Results from the Japan 2022 report card on physical activity for children and youth

Background/Objective: The 2020 Tokyo Olympics and Paralympic was held in 2021, although postponed due to the spread of COVID-19. This event might have an impact on physical activity (PA) of children and adolescents, but the national data on PA during the pandemic were not available. Therefore, the goal of the 2022 Japan Report Card on Physical Activity for Children and Youth (The 2022 Japan Report Card) is to assess and track levels of health behaviors related to PA, and health outcomes in Japanese children and adolescents, and environments and government strategy for PA just before the pandemic. Methods: The 2022 Japan Report Card consists of health behaviors and outcomes (8 indicators), and influences on health behaviors (4 indicators). Nationally representative data were used to score the indicators. Results: The key five health behaviors and outcomes (Overall PA: B −; Organized Sport: B −; Active Transportation: A −; Physical fitness: B, Weight status: A) were favorable. Sedentary Behavior and Sleep received C − and D − grades, respectively. Active Play could not be graded (INC). In the influences domain, Family and Peers was graded as C −, while School (B +), Community and Environment (B), and Government (B) were favorable. Conclusions: The 2022 Japan Report Card shows that Japanese children and adolescents had favorable levels of overall PA, active transportation to and from school, and weight status, and there was a generally favorable environment for PA and health, though sedentary behavior and sleep were unfavorable. Future nationally representative surveys on active play are needed

Changes in Season Affect Body Weight, Physical Activity, Food Intake, and Sleep in Female College Students: A Preliminary Study

The current study examined how body weight and lifestyle fluctuate between spring, autumn, and winter in Japanese female college students and whether weight gain is associated with changes in physical activity, food intake, and sleep. We measured body weight and lifestyle factors in 31 participants from May 2017 to January 2018. Weight was measured daily in participants’ homes. Physical activity and sleep were measured for three weeks in three seasons using two accelerometers. Food intake was assessed using a validated food frequency questionnaire. Body weight significantly decreased in autumn compared with spring (p < 0.001). Body weight in winter tended to increase compared with autumn (p = 0.052). Step counts and energy intake were significantly different between seasons (p < 0.05). Total time in bed was not significantly different between seasons. In comparisons of changes in lifestyle patterns from autumn to winter between the weight gain (≥0.5 kg) and weight maintenance groups, seasonal changes in lifestyle factors were not significantly different between groups (p > 0.05). The results indicated that body weight and lifestyle were affected by seasonal variability in female college students, but no significant relationships existed between seasonal weight gain and changes in lifestyle patterns

Energy Expenditure of a Single Sit-to-Stand Movement with Slow Versus Normal Speed Using the Different Frequency Accumulation Method

Background and objectives: The purpose of this study was to compare the energy expenditures (EE) of a single sit-to-stand (STS) movements with slow and normal speeds using a multi-stage exercise test. Materials and Methods: Twelve young males, aged 21–27 years (age, 23.0 ± 1.7 years; height, 171.2 ± 6.1 cm; weight, 64.3 ± 5.6 kg), performed repeated 3-s stand-up and 3-s sit-down (slow) or 1-s stand-up and 1-s sit-down (normal) movement on two different days with random order. All the participants completed multi-stage tests at different STS frequencies per minute. The slope and intercept of the linear regression relationship between the EE (kcal/min) and the STS frequency were obtained, and the slope of the regression was quantified as the EE of an STS. Results: The metabolic equivalents (METs) of the STS-slow was 4.5 METs for the frequency of 10 times/min (in total 1 min), and the net EE was 5.00 ± 1.2 kcal/min. The net EE of the STS-slow was 0.37 ± 0.12 kcal, which was significantly greater than that during the STS-normal (0.26 ± 0.06 kcal). The difference between the EEs of the STS-slow and STS-normal was significantly greater in taller and heavier subjects. Conclusions: We concluded that the intensity of STS-slow movement is moderate, and the EE during an STS-slow (0.37 ± 0.12 kcal) is higher than that during an STS-normal (0.26 ± 0.06 kcal). Our study results will help exercise and/or health professionals prescribe physical activity programs using STS movement for healthy young population groups

Mothers’ Nutrition Knowledge Is Unlikely to Be Related to Adolescents’ Habitual Nutrient Intake Inadequacy in Japan: A Cross-Sectional Study of Japanese Junior High School Students

Dietary habits in adolescence persist into adulthood; thus, it is important to identify the factors that influence adolescent diet and establish a healthy diet. This study aimed to examine the association between mothers’ nutrition knowledge and their children’s nutrient intake inadequacy among Japanese junior high school student–mother dyads. The participants were 288 students and their mothers. Data regarding mothers’ nutrition knowledge were obtained using a validated, self-administered general nutrition knowledge questionnaire for Japanese adults (JGNKQ). Participants were categorised into two groups according to the mothers’ total JGNKQ scores. Adolescents’ dietary habits during the preceding month were assessed using a brief self-administered diet history questionnaire. Inadequacy of each nutrient intake was assessed using the cut-point method, which showed that 14 nutrients were below “estimated average requirement (EAR)” and five nutrients were outside the range of “tentative dietary goal to prevent lifestyle-related diseases (DG)”. In the habitual daily nutrient intakes and the proportion of nutrient intake inadequacy of the students, no differences were observed according to mother’s nutritional knowledge level. Our findings suggest that mothers’ nutrition knowledge may not be directly associated with adolescents’ nutrient intake among Japanese junior high school student–mother dyads

Long-term Effects of the Use of a Step Count–Specific Smartphone App on Physical Activity and Weight Loss: Randomized Controlled Clinical Trial

