Acute exerciseAcute exercise– Single bout of exerciseSingle bout of exercise
Steady State (Submaximal) exerciseSteady State (Submaximal) exercise Maximal exerciseMaximal exercise
Chronic exerciseChronic exercise– Months of conditioning or trainingMonths of conditioning or training– Differences between training and Differences between training and
untrained individualsuntrained individuals
EXERCISE AND THE HEARTEXERCISE AND THE HEART
Cardiovascular Response to Acute Exercise
Blood flow (and distribution)….
All of the above change during exercise in order to meet the increase O2 and energy demands of the muscles.
Heart rate (HR), stroke volume (SV), and cardiac output (Q)...
.
Blood pressure …
Heart Rate and Acute Heart Rate and Acute ExerciseExercise
Why does heart rate increase during Why does heart rate increase during acute exercise?acute exercise?
What causes heart rate exercise?What causes heart rate exercise? Why does heart rate level off when the Why does heart rate level off when the
exercise intensity levels off?exercise intensity levels off? What is the relationship between heart What is the relationship between heart
and exercise intensity? and exercise intensity? How is maximum heart rate estimated?How is maximum heart rate estimated?
Heart Rate and Acute Heart Rate and Acute ExerciseExercise
What causes heart rate to What causes heart rate to
increase?increase? ParasympatheticParasympathetic SympatheticSympathetic CatecholaminesCatecholamines
– EpinephrineEpinephrine– NorepinephrineNorepinephrine
Heart Rate and Acute Heart Rate and Acute ExerciseExercise
Why does heart rate level off when Why does heart rate level off when the exercise intensity levels off?the exercise intensity levels off?
O2 supply = O2 demandO2 supply = O2 demand
Heart Rate and Acute Maximal Exercise
What is the relationship
between heart rate and exercise
intensity? Or, how is heart affected by
the intensity of exercise?
Heart Rate and Acute Maximal Exercise
Can be Can be estimatedestimated: : HRmax = 220 – age in HRmax = 220 – age in yearsyears
– For 20 year old, HRmax For 20 year old, HRmax = 200= 200
– For 43 year old, HRmax For 43 year old, HRmax = 177= 177
Other formulas: Other formulas: 210 – (0.65 x age)210 – (0.65 x age) 208 – (0.70 x age) 208 – (0.70 x age)
– For 20 year old, HRmax For 20 year old, HRmax = 194= 194
– For 43 year old, HRmax For 43 year old, HRmax = 178= 178
202 – (0.72 x age)202 – (0.72 x age)
Stroke Volume and Acute Stroke Volume and Acute ExerciseExercise
Why does stroke volume increase during Why does stroke volume increase during exercise?exercise?
What causes stroke volume to increase What causes stroke volume to increase during exercise?during exercise?
Why does stroke volume stop increasing, or Why does stroke volume stop increasing, or reach its maximum, before a person reaches reach its maximum, before a person reaches their maximal effort?their maximal effort?
What is cardiovascular drift?What is cardiovascular drift?
Stroke Volume and Acute Stroke Volume and Acute ExerciseExercise
• What causes stroke volume to increase What causes stroke volume to increase during exercise? Hint: There is less residual during exercise? Hint: There is less residual volumevolume• What is residual volume?What is residual volume?• The amount of blood remaining in the heart after The amount of blood remaining in the heart after
a contraction. Also called end systolic volumea contraction. Also called end systolic volume• What causes the heart to beat stronger (and What causes the heart to beat stronger (and
thus reduce the residual volume) during thus reduce the residual volume) during acute exercise? acute exercise?
• Increase sympathetic stimulation and Increase sympathetic stimulation and increases in epinephrine and norepinephrineincreases in epinephrine and norepinephrine
Stroke Volume and Acute Maximal Stroke Volume and Acute Maximal ExerciseExercise
Why does stroke volume stop
increasing, or reach its
maximum, before a person reaches
their maximal effort?
