Long-term high-intensity interval training associated with lifestyle modifications improves QT dispersion parameters in metabolic syndrome patients

• Published in: Annals of physical and rehabilitation medicine Vol. 56; no. 5; pp. 356 - 370
• Main Authors: Drigny, J, Gremeaux, V, Guiraud, T, Gayda, M, Juneau, M, Nigam, A
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Masson SAS 01-07-2013
• Subjects: Adult; Body Mass Index; Cardiometabolic risk; Cholesterol, HDL - blood; Cholesterol, LDL - blood; Electrocardiography; Entraînement par intervalles; Exercice; Exercise; Heart - physiopathology; Heart Rate; Humans; Internal Medicine; Interval exercise training; Life Style; Metabolic syndrome; Metabolic Syndrome - blood; Metabolic Syndrome - physiopathology; Metabolic Syndrome - rehabilitation; Middle Aged; Physical Conditioning, Human - methods; Physical Conditioning, Human - physiology; Physical Medicine and Rehabilitation; Repolarisation ventriculaire; Retrospective Studies; Risque cardiométabolique; Syndrome métabolique; Time Factors; Triglycerides - blood; Ventricular repolarization; Waist Circumference; Weight Loss; Exercise; Exercice; Interval exercise training; Risque cardiométabolique; Ventricular repolarization; Cardiometabolic risk; Entraînement par intervalles; Metabolic syndrome; Syndrome métabolique; Repolarisation ventriculaire
• ISSN: 1877-0657; 1877-0665
• DOI: 10.1016/j.rehab.2013.03.005

Abstract Background 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 ± 9 years) were assigned to either a MICE (60% of peak power output [PPO]), or a HIIT program (alternating phases of 15–30 s at 80% of PPO interspersed by passive recovery phases of equal duration), twice weekly during 9 months. 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 56 ms in MICE, P < 0.05; 34 vs 38 ms 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.