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Cardiovascular Exercise Intensity

PHYE 280: Exercise Physiology

Kevin Petti, Ph.D.Departments of Natural Sciences,

Health, Exercise Science and NutritionSan Diego Miramar College

Objectives

ω Understand the four main approaches ofmonitoring cardiovascular training intensity

ω Identify cardiac adaptations and healthrelated benefits to cardiovascular fitness

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Components of Fitness

ω Cardiorespiratory Enduranceν Ability of heart, lungs and blood vessels to deliver O2 to exercising

muscles

ω Muscular Strengthν Maximum amount of force a muscle can exert during a single

contraction

ω Flexibilityν Range of Movement (ROM) at a joint

ω Body Compositionν High lean mass or fat-free mass (muscle and bone)ν Low fat mass

Training For Cardiovascular Fitness

ω FITT Principleν Frequency

λ 3-5 days/week

ν Intensityλ Heart rate is best indicatorλ Discussed in the following slides

ν Timeλ 30 - 45 minutes

ν Typeλ Rhythmic, continuous activityλ Running, cycling, swimming, dancing

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Monitoring Exercise Intensity

ω Below are the primary methodsν Heart Rate

λ Percentage of maximal heart rate

λ Percentage of heart rate reserve

ν Rating of Perceived Exertion (RPE)λ Borg Scale

λ Category Ratio Scale (revised Borg Scale)

ν The “Talk-test” Method

ν METs

Percentage of Maximal Heart Rate

ω THR zone forindividual of 20 yrs.

ω MHR = 200 220-ageω 200 x .6 = 120ω 200 x .9 = 180ω THR zone =

120 to 180 bpmω For most untrained adults, low

intensity - high duration is bestω 120 bpm for 45 minutes or 180

bpm for 30 minutes?

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Percentage of Heart Rate Reserve

ω Karvonen Formulaν Considers RHR, an indicator of fitness level

THR = (MHR* - RHR) x desired intensity + RHR*MHR = 220 - age

Calculate for a 40 year old, w/ 80 bpm RHR at 70% intensity

THR = (180 - 80) x .7 + 80

THR = (100) x .7 + 80

THR = 70 + 80

THR = 150 bpm

Rating of Perceived Exertion

ω Exercise intensity measured by subjective feelings ofexertion

ω A scale of either 6 - 20 or 0 - 10ω Borg Scale (6 - 20):

ν 12 - 13 = 55 - 69% MHR, or 74% heart rate reserveν 16 = 90% MHR, or 85% HRRν Thus exercise between 12 - 16 is recommended

ω On Revised Borg or Category Ratio Scale (0-10):ν Intensity between 4 - 6 is recommended

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RPE Scales

ω Borg Scale (RPE)67 Very, very light89 Very light1011 Fairly light1213 Somewhat hard1415 Hard1617 Very hard1819 Very, very hard20

ω Category Ratio Scale revised Borg

0 Nothing at all.5 very, very weak1 Very weak2 Weak3 Moderate4 Somewhat strong5 Strong67 Very strong8910 Very, very strong* Maximal

The Talk-test Method

ω Also subjective method of determiningexercise intensity

ω Probably best for those just beginningexercise programs

ω Clients should be able to breathe comfortablyand maintain a conversation

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Intensity Measured by METs

ω One MET equals O2 uptake at restω Graded exercise testing can determine resting and maximal

O2 consumption, and express this in METsω Exercise intensity is prescribed as a percentage of maximal

METs (50-85%)ω Requires accurate determination of the MET equivalent for

an activityω Heart rate and RPE are probably more accurate and

convenient methods

Benefits of Cardiovascular Training

ω More favorable body compositionν Increases caloric expenditure and decreases appetite

ω Strengthens muscles and bonesν Reduces risk for osteoporosis

ω Reduces risk/controls Type 2 Diabetesω Reduces risk for Coronary Artery Disease

ν Controls hypertensionν More favorable blood chemistry

λ Decreases total cholesterol, increases good cholesterol (HDL)