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Louisa Beale 1 , John Silberbauer 2 , Guy Lloyd 2 , Peter Watt 1 , Gary Brickley 1. Continuous and Intermittent Exercise in Chronic Heart Failure Patients. Chelsea School Research Centre, University of Brighton, Eastbourne, East Sussex BN20 7SR - PowerPoint PPT Presentation
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Continuous and Intermittent Exercise in Chronic Heart Failure Patients
Louisa Beale1, John Silberbauer2, Guy Lloyd2, Peter Watt1, Gary Brickley1
1. Chelsea School Research Centre, University of Brighton, Eastbourne, East Sussex BN20 7SR
2. Eastbourne District General Hospital, Eastbourne, East Sussex BN21 2UD
Introduction: Exercise for Chronic Heart Failure (CHF) patients
Continuous (below VT) (Meyer (T), 2005; Gordon & Scott, 1995, Demopoulos, 1997)
• Similar physiological demands in individuals• Moderate and maintainable intensity• Above VT increases LV wall stress and decreases LV function
Intermittent (Interval) (Meyer (K), 1996 & 1997, Wisløff et al, 2007)
• Greater stimulus to the periphery without over-taxing weakened heart• Allows challenge to heart’s pumping capacity• Greater improvements than after continuous training
BACR guidelines• 60-75/80 % predicted HRmax OR 40-60/70% HRR (Karvonen)• β-blockers: deduct 20-30 beats.min-1 from HRmax
• RPE 11-14
Aim
To compare exercise training intensities derived from cardiopulmonary exercise testing with current exercise prescription guidelines in CHF
• What are the acute responses to continuous (CON) and intermittent (INT) exercise at an intensity equivalent to 90% VT?
• Are current BACR guidelines likely to prescribe an exercise intensity at or below VT?
Methods
Patients: 10 (8 male 2 female) CHF (NYHA Class II-III)
Mean ± SDAge (yr): 75 ± 8Height (m): 1.74 ± 0.12Body mass (kg): 85 ± 16VO2 peak (ml.kg.min-1) : 15.4 ± 4.5 Medication: β-blockers n= 9, anti-arrhythmic
n = 3
Exercise Tests: Maximal exercise testcycle ergometerramp rate 10 W/min
Measurements: Resp. gas exch., HR, BP, RPE
.
2 x 20 min exercise bouts, 1 week apart, randomised, equal work doneContinuous: 90% VTIntermittent: work phase 110% RCP: 30s (x 13) recovery phase: 60s (x14)
REST
VT
RCP
VO2
PEAK
Exe
rcis
e In
tens
ity (W
)
Continuous Intermittent
45W
20
averageworkload
MODERATE
HEAVY
SEVERE
EXTREME
90W
25W
Time
EXERCISE DOMAIN1 2
Results
Comparison of exercise data at VT with average values during CON and INT
Mean ± SEM
VT CON INTAverage HR (beats.min-1) 80 ± 3 78 ± 3 77 ± 3
Average VO2 (ml.min-1) 810 ± 98 859 ± 86 869 ± 83
METS 3.0 ± 0.8 3.0 ± 0.7 3.1 ± 0.5
RPE 11.7 ± 0.9 12.1 ± 0.6
RPP* 101 ± 5 98 ± 5
* BP(mm.Hg-1) x HR (beats.min-1)/100
No significant differences were found
HR response to continuous and intermittent exercise in CHF patients and control subjects
HR during continuous exercise @ 90% VT relative to BACR guidelines
Peak HR and target HR ranges recorded during a maximal exercise test vs. predicted values
Recorded Predicted p value Maximum heart rate (beats. min-1) 105 ± 5 118 ± 4 * 0.02 Heart rate reserve (beats. min-1) 48 ± 5 61 ± 5 * 0.02 60% maximum heart rate (beats. min-1) 63 ± 3 71 ± 2 * 0.02 80% maximum heart rate (beats. min-1) 84 ± 4 94 ± 3 * 0.02 40% heart rate reserve (beats. min-1) 76 ± 3 81 ± 2 * ** 0.02 0.00 70% heart rate reserve (beats. min-1) 90 ± 4 99 ± 2 * ** 0.02 0.00
* p< 0.05: difference between recorded and predicted values
** p< 0.05: difference between % maximum or peak HR and %HRR methods
Recorded Predicted
HRmax (beats.min-1) 105 ± 5 118 ± 4 *HRR (beats.min-1) 48 ± 5 61 ± 5 *60% HRmax (beats.min-1) 63 ± 3 71 ± 2 *
40% HRR (beats.min-1) 76 ± 3 81 ± 2 * 80% HRmax (beats.min-1) 84 ± 4 94 ± 3 * **70% HRR (beats.min-1) 90 ± 4 99 ± 2 * **
*p< 0.05: difference between recorded and predicted values**p< 0.05: difference between % HRmax and %HRR methods
Practical Implications
• Exercise at or just below VT is well-tolerated, and intermittent is an alternative to continuous (next study will investigate continuous vs. intermittent at a higher intensity)
• Difficulty of accurate exercise prescription in CHF patients without CPET
• Don’t rely on % predicted HRmax to guide exercise intensity
• 40-70% HRR does not correspond with 60-80% HRmax
• HRR (Karvonen) method is likely to prescribe exercise at or above RCP, i.e. heavy exercise domain
Continuous and Intermittent Exercise in Chronic Heart Failure Patients
Louisa Beale1, John Silberbauer2, Guy Lloyd2, Peter Watt1, Gary Brickley1
1.Chelsea School Research Centre, University of Brighton, Eastbourne, BN20 7SR2. Eastbourne District General Hospital, Eastbourne BN21 2UD
ANY QUESTIONS?
Comparison of HR as % HRR, and VO2 as % VO2R at VT and during CON and INT
Identifying Ventilatory Threshold
Identifying RCP
Identifying VT and RCP
HR response to continuous and intermittent exercise in CHF patients and control subjects
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