title: Moderate and heavy metabolic stress interval training improve arterial stiffness and heart rate dynamics in humans.
abstract: Traditional continuous aerobic exercise training attenuates age-related increases of arterial stiffness, however, training studies have not determined whether metabolic stress impacts these favourable effects. Twenty untrained healthy participants (n = 11 heavy metabolic stress interval training, n = 9 moderate metabolic stress interval training) completed 6 weeks of moderate or heavy intensity interval training matched for total work and exercise duration. Carotid artery stiffness, blood pressure contour analysis, and linear and non-linear heart rate variability were assessed before and following training. Overall, carotid arterial stiffness was reduced (p < 0.01), but metabolic stress-specific alterations were not apparent. There was a trend for increased absolute high-frequency (HF) power (p = 0.10) whereas both absolute low-frequency (LF) power (p = 0.05) and overall power (p = 0.02) were increased to a similar degree following both training programmes. Non-linear heart rate dynamics such as detrended fluctuation analysis [Formula: see text] also improved (p > 0.05). This study demonstrates the effectiveness of interval training at improving arterial stiffness and autonomic function, however, the metabolic stress was not a mediator of this effect. In addition, these changes were also independent of improvements in aerobic capacity, which were only induced by training that involved a high metabolic stress.
authors.affiliation: Health, Exercise and Active Life Research Unit, Sport and Exercise Sciences, Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK. merako@essex.ac.uk
authors.forename: Mark
authors.initials: M
authors.lastname: Rakobowchuk
authors.forename: Emma
authors.initials: E
authors.lastname: Harris
authors.forename: Annabelle
authors.initials: A
authors.lastname: Taylor
authors.forename: Richard M
authors.initials: RM
authors.lastname: Cubbon
authors.forename: Karen M
authors.initials: KM
authors.lastname: Birch
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000503:physiopathology; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D059168:Carotid Intima-Media Thickness; D004562:Electrocardiography; D004739:England; D015444:Exercise; D005260:Female; D006339:Heart Rate; D006801:Humans; D016014:Linear Models; D008297:Male; D017711:Nonlinear Dynamics; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D063177:Pulse Wave Analysis; D013312:Stress, Physiological; D013997:Time Factors; D016896:Treatment Outcome; D059289:Vascular Stiffness; D055815:Young Adult