Spee, Ruud F; Niemeijer, Victor M; Wijn,
Pieter F; Doevendans, Pieter A; Kemps, Hareld M.

European Journal of Preventive Cardiology, December 2016, Vol. 23 Issue: Number 18
p1943-1952, 10p

Abstract: Background
High-intensity interval training
(HIT) improves exercise capacity in patients with chronic heart failure
(CHF). Moreover, HIT was associated with improved resting cardiac
function. However, the extent to which these improvements actually
contribute to training-induced changes in exercise capacity remains to
be elucidated. Therefore, we evaluated the effects of HIT on exercising
central haemodynamics and skeletal muscle oxygenation.Methods
Twenty-six CHF patients were randomised to a 12-week 4 × 4 minute HIT
program at 85–95% of peak VO2or usual care. Patients performed maximal
and submaximal cardiopulmonary exercise testing with simultaneous
assessment of cardiac output and skeletal muscle oxygenation by near
infrared spectroscopy, using the amplitude of the tissue saturation
index (TSIamp).

Results  Peak workload increased by 11% after HIT
(pbetween group = 0.01) with a non-significant increase in peak
VO2(+7%, pbetween group = 0.19). Cardiac reserve increased by 37% after
HIT (p within group = 0.03, pbetween group = 0.08); this increase was
not related to improvements in peak workload. Oxygen uptake recovery
kinetics after submaximal exercise were accelerated by 20% (pbetween
group = 0.02); this improvement was related to a decrease in TSIamp
(r= 0.71, p= 0.03), but not to changes in cardiac output
kinetics.

Conclusion  HIT induced improvements in maximal exercise
capacity and exercising haemodynamics at peak exercise. Improvements in
recovery after submaximal exercise were associated with attenuated
skeletal muscle deoxygenation during submaximal exercise, but not with
changes in cardiac output kinetics, suggesting that the effect of HIT
on submaximal exercise capacity is mediated by improved microvascular
oxygen delivery-to-utilisation matching.; (AN 40419387)