THE RELATIONSHIP BETWEEN YEAR THE RELATIONSHIP BETWEEN YEAR OF PROGRAM COMPLETION AND OF PROGRAM COMPLETION AND

FREQUENCY OF EXERCISE IN FREQUENCY OF EXERCISE IN CARDIAC REHABILITATION CARDIAC REHABILITATION

PATIENTSPATIENTS

Robert C. Lowe, MA, FAACVPR

Wellness Research Center

University of Central Florida

IntroductionIntroduction• We previously reported that physical

activity (PA) returned to near baseline by 6 and 12 mo. following an intensive cardiac risk intervention program (Lowe, et. al, 1998).

• In addition, there was a shift in exercise patterns (EP) from high to moderate intensities (Lowe & Williams, 2000).

• Both increased PA and EP have been implicated in the primary and secondary prevention of coronary artery disease (CAD).

PurposePurpose

The purpose of this study was to determine if the years since program completion (YEARS) influence frequency of “vigorous” aerobic exercise (FREQ).

Null HypothesisNull Hypothesis

YEARS since graduation will not influence the FREQ of “vigorous” physical activity.

MethodsMethods• Annual cardiac rehab survey yielding

731 responses between the years of 1994 – 1998.

• Variables of interest:• YEARS since program completion• FREQ of exercise per week

“In the past 3 months how often did you exercise aerobically for 20-30 minutes in your training heart rate zone per week?”

Subject CharacteristicsSubject Characteristics• Age, 62±11 yr.• Completed cardiac rehab program

• Exercise• Diet• Classes

• Average YEARS since completion of program, 4.3±2.3 yr.

• Average FREQ of 2.5±1.1 exercise sessions per week

StatisticsStatistics

• The relationship between FREQ and YEARS was explored by linear regression.

• Data was analyzed by one-way ANOVA and Sheffé post-hoc tests.

• The level of significance was set at p < 0.05.

ResultsResults

• The linear relationship between FREQ and YEARS was significant (F= 20.97, df=730, p < 0.05).

Prediction Equation

• FREQ = 2.16 + 0.167[YEARS]• Where YEARS = 1,2,3,4,5,6,7,8

ResultsResults

ANOVA

FREQ

38.605 7 5.515 4.470 .000

20.534 1 20.534 16.643 .000

26.027 1 26.027 21.095 .000

12.578 6 2.096 1.699 .118

892.021 723 1.234

930.627 730

(Combined)

Unweighted

Weighted

Deviation

Linear Term

BetweenGroups

Within Groups

Total

Sum ofSquares df Mean Square F Sig.

YEAR 1 2 3 4 5 6 7 8

FREQ 2.15a 2.37 2.67 2.56 2.37 2.74 2.62 2.85b

a different from YEARS 2-8; b different from YEARS 1-7

ResultsResults

124 9458109 93907093n

ResultsResults

TIME since completion

87654321

Me

an

of

FR

EQ

of

vig

oro

us

exe

rcis

e p

er

we

ek

3.0

2.8

2.6

2.4

2.2

2.0

ConclusionsConclusions

• The results indicated that YEARS since program completion significantly predicted FREQ.

• Further, FREQ was significantly greater 8 years post-cardiac rehab compared to 1 year post-cardiac rehab.

CaveatsCaveats

• Data is by self-report.• No information regarding diagnosis at

entry. • New medications, treatments,

diagnoses.• Seasonal fluctuations in PA• Did not construct the survey.• Not a random sample.

DiscussionDiscussion

• The amount and intensity of physical activity of this group of post-cardiac rehab patients is likely to be less than has been shown to reverse CAD.• 5 sessions x 30 minutes = 150 minutes per

week• On the average subjects performed 2.5

sessions x 30 minutes = 75 minutes per week

DiscussionDiscussion

• Lifestyle Heart Trial: 1990• Low fat diet: 10% Fat• Moderate exercise: > 30 minutes• Daily stress managementResults:• Treatment group showed 3.1% decreased

coronary blockage over 5 years versus 11.8% increased blockage in the control group

• Subjects who showed the most improvements exercised 5-7 hours per week

Ornish D, Brown SE, Lancet. 336: 129-133, 1990.

DiscussionDiscussion

Tests of Between-Subjects Effects

Dependent Variable: INTERVEN

35.541b 40 .889 2.265 .000 .117 90.616 1.000

3.316 1 3.316 8.456 .004 .012 8.456 .827

17.880 7 2.554 6.513 .000 .062 45.588 1.000

2.897 5 .579 1.477 .195 .011 7.387 .522

8.910 28 .318 .811 .744 .032 22.717 .756

268.272 684 .392

349.000 725

303.812 724

SourceCorrected Model

Intercept

GRAD

FREQ

GRAD * FREQ

Error

Total

Corrected Total

Type III Sumof Squares df Mean Square F Sig.

Partial EtaSquared

Noncent.Parameter

ObservedPower

a

Computed using alpha = .05a.

R Squared = .117 (Adjusted R Squared = .065)b.

DiscussionDiscussionRevascularization by PTCA or CAB

Years Since Completion

87654321

Estim

ate

d M

arg

ina

l M

ea

ns

1.4

1.2

1.0

.8

.6

.4

.2

0.0

-.2

Exercise FREQ

1

2

3

4

5

DiscussionDiscussion• It is recommended that future research

focus on interventions designed to increase PA.

““An Ounce of Prevention is An Ounce of Prevention is Worth a Pound of Cure." Worth a Pound of Cure."

--Benjamin FranklinBenjamin Franklin