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

Gerber T, Borg ML, Hayes A, Stathis CG - Eur. J. Appl. Physiol. (2014)

Bottom Line: 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.Exercise-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.

View Article: PubMed Central - PubMed

Affiliation: College of Health and Biomedicine, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.

ABSTRACT

Purpose: Exercise 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.

Methods: On 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).

Results: The 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).

Conclusion: Exercise-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.

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Plasma glucose and lactate during CON and HIIE exercise. Plasma glucose (a) and plasma lactate (b) measured during exercise and recovery from CON and HIIE. Data are mean ± SEM. *P < 0.05 CON vs. HIIE at a given time point, n = 8 per group. CON white circles, HIIE black circles. Grey box represents the recovery period
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Fig1: Plasma glucose and lactate during CON and HIIE exercise. Plasma glucose (a) and plasma lactate (b) measured during exercise and recovery from CON and HIIE. Data are mean ± SEM. *P < 0.05 CON vs. HIIE at a given time point, n = 8 per group. CON white circles, HIIE black circles. Grey box represents the recovery period

Mentions: Plasma glucose concentrations were not different between trials and were maintained within a range between 4.95 and 5.26 mM for the duration of the two trials (Fig. 1a). Plasma lactate increased significantly from rest with exercise during the HIIE trial (P < 0.05) and was threefold higher in HIIE when compared with CON at the end of exercise (P = 0.0028) (Fig. 1b). Lactate in HIIE remained elevated above CON early in the recovery period (P = 0.039). Plasma glycerol was elevated during the exercise and recovery periods (P < 0.05 main effect), but was not different between trials. During the exercise, plasma FFA tended to be elevated in the HIIE trial (P = 0.06 main effect) and did not differ during the recovery period.Fig. 1


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

Gerber T, Borg ML, Hayes A, Stathis CG - Eur. J. Appl. Physiol. (2014)

Plasma glucose and lactate during CON and HIIE exercise. Plasma glucose (a) and plasma lactate (b) measured during exercise and recovery from CON and HIIE. Data are mean ± SEM. *P < 0.05 CON vs. HIIE at a given time point, n = 8 per group. CON white circles, HIIE black circles. Grey box represents the recovery period
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Related In: Results  -  Collection

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Fig1: Plasma glucose and lactate during CON and HIIE exercise. Plasma glucose (a) and plasma lactate (b) measured during exercise and recovery from CON and HIIE. Data are mean ± SEM. *P < 0.05 CON vs. HIIE at a given time point, n = 8 per group. CON white circles, HIIE black circles. Grey box represents the recovery period
Mentions: Plasma glucose concentrations were not different between trials and were maintained within a range between 4.95 and 5.26 mM for the duration of the two trials (Fig. 1a). Plasma lactate increased significantly from rest with exercise during the HIIE trial (P < 0.05) and was threefold higher in HIIE when compared with CON at the end of exercise (P = 0.0028) (Fig. 1b). Lactate in HIIE remained elevated above CON early in the recovery period (P = 0.039). Plasma glycerol was elevated during the exercise and recovery periods (P < 0.05 main effect), but was not different between trials. During the exercise, plasma FFA tended to be elevated in the HIIE trial (P = 0.06 main effect) and did not differ during the recovery period.Fig. 1

Bottom Line: 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.Exercise-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.

View Article: PubMed Central - PubMed

Affiliation: College of Health and Biomedicine, Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.

ABSTRACT

Purpose: Exercise 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.

Methods: On 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).

Results: The 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).

Conclusion: Exercise-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.

Show MeSH
Related in: MedlinePlus