acute exercise acute exercise –single bout of exercise steady state (submaximal) exercise ...

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?

HeartRate

Mile

Heart Rate and Acute Exercise


What causes heart rate to What causes heart rate to

increase?increase? ParasympatheticParasympathetic SympatheticSympathetic CatecholaminesCatecholamines

– EpinephrineEpinephrine– NorepinephrineNorepinephrine


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


Other formulas: Other formulas: 210 – (0.65 x age)210 – (0.65 x age) 208 – (0.70 x age) 208 – (0.70 x age)



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?


• 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?


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)

Stroke Volume and Acute ExerciseCardiovascular Drift

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?


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?


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 Pressure During Acute Exercise


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 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..


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


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

acute exercise acute exercise –single bout of exercise steady state (submaximal) exercise ...

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