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Continuous and Intermittent Exercise in Chronic Heart Failure Patients

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

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Continuous and Intermittent Exercise in Chronic Heart Failure Patients

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  1. Louisa Beale1, John Silberbauer2, Guy Lloyd2, Peter Watt1, Gary Brickley1 Continuous and Intermittent Exercise in Chronic Heart Failure Patients • Chelsea School Research Centre, University of Brighton, Eastbourne, East Sussex BN20 7SR • Eastbourne District General Hospital, Eastbourne, East Sussex BN21 2UD

  2. 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 HRmaxOR 40-60/70% HRR (Karvonen) • β-blockers: deduct 20-30 beats.min-1 from HRmax • RPE 11-14

  3. 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?

  4. Methods Patients: 10 (8 male 2 female) CHF (NYHA Class II-III) Mean ± SD Age (yr): 75 ± 8 Height (m): 1.74 ± 0.12 Body mass (kg): 85 ± 16 VO2 peak (ml.kg.min-1) : 15.4 ± 4.5 Medication: β-blockers n= 9, anti-arrhythmic n = 3 Exercise Tests: Maximal exercise test cycle ergometer ramp rate 10 W/min Measurements: Resp. gas exch., HR, BP, RPE .

  5. 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) EXERCISE DOMAIN 1 2 VO2 PEAK EXTREME SEVERE 90W RCP HEAVY Exercise Intensity (W) VT average workload 45W MODERATE 25W 20 REST Continuous Intermittent Time

  6. ResultsComparison of exercise data at VT with average values during CON and INT Mean ± SEM VT CON INT Average 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

  7. HR response to continuous and intermittent exercise in CHF patients and control subjects

  8. HR during continuous exercise @ 90% VT relative to BACR guidelines

  9. Peak HR and target HR ranges recorded during a maximal exercise test vs. predicted values 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

  10. 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

  11. Continuous and Intermittent Exercise in Chronic Heart Failure PatientsLouisa Beale1, John Silberbauer2, Guy Lloyd2, Peter Watt1, Gary Brickley11.Chelsea School Research Centre, University of Brighton, Eastbourne, BN20 7SR2. Eastbourne District General Hospital, Eastbourne BN21 2UD ANY QUESTIONS?

  12. Comparison of HR as % HRR, and VO2 as % VO2R at VT and during CON and INT

  13. Identifying Ventilatory Threshold

  14. Identifying RCP

  15. Identifying VT and RCP

  16. HR response to continuous and intermittent exercise in CHF patients and control subjects

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