Metabolic and hormonal responses to isoenergetic high-intensity interval exercise and continuous moderate-intensity exercise

Abstract

This study investigated the effects of high-intensity interval training (HIIT) vs. work-matched moderate-intensity continuous exercise (MOD) on metabolism and counterregulatory stress hormones. In a randomized and counterbalanced order, 10 well-trained male cyclists and triathletes completed a HIIT session [81.6 Ϯ 3.7% maximum oxygen consumption (V O2 max); 72.0 Ϯ 3.2% peak power output; 792 Ϯ 95 kJ] and a MOD session (66.7 Ϯ 3.5% V O2 max; 48.5 Ϯ 3.1% peak power output; 797 Ϯ 95 kJ). Blood samples were collected before, immediately after, and 1 and 2 h postexercise. Carbohydrate oxidation was higher (P ϭ 0.037; 20%), whereas fat oxidation was lower (P ϭ 0.037; Ϫ47%) during HIIT vs. MOD. Immediately after exercise, plasma glucose (P ϭ 0.024; 20%) and lactate (P Ͻ 0.01; 5.4ϫ) were higher in HIIT vs. MOD, whereas total serum free fatty acid concentration was not significantly different (P ϭ 0.33). Targeted gas chromatography-mass spectromtery metabolomics analysis identified and quantified 49 metabolites in plasma, among which 11 changed after both HIIT and MOD, 13 changed only after HIIT, and 5 changed only after MOD. Notable changes included substantial increases in tricarboxylic acid intermediates and monounsaturated fatty acids after HIIT and marked decreases in amino acids during recovery from both trials. Plasma adrenocorticotrophic hormone (P ϭ 0.019), cortisol (P Ͻ 0.01), and growth hormone (P Ͻ 0.01) were all higher immediately after HIIT. Plasma norepinephrine (P ϭ 0.11) and interleukin-6 (P ϭ 0.20) immediately after exercise were not significantly different between trials. Plasma insulin decreased during recovery from both HIIT and MOD (P Ͻ 0.01). These data indicate distinct differences in specific metabolites and counterregulatory hormones following HIIT vs. MOD and highlight the value of targeted metabolomic analysis to provide more detailed insights into the metabolic demands of exercise. exercise intensity; metabolites; stress hormones; amino acids; free fatty acids; tricarboxylic acid intermediates INTEREST IN HIGH-INTENSITY exercise as an effective mode of exercise training has intensified over the past decade in recognition of three main factors that are commonly cited as limitations to regular physical activity: lack of time, lack of motivation, and chronic diseases that restrict work capacity during exercise (64). This type of training generally consists of relatively brief, intermittent exercise performed either at "allout" effort or at intensities close to maximum oxygen consumption (V O 2 max ) (16). The body of literature supporting the health and fitness benefits of high-intensity interval training (HIIT) is expanding. So too is our knowledge of the molecular mechanisms that accompany adaptations to this form of training (19).Improved metabolism is integral to the benefits of HIIT. Carbohydrate (CHO) oxidation increases with exercise intensity, whereas fat oxidation increases during exercise up to 65-75% V O 2 max and decreases at higher workloads (52, 60). Exercise also stimulates amino ...

Global Metabolic Stress of Isoeffort Continuous and High Intensity Interval Aerobic Exercise: A Comparative 1H NMR Metabonomic Study

“…In general, we did not observe substantial changes in plasma amino acids immediately after the three exercise protocols. Alanine increased in all three types of exercise which is in accordance with most previous studies that used either short or prolonged endurance exercise protocols 12,[51][52][53] . Based on previous studies, the increase in plasma alanine seems likely the result of an excessive pyruvate accumulation in the muscle as part of the TCAi pool anaplerotic reactions and the activation of alanine-glucose cycle to replenish the carbohydrate/glycogen supplies 48,53 .…”

“…Therefore, metabonomics is being increasingly used to examine the metabolic stress to a single exercise bout [7][8][9][10][11][12][13][14] .…”

Modified sprint interval training protocols. Part I. Physiological responses

“…Additionally, catecholamine-induced increases in lipolysis and metabolism (Zouhal et al 2008) may have been more pronounced with longer compared with shorter sprint bouts (Trapp et al 2007). Although this lipolytic effect has not always been reported (Williams et al 2013), several studies have shown increases in catecholamines (Trapp et al 2007;Williams et al 2013), free fatty acids (Peake et al 2014), and glycerol (McCartney et al 1986;Trapp et al 2007) after intense intermittent exercise, all of which are indicative of increased fat oxidation (Whyte et al 2010;Chan and Burns 2013;Beaulieu et al 2015). These observations are further supported by the improvements in muscle fat oxidative capacity achieved after training (Burgomaster et al 2008;Perry et al 2008;Gillen et al 2013Gillen et al , 2014.…”

Metabolic and endocrine response to exercise: sympathoadrenal integration with skeletal muscle

“…A wide range of metabolites present in plasma and serum has been determined using liquid chromatography mass spectrometry and/or gas-chromatography mass spectrometry collected pre-and post-exercise. In most cases, a wide range of metabolites have been reported (Pohjanen et al 2007, Lewis et al 2010, Peake et al 2014 to exist and that with exercise changes in metabolites related to carbohydrate, triglyceride and markers of the tricarboxylic acid have been reported. Peake et al (2014), these studies were not hypothesis driven and are more observational in nature.…”

“…In most cases, a wide range of metabolites have been reported (Pohjanen et al 2007, Lewis et al 2010, Peake et al 2014 to exist and that with exercise changes in metabolites related to carbohydrate, triglyceride and markers of the tricarboxylic acid have been reported. Peake et al (2014), these studies were not hypothesis driven and are more observational in nature. However, the use of metabolomics could provide a unique insight into the co-ordinated metabolic response to exercise in terms of substrate mobilisation, utilisation and the production of metabolic by-products.…”