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

Ann Phys Rehabil Med. 2013 Jul;56(5):356-70. doi: 10.1016/j.rehab.2013.03.005. Epub 2013 Apr 17.


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.

Keywords: Cardiometabolic risk; Entraînement par intervalles; Exercice; Exercise; Interval exercise training; Metabolic syndrome; Repolarisation ventriculaire; Risque cardiométabolique; Syndrome métabolique; Ventricular repolarization.

MeSH terms

  • Adult
  • Body Mass Index
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Electrocardiography
  • Heart / physiopathology*
  • Heart Rate
  • Humans
  • Life Style*
  • Metabolic Syndrome / blood
  • Metabolic Syndrome / physiopathology*
  • Metabolic Syndrome / rehabilitation*
  • Middle Aged
  • Physical Conditioning, Human / methods
  • Physical Conditioning, Human / physiology*
  • Retrospective Studies
  • Time Factors
  • Triglycerides / blood
  • Waist Circumference
  • Weight Loss


  • Cholesterol, HDL
  • Cholesterol, LDL
  • Triglycerides