Stroke Volume and Acute Stroke Volume and Acute ExerciseExercise
What is cardiovascular drift?What is cardiovascular drift? What happens to the amount of plasma What happens to the amount of plasma
as exercise continues? Increase or as exercise continues? Increase or decrease?decrease?
What affect would a decrease in plasma What affect would a decrease in plasma volume have on stroke volume?volume have on stroke volume?
If stroke volume decreases, what would If stroke volume decreases, what would have to happen to heart rate in order to have to happen to heart rate in order to keep blood flow or cardiac output at the keep blood flow or cardiac output at the same level? same level? (see next slide)(see next slide)
Cardiac Output and Acute Exercise
If heart rate and stroke volume If heart rate and stroke volume increase during exercise, what will increase during exercise, what will happen to cardiac output?happen to cardiac output?
Why is it important that cardiac Why is it important that cardiac output increases during exercise? output increases during exercise?
How can even more blood be sent to How can even more blood be sent to the exercising muscles? the exercising muscles?
Cardiac Output and Acute Maximal ExerciseIf heart rate and stroke volume increase during exercise, what If heart rate and stroke volume increase during exercise, what will happen to cardiac output?will happen to cardiac output?
Why is it Why is it important that important that cardiac output cardiac output increases increases during during exercise?exercise?
Summary of HR, SV and Q During Acute Exercise
Resting (supine) 55 95 5.2
Resting (standing 60 70 4.2 and sitting)
Running 190 130 24.7
Cycling 185 120 22.2
Swimming 170 135 22.9
Heart rate Stroke volume Cardiac outputActivity (beats/min) (ml/beat) (L/min)
Blood Flow and Acute ExerciseBlood Flow and Acute Exercise
How can even more blood be sent to How can even more blood be sent to the exercising muscles?.the exercising muscles?.
Blood Flow and Acute Blood Flow and Acute ExerciseExercise
How can even more blood be sent to How can even more blood be sent to the exercising muscles?the exercising muscles?
VasodilationVasodilation of arterioles near of arterioles near exercising musclesexercising muscles– Waste productsWaste products
VasoconstrictionVasoconstriction of arterioles near of arterioles near non-exercising muscles and organs.non-exercising muscles and organs.– Sympathetic stimulationSympathetic stimulation
Blood Pressure During Acute Blood Pressure During Acute ExerciseExercise
How would an increase in blood flow How would an increase in blood flow through the blood vessels affect through the blood vessels affect blood pressure?blood pressure?
How would vasodilation of the blood How would vasodilation of the blood vessels affect blood pressure?vessels affect blood pressure?
Blood Pressure During Acute Blood Pressure During Acute ExerciseExercise
Cardiovascular Endurance ExerciseCardiovascular Endurance Exercise
What affect does CV exercise have What affect does CV exercise have on on systolicsystolic blood pressure? blood pressure?
Why?Why? What affect does CV exercise have What affect does CV exercise have
on on diastolicdiastolic blood pressure? blood pressure? Why?Why?
Blood Pressure During Acute Blood Pressure During Acute ExerciseExercise
Resistance ExerciseResistance Exercise
How does resistance exercise How does resistance exercise affect blood pressure?affect blood pressure?
Why? Why? Some BP increases are attributed Some BP increases are attributed
to the Valsalva maneuverto the Valsalva maneuver
Blood Flow and Acute Blood Flow and Acute ExerciseExercise
What is responsible for the increase blood What is responsible for the increase blood flow to the muscles during exercise?flow to the muscles during exercise?– Increased cardiac outputIncreased cardiac output
Increased heart rate and stroke volumeIncreased heart rate and stroke volume– Redistribution of blood flowRedistribution of blood flow
Vasodilation and vasoconstrictionVasodilation and vasoconstriction What will happen to aerobic energy What will happen to aerobic energy
production as more blood is supplied to production as more blood is supplied to the muscles during exercisethe muscles during exercise
How is aerobic energy production How is aerobic energy production measured?measured?
Oxygen consumption or VO2Oxygen consumption or VO2
Oxygen ConsumptionOxygen Consumption
VO2 is a measure of how much and how VO2 is a measure of how much and how fast O2 is used to make energy (ATP)fast O2 is used to make energy (ATP)
In order for VO2 to increase what must In order for VO2 to increase what must change inside the body?change inside the body?
