Article

QT dispersion (QTd) is a marker of myocardial electrical instability,
and is increased in metabolic syndrome (MetS). Moderate intensity continuous
exercise (MICE) training was shown to improve QTd in MetS patients. OBJECTIVES:
To describe long-term effects of MICE and high-intensity interval exercise
training (HIIT) on QTd parameters in MetS. METHODS: Sixty-five MetS patients
(53+/-9years) were assigned to either a MICE (60% of peak power output [PPO]), or
a HIIT program (alternating phases of 15-30s at 80% of PPO interspersed by
passive recovery phases of equal duration), twice weekly during 9months.
Ventricular repolarization indices (QT dispersion=QTd, standard deviation of
QT=sdQT, relative dispersion of QT=rdQT, QT corrected dispersion=QTcd),
metabolic, anthropometric and exercise parameters were measured before and after
the intervention. RESULTS: No adverse events were noted during exercise. QTd
decreased significantly in both groups (51 vs 56ms in MICE,
P<0.05; 34 vs 38ms in
HIIT, P<0.05). Changes in QTd were correlated with changes in maximal heart rate
(r=-0.69, P<0.0001) and in heart rate recovery (r=-0.49, P<0.01) in the HIIT
group only. When compared to MICE, HIIT training induced a greater decrease in
weight, BMI and waist circumference. Exercise capacity significantly improved by
0.82 and 1.25 METs in MICE and HIIT groups respectively (P<0.0001). Lipid
parameters also improved to the same degree in both groups. CONCLUSION: In MetS,
long-term HIIT and MICE training led to comparable effects on ventricular
repolarization indices, and HIIT might be associated with greater improvements in
certain cardiometabolic risk factors.
CI - Copyright (c) 2013 Elsevier Masson SAS. All rights reserved.

Langue : ANGLAIS ; FRANCAIS