion pressure in the internal organs; must be above 60 to sustain organs
Blood Pressure during Arm v. Leg exercises
Arm exercises lead to higher SBP/DBP than leg exercises at the same percentage of VO2 max
Pulmonary Ventilation
V = Vt (tidal volume) x f (breathing frequency); the amount of air moved in and out of the lungs per minute
Control of Ventilation
respiratory control center receives neural and humoral input from the muscles (feedback from sensory info) and from CO2 levels in the blood; regulates respiratory rate
Ventilatory Control (Graph)
peripheral chemoreceptors and skeletal muscle receptors send info to the respiratory control center, which sends info to the midbrain, which then sends info to the respiratory muscles
Chemoreceptors
receive input from PP of CO2 and H+ in the carotid and aortic arch and send sensory impulses to the respiratory control center in the medulla
How much does oxygen demand of the muscle increase during heave exercise?
15-25%
How does the body respond to exercise to enable working muscles to get the oxygen rich blood they need?
mass discharge of sympathetic nervous system; increased arterial BP, increased CO; vasodilation in active mm;
How does the body regulate venous return of blood from the working skeletal muscles back to the heart?
skeletal muscle pump; vasoconstriction of blood vessels returning blood; one way valves keep blood from falling back
Normal SBP response?
for every MET increase, SBP should increase by 10 +/- 2 mmHg
When NOT to exercise (HR, SBP, DBP, O2)
HR >120 or 200mmHg or 110 mmHg
O2 Sats
When NOT to exercise- symptoms
unstable angina (chest pain), mental confusion, leg pain at rest (could be a blocked artery), cyanosis, increasing SOB, severe fatigue; acute illness
When to STOP Exercise
Decrease or stable heart rate with increased load; SBP >220 or decrease >10 during activity; DBP >110 or +/- 10 over baseline; O2 stats
