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 ± 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
2 x 20 min exercise bouts, 1 week apart, randomised, equal work done
Continuous: 90% VT
Intermittent: work phase 110% RCP: 30s (x 13) recovery phase: 60s (x14)
EXERCISE DOMAIN
Exercise Intensity (W)
1
2
EXTREME
VO2
PEAK
90W
SEVERE
RCP
HEAVY
VT
average
workload
45W
MODERATE
25W
20
REST
Continuous
Intermittent
Time
Results
Comparison 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
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
HRmax (beats.min-1)
HRR (beats.min-1)
-1)
60% HRmax (beats.min
Recorded
Predicted
-1
Maximum
heart rate
(beats. min(beats.min
)
105 ± 5
± 4
40%
HRR
)118
Heart rate reserve (beats. min )
48
± 5
61
± 5
60% maximum heart rate (beats. min ) 63
± 3
71
± 2
-1
80%
maximum heart
rate (beats. min
) 84
± 4
94) ± 3
80%
HR
(beats.min
max
40% heart rate reserve (beats. min )
76
± 3
81
± 2
70% heart rate reserve (beats. min )
90
± 4
99
± 2
70% HRR (beats.min-1)
-1
-1
-1
-1
-1
-1
Recorded
Predicted
105 ± 5
48 ± 5
63 ±p value
3
* 76 ±
0.023
*
0.02
*
0.02
* 84 ±
0.024
* **
0.02 0.00
* **
0.02 0.00
90 ± 4
118 ± 4
61 ± 5
71 ± 2
81 ± 2
94 ± 3
99 ± 2
*
*
*
*
* **
* **
* p< 0.05: difference between recorded and predicted values
** p< 0.05: difference between % maximum or peak HR and %HRR methods
*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 7SR
2. 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