1.1. Increase cardiac outputIncrease cardiac output
2.2. Increase extraction of oxygen from the Increase extraction of oxygen from the bloodblood
Therefore VO2 = cardiac output x the Therefore VO2 = cardiac output x the amount of oxygen extracted from the amount of oxygen extracted from the bloodblood
Oxygen ConsumptionOxygen Consumption
Oxygen Extraction at Oxygen Extraction at RestRest
ArteriesArteries– 20 ml or oxygen in every 20 ml or oxygen in every
100 ml of arterial blood100 ml of arterial blood VeinsVeins
– 15 ml/100 ml of blood.15 ml/100 ml of blood. How much oxygen did How much oxygen did
the muscles use?the muscles use? This amount is call the This amount is call the
a-vO2 a-vO2 differencedifference..
Oxygen ConsumptionOxygen Consumption
Cardiac output (Q) = how quickly an Cardiac output (Q) = how quickly an amount of blood (e.g. 100 ml) flows to the amount of blood (e.g. 100 ml) flows to the musclesmuscles
a-v O2 difference = amount oxygen of that a-v O2 difference = amount oxygen of that 100 ml is extracted (or removed) from the 100 ml is extracted (or removed) from the bloodblood
VO2 = Q x a-v O2 differenceVO2 = Q x a-v O2 difference VO2 is how aerobic energy production is VO2 is how aerobic energy production is
measuredmeasured
Oxygen ConsumptionOxygen Consumption
What does VO2 tell us?What does VO2 tell us? How much oxygen is being used to make How much oxygen is being used to make
energyenergy Resting VO2 = 3.5 ml/kg/minResting VO2 = 3.5 ml/kg/min Exercise VO2Exercise VO2 Maximal VO2 (VO2 max)Maximal VO2 (VO2 max)
Exercise VO2Exercise VO2
Jogging = 24 ml/kg/min
Walking = 16 ml/kg/min
Running = 38 ml/kg/min
Sprinting= 57 ml/kg/min
VO
2 (
ml/kg
/min
)
Time
Maximal VO2Maximal VO2
TIME HR VO2 VO2/KG VCO2 R VE %EO2 %ECO21 125 2096 35.52 1577 0.75 37.70 15.78 4.202 138 2383 40.39 2000 0.84 45.30 15.97 4.453 140 2611 44.26 2295 0.88 51.70 16.13 4.474 147 2735 46.35 2333 0.85 53.70 15.88 4.585 155 2957 50.12 2677 0.91 58.70 16.10 4.616 164 3257 55.20 2934 0.90 62.30 15.92 4.767 168 3270 55.42 3041 0.93 63.90 16.00 4.818 174 3583 60.74 3481 0.97 76.00 16.36 4.639 180 3813 64.63 3848 1.01 85.50 16.58 4.5610 186 3999 67.77 4245 1.06 92.50 16.68 4.6511 192 4181 67.86 4704 1.13 111.60 17.17 4.29
Results from a graded treadmill test where treadmill speed and elevation are increased every minute.
Maximal VO2 ValuesMaximal VO2 ValuesPERCENTILEPERCENTILE 20-2920-29 30-3930-39 40-4940-49 50-5950-59 60+60+
MenMen
9090 51.451.4 50.450.4 48.248.2 45.345.3 42.542.5
5050 42.542.5 41.041.0 38.138.1 35.235.2 31.831.8
1010 34.534.5 32.532.5 30.930.9 28.028.0 23.123.1
WomenWomen
9090 44.244.2 41.041.0 39.539.5 35.235.2 35.235.2
5050 35.235.2 33.833.8 30.930.9 28.228.2 25.825.8
1010 28.428.4 26.526.5 25.125.1 22.322.3 20.820.8
►Average values for 18-22 year olds: 44 to 50 ml · kg-1 · min-1 for males and 38 to 42 ml · kg-1 · min-1 for females