Left ventricular vascular and metabolic adaptations to high‐intensity interval and moderate intensity continuous training: a randomized trial in healthy middle‐aged men

Abstract

High-intensity interval training (HIIT) is a time-efficient way of obtaining the health benefits of exercise, although the cardiac effects of this training mode are incompletely known. We compared the effects of short-term HIIT and moderate intensity continuous training (MICT) interventions on myocardial perfusion and metabolism and cardiac function in healthy, sedentary, middle-aged men. Twenty-eight healthy, middle-aged men were randomized to either HIIT or MICT groups (n = 14 in both) and underwent six cycle ergometer training sessions within 2 weeks (HIIT session: 4-6 × 30 s all-out cycling/4 min recovery, MICT session 40-60 min at 60% V̇O2 peak ). Cardiac magnetic resonance imaging (CMRI) was performed to measure cardiac structure and function and positron emission tomography was used to measure myocardial perfusion at baseline and during adenosine stimulation, insulin-stimulated glucose uptake (MGU) and fasting free fatty acid uptake (MFFAU). End-diastolic and end-systolic volumes increased and ejection fraction slightly decreased with both training modes, although no other changes in CMRI were observed. MFFAU and basal myocardial perfusion remained unchanged. MGU was decreased by training (HIIT from 46.5 to 35.9; MICT from 47.4 to 44.4 mmol 100 g min , P = 0.007 for time, P = 0.11 for group × time). Adenosine-stimulated myocardial perfusion responded differently to the training modes (change in mean HIIT: -19%; MICT: +9%; P = 0.03 for group × time interaction). HIIT and MICT induce similar metabolic and functional changes in the heart, although myocardial vascular hyperaemic reactivity is impaired after HIIT. This should be taken into account when prescribing very intense HIIT for previously untrained subjects.

Automated production of [18F]FTHA according to GMP

“…Regardless of the development of new tracers, [ 18 F]FTHA is still widely used. At Turku PET Centre, we have used [ 18 F]FTHA in numerous studies of fatty acid metabolism in, for example, the myocardium, adipose tissue function, and obesity …”

Extremely short duration sprint interval training improves vascular health in older adults

“…Given our findings are of a similar magnitude, even though total weekly duration is much lower, then this suggests that the duration of the sprint is not a driving factor in blood pressure adaptation to SIT. Ejection fraction does not appear to change with either endurance training [4] or with 30-s repeated high intensity bursts [29] and resting heart rate was unchanged in this study (data not reported). It could be speculated that improvements in pulse pressure at rest, reported in this study, reflect changes in arterial stiffness or wave reflection.…”

Exercise Training Reduces Intrathoracic Fat Regardless of Defective Glucose Tolerance

“…We have previously published several reports from this study (9,10,16,17,24,25,37). The main parameters of the present study, epi- and pericardial fat masses and MTC, have not been published before neither in healthy nor in DGT subjects.…”