Article

AIM: To verify the usefulness of current recommended level of target exercise
heart rate (HR) and of different HR-based methods for calculating target HR in
patients with and without beta-blocker treatment. METHODS:
We studied 53 patients
not treated with beta-blocker and 159 patients on beta-blocker treatment. All
patients underwent a maximal exercise test with gas analysis, and first
ventilatory threshold (VT1 or aerobic threshold), second ventilatory threshold
(VT2 or anaerobic threshold), time of exercise, maximum load, metabolic
parameters, HR at rest (HRrest), HRpeak, HR at VT1 (HRVT1) and at VT2 (HRVT2),
and 75, 80, and 85% of HRmax (HR75%, HR80%, HR85%) were calculated. Exercise HR
was also determined using the Karvonen formula, applying 60,
70, and 80% of the
heart rate reserve (HRR) (HRKarv0.6, HRKarv0.7, and HRKarv0.8). RESULTS: This
study included 102 patients on a beta-blocker and 39 not treated with negative
cronotropic effect drugs. Maximum load, metabolic parameters, HRrest, HRpeak,
HRVT1, and HRVT2 were significantly lower in patients on beta-blocker treatment.
The proportion of patients with a HR75%, HR80%, HR85%, HRKarv0.6, HRKarv0.7, and
HRKarv0.8 VT2 was very high and depended on whether patients were on
beta-blocker treatment. CONCLUSIONS: Prescribed exercise intensity should be
within VT1 and VT2, so that the efficacy and safety is guaranteed.
If determining
VT1 and VT2 is not possible, HR-based methods can be used, but with caution. In
fact, there will be always a proportion of patients training below VT1 or above
VT2. On the other hand, recommendations for patients on a beta-blocker should be
different from patients not receiving a beta-blocker. Patients not treated with a
beta-blocker should exercise at HRKarv0.7 or at HR85%. In patients on a
beta-blocker, we recommend preferentially a target HR of HRKarv0.6 or HR80%.
CI - (c) The European Society of Cardiology 2013 Reprints and permissions:
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Langue : ANGLAIS