en فيزيولوژی ورزشی و شاخه‌های وابسته بدان Sport Physiology and its related branches مقاله اصیل Original Article <div style="text-align: justify;"><strong>Background.</strong> The acute ingestion of ketone body supplements can improve exercise responses such as oxygen consumption and blood lactate. Additionally, ketone body supplements show increases in circulating &beta;hb concentration, matching those of someone in a state of nutritional ketosis. Studies testing ketone body supplements have reported different results in exercise response and varying gastrointestinal discomfort.<br> <strong>Objectives.</strong> This study aimed to compare the effects of exogenous ketone supplements on submaximal exercise response in a group of trained male cyclists.<br> <strong>Methods.</strong> A randomized, double-blind study was conducted. Forty-four males were randomly assigned to one of four supplement groups, i.e., high ketone (HKET) (10g &beta;hb); low ketone (LKET) (4g &beta;hb); carbohydrate (CHO); or placebo (PLA). Oxygen consumption and blood lactate were measured as markers of exercise response and blood &beta;hb as a marker for ketosis, during a submaximal cycle protocol (30 min at 60% VO2max).<br> <strong>Results.</strong> Two of the three supplements increased oxygen consumption (CHO: p<0.0005; and HKET: p=0.015). The HKET group experienced an increase in maximal blood lactate (P = 0.010) and a decrease in lactate threshold (d=0.93). Additionally, the HKET group showed the largest increase in circulating &beta;hb concentration (P = 0.004) 30 minutes following ingestion. The respiratory exchange ratio, heart rate, and plasma glucose were not affected.<br> <strong>Conclusion.</strong> Although the exogenous ketone supplements were able to induce a mild state of ketosis (>0.5 mmol/L),&nbsp; no positive effect on exercise response was shown.</div> Beta-Hydroxybutyrate, Ketone Bodies, Ketone Supplements, Cycling Exercise Performance 0 0 http://aassjournal.com/browse.php?a_code=A-11-1344-1&slc_lang=en&sid=1 Devon Da Costa devdacosta@hotmail.com 10031947532846008502 10031947532846008502 No College of Health Sciences, Discipline of Biokinetics, Exercise and Leisure Sciences, University of KwaZulu-Natal, South Africa Varsha Banagalee bangalee@ukzn.ac.za 10031947532846008503 10031947532846008503 No College of Health Sciences, Discipline of Pharmaceutical Sciences, University of KwaZulu-Natal, South Africa Rowena Naidoo naidoor3@ukzn.ac.za 10031947532846008504 10031947532846008504 Yes College of Health Sciences, Discipline of Biokinetics, Exercise and Leisure Sciences, University of KwaZulu-Natal, South Africa