Acute effects of exercise intensity on subsequent substrate utilisation, appetite and energy balance in men and women.

Exercise is capable of influencing the regulation of energy balance by acutely modulating appetite and energy intake coupled to effects on substrate utilization. Yet, few studies have examined acute effects of exercise intensity on aspects of both energy intake and energy metabolism, independently of energy cost of exercise. Furthermore, little is known as to the gender differences of these effect. One hour after a standardised breakfast, 40 (19 female), healthy participants (BMI 23.6Âą3.6 kg.m-2, VO2peak 34.4Âą6.8 ml.min-1.min-1) undertook either High intensity intermittent cycling consisting of 8 repeated 60s bouts of cycling at 95% VO2peak (HIIC) or low intensity continuous cycling, equivalent to 50% VO2peak (LICC), matched for energy cost (~950kJ) followed by 90mins of rest, in a randomised crossover design. Throughout each study visit satiety was assessed subjectively using visual analogue scales alongside blood metabolites and GLP-1. Energy expenditure and substrate utilization were measured over 75 minutes post-exercise via indirect calorimetry. Energy intake was assessed for 48hours post-intervention. No differences in appetite, GLP-1 or energy intakes were observed between HIIC and LICC, with or without stratifying for gender. Significant differences in post exercise non-esterified fatty acid (NEFA) concentrations were observed between intensities in both genders, coupled to a significantly lower respiratory exchange ratio (RER) following HIIC (P=0.0028), with a trend towards greater reductions in RER in men(P=0.079). In conclusion, high intensity exercise, if energy matched, does not lead to greater appetite or energy intake but may exert additional beneficial metabolic effects that may be more pronounced in males.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author