High-intensity intermittent cycling increases purine loss compared with workload-matched continuous moderate intensity cycling

Abstract

PurposeExercise at 50–60 % of peak oxygen consumption (VO2 peak) stimulates maximal fat oxidation rates. Despite a lower estimated work performed; high-intensity intermittent exercise (HIIE) training produces greater fat mass reductions when compared with workload-matched continuous (CON) steady state exercise. No metabolic basis has been documented nor mechanisms offered to explain this anomaly. This study investigated the physiological and metabolic responses of two different workload-matched exercise protocols.MethodsOn separate occasions and at least 1 week apart, eight apparently healthy males cycled for 30 min at either 50 % VO2 peak (CON) or performed repeated 20 s bouts of supramaximal exercise at 150 %VO2 peak separated by 40 s rest (HIIE).ResultsThe average heart rate, oxygen consumption, plasma glycerol and free fatty acid concentrations were not different during exercise and recovery between the trials. Plasma lactate and hypoxanthine (Hx) concentrations were elevated and urinary excretion rates of Hx and uric acid were greater following HIIE as compared to CON (P < 0.05).ConclusionExercise-induced plasma Hx accumulation and urinary purine excretion are greater following HIIE and indirectly represents a net loss of adenosine triphosphate (ATP) from the muscle. The subsequent restorative processes required for intramuscular de novo replacement of ATP may contribute to a negative energy balance and in part, account for the potential accelerated fat loss observed with HIIE when compared with CON training programs.

The Effects of a Short-Term High-Intensity Interval Training (HIIT) on the Levels of Serum Hypoxanthine-Guanine Phosphoribosyltransferase (HGPRT) Enzyme and Some Variables of Purine Nucleotide Cycle

“…On the other hand, since hypoxanthine indicates ATP energy discharge, it can be considered as an indicator for energy discharge and cellular metabolic stress (18). In this study that showed the significant increase of xanthine and hypoxanthine concentrations, this increase represents the high decomposition of ATP in high-intensity interval activities, and this study is thus consistent with Gerber et al (19,20). Similarly, Zielinski et al in their research studies reported an increase in xanthine and hypoxanthine levels after the activity of these variables.…”

Anaerobic exercise affects the saliva antioxidant/oxidant balance in high-performance pentathlon athletes

“…This chemical feature may mean that uric acid helps to control oxidative stress generated by exercise, at the same time reflecting greater ATP flux associated with elevated energy requirements. Purine catabolism increases and the higher concentrations of sub-products of this metabolism are formed [32]. Xanthine oxidoreductase is a key intracellular enzyme of purine metabolism.…”

Comparison between continuous and intermittent submaximal exercise at the intensity of maximal fat oxidation

“…In addition to this, when changes in substrate oxidation rates in bicycle ergometer at the level of 50% of 90 minute maxVO 2 during continuous and intermittent exercises, it was figured out that there was no significant difference on total energy expenditure; however, in intermittent exercises the fat oxidation rate was lower than continuous exercises (Warren et al, 2009). On the other hand, Gerber et al (2014) stated that more fat loss observed with the high intensity intermittent exercise when compared with continuous steady state exercise.…”