The purpose of this case study was to longitudinally elucidate energy availability from the dietary and training records of a Japanese female athlete (adult competitive swimmer) with disordered eating and amenorrhea during the competitive season. As a result, the subject’s energy availability was below 30 kcal/kg FFM/day throughout approximately three months of the study period. This indicates a continuous mismatch between the subject’s total energy intake (diet) and energy expended in exercise (i.e., low energy availability: leaving inadequate energy to support the functions required by the body to maintain optimal health and performance), which is clearly linked to amenorrhea. In order to return physiological function to normal while continuing athletic activities (i.e., ensuring sufficient energy availability), the subject needs to increase total energy intake through appropriate intake of each energy-providing nutrient (especially carbohydrates).

The purpose of this study was to investigate the relationship between blood glucose (Glu) response and respiratory exchange ratio (RER) during an intermittent incremental swimming test in well-trained swimmers. Seven male swimmers participated in this study. The participants conducted an intermittent incremental swimming test consisting of 3-min periods of swimming with 2-min intervals in a swimming flume. Blood lactate (Bla) and Glu were measured after each incremental swimming step. Metabolic response was measured continuously to investigate RER. As results, Glu remained at a similar level throughout the test, whereas Bla and RER abruptly increased at high-intensity swimming stage. Rise in RER reflects the increase in carbohydrate oxidation, it was clarified that Glu did not increase while carbohydrate metabolism enhanced. It was speculated that Glu clearance from the blood was higher during high-intensity swimming, which result in different Glu response compared to exercise on land.