The purpose of this study was to compare effects of different amounts of carbohydrate (CHO) in beverage on plasma glucose (GLU) concentration during exercise after feeding breakfast. Seven healthy Japanese male subjects performed 30-min cycling at an intensity on the 75% of maximal load at 3-h after feeding breakfast under 3 types of CHO (0 g, 30 g and 150 g) beverage conditions. The subjects ingested 500 mL of beverage dissolved each amount of glucose at 30-min before the exercise. The GLU concentrations were measured at 35- and 10-min before the exercise and every 5-min during the exercise. The minimum GLU concentrations under the 30 g condition for all subjects were lower than a criterion for hypoglycemic (72 mg / dL). The mean value also fell below the criterion at from 10- to 20-min during exercise. The minimum GLU concentration under the 150 g condition of only one subject was lower than the criterion, but the mean value did not fall below the criterion. Significant negative correlations were found between the subjects’ maximum oxygen uptake (VO₂max) and the decreases in GLU concentration from maximum to minimum under both the 30 g (r = -0.947, p < 0.01) and 150 g conditions (r = -0.884, p < 0.01). This study clarified that feeding breakfast at 3-h before the exercise followed by the 30 g CHO beverage ingestion at 30 min before the exercise induced exercise-induced hypoglycemia, and that the subjects with higher VO₂max had the greater decreases in GLU concentration.

The aims were to investigate the changes in physical activity of university students after the COVID-19 emergency declaration was lifted, and to determine whether there were any differences in these changes between academic years. The subjects were 81 students attending university or graduate school in Kochi Prefecture who completed a baseline survey (May 2020). Analysis 1, included 51 subjects who responded to both the baseline survey and the retrospective survey (October 2020) on physical activity at 1 year prior. In Analysis 2, 71 subjects who participated in at least one follow-up examination (August 2020, November 2020) were included. The International Physical Activity Questionnaire – Long Form was used to assess physical activity and sitting time per week. Between October 2019 and May 2020, the total (-47.7%), vigorous (-59.3%) and moderate (-42.1%) physical activity decreased, and sitting time (+36.9%) increased. The interaction between the time of the survey and year of university (first-year, ≥second-year), analyzed using a generalized linear mixed model, on total, vigorous, walking physical activity and sitting time was significant. Especially, the estimate of least squares mean after inverse square root transformation of total physical activity in first-year students was higher in November 2020 (8192.4 METs·min/week) compared to baseline (3388.5 METs·min/week). Vigorous physical activity in first-year students was also higher in November 2020 (4773.3 METs·min/week) compared to baseline (1060.3 METs·min/week). The emergency declaration in April 2020 inhibited physical activity among university students, and the impact was particularly strong among first-year students.

This study aimed to clarify the effects of carbohydrate mouth rinse on exercise performance. We examined the effect of mouth rinse on fatigability. Thirty healthy male college students completed three trials with non mouth rinse (CON), mouth rinse intervention of 6% glucose (GMR), and artificial sweetener (PLA). Handgrip exercise was performed as a fatigue task. The subjects performed a 10-seconds maximal voluntary contraction (MVC) followed by a 40% MVC rhythmic grasping movement for 14 per minutes, followed by a 4-seconds rest. This set of exercises was performed for a total of ten sets. Mouth rinse was performed from the 5th set to the 10th set. The subjects were divided into three groups: L, M, and S, according to the degree of decrease in MVC due to fatigue in CON. The effect was evaluated using the rate of change in MVC after the mouth rinse. The evaluation was performed for each trail and group. In the L group, mouth rinse significantly improved the rate of change of MVC compared with the other trials (GMR vs. CON: P = 0.002; PLA vs. CON: P = 0.042). A significant trend was observed in the M (GMR vs. CON: P = 0.062), but not in the S. In conclusion, the effects of mouth rinse differed depending on fatigability in isometric hand grip performance, with mouth rinse inhibiting the decrease of motor fatigue. In addition, it was suggested that the sweetness of carbohydrates may have an effect on mouth rinse.