BackgroundSome studies on weight loss promotion using smartphone apps have shown a weight loss effect but not an increase in physical activity. However, the long-term effects of smartphone apps on weight loss and increasing physical activity have not been rigorously examined to date. ObjectiveThe aim of this study was to assess whether the use of a smartphone app will increase physical activity and reduce body weight. MethodsIn this parallel randomized clinical trial, participants recruited between April 2018 and June 2019 were randomized in equal proportions to a smartphone app group (n=55) or a control group (n=54). The intention-to-treat approach was used to analyze the data from December 2019 through November 2021. Before the intervention, an hour-long lecture on weight loss instruction and increasing physical activity was conducted once for both groups. Participants in both groups were instructed to weigh themselves immediately after waking up at least once daily from the start of the intervention. Monthly emails were sent advising the participants in both groups on how to lose weight and increase physical activity in order to maintain or increase motivation. Participants in the smartphone app group were instructed to open the app at least once a day to check their step count and rank. The primary outcome was daily accelerometer-measured physical activity (step count) and the secondary outcome was body weight. Since there was a significant difference in the wear time of the accelerometer depending on the intervention period (P<.001), the number of steps and moderate-to-vigorous physical activity were also evaluated per wear time. ResultsThe mean age of the 109 participants in this study was 47 (SD 8) years. At baseline, the mean daily total steps were 7259 (SD 3256) steps per day for the smartphone app group and 8243 (SD 2815) steps per day for the control group. The difference in the step count per wear time between preintervention and postintervention was significantly different between the app group and the control group (average difference [95% CI], 65 [30 to 101] steps per hour vs –9 [–56 to 39] steps per hour; P=.042). The weight loss was –2.2 kg (SD –3.1%) in the smartphone app group and –2.2 kg (SD –3.1%) in the control group, with no significant difference between the groups. In addition, when divided into weekdays (Monday through Friday) and weekends (Saturday and Sunday), there was a significant interaction between step counts (P=.004) and MVPA (P=.003) during the intervention, with the app group showing higher interaction on weekends than the control group. ConclusionsIn this trial, the group with the smartphone app intervention showed increased physical activity, especially on weekends. However, this increased physical activity did not lead to increased weight loss. Trial RegistrationUniversity Hospital Medical Information Network UMIN000033397; https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R00003795

Effects of Different Physical Activity Levels during a Single Day on Energy Intake, Appetite, and Energy Balance: A Preliminary Study

We aimed to investigate the effects of a wide range of daily physical activity (PA) levels on energy balance (EB), energy intake (EI), and appetite. Nine young men completed three different PA levels in a metabolic chamber in a random order: (1) no exercise (Low-PA); (2) 25 min walking seven times (Mid-PA); and (3) 25 min running seven times (High-PA) within a 24 h period. Interval exercise (25 min exercise and 35 min rest) was performed three times in the morning and four times in the afternoon. The exercise intensities were 21.6% and 53.7% V ˙ O2 peak for the Mid-PA and High-PA days, respectively. Participants were served three standardized meals and a buffet for dinner. The 24 h EB was calculated as 24 h energy expenditure (EE) minus 24 h EI. The 24 h EEs for the Low-PA, Mid-PA, and High-PA days were 1907 &#177; 200, 2232 &#177; 240, and 3224 &#177; 426 kcal, respectively, with significant differences observed among the three conditions (p &lt; 0.01 for Low-PA vs. Mid-PA, Low-PA vs. High-PA, and Mid-PA vs. High-PA, respectively). The 24 h EIs for the Low-PA, Mid-PA, and High-PA days were 3232 &#177; 528, 2991 &#177; 617, and 3337 &#177; 684 kcal, and were unaffected by PA levels (p = 0.115). The 24 h EBs were 1324 &#177; 441 kcal (Low-PA), 759 &#177; 543 kcal (Mid-PA), and 113 &#177; 430 kcal (High-PA), with significant differences observed between Low-PA vs. Mid-PA (p = 0.0496), Low-PA vs. High-PA (p &#8804; 0.01), and Mid-PA vs. High-PA (p = 0.017) conditions. The EB in the Low-PA group was the highest of the three conditions. Appetite perception did not differ among the study days, however there was an interaction trend (p = 0.078, time &#215; condition). Thus, significantly different daily PA did not affect 24 h EI, however markedly affected 24 h EB, implying that EB is not automatically matched during a single day

The Association between Milk Intake and Nutrient Intake Adequacy among Japanese Female Junior High School Students: A Cross-Sectional Study

The consumption of dairy products, including milk, may be important for improving the overall quality of a diet. The aim of this study was to examine the relationship between milk intake and nutritional adequacy among Japanese female junior high school students. The participants of this study were Japanese female junior high school students aged between 12 and 15 years. Dietary habits over the past month were assessed by a brief self-administered diet history questionnaire. The adequacy of each nutrient intake was determined based on the Dietary Reference Intakes for Japanese 2020, with two goals: the estimated average requirement for fourteen nutrients and tentative dietary goals for preventing lifestyle-related diseases for six nutrients. The participants were classified into five groups according to milk intake (Q1 (lowest) to Q5 (highest)) by quintile. The adequacy of vitamin B2, calcium, magnesium, and potassium were higher among students with a higher milk consumption than among those with a lower milk consumption. However, the intake of saturated fatty acids was in excess among higher milk consumers. The present study suggests that milk intake was related to an adequate intake of some vitamins and minerals and an inadequate intake of saturated fatty acids among Japanese female junior high school students

The effects of exercise under hypoxia on cognitive function.

Increasing evidence suggests that cognitive function improves during a single bout of moderate exercise. In contrast, exercise under hypoxia may compromise the availability of oxygen. Given that brain function and tissue integrity are dependent on a continuous and sufficient oxygen supply, exercise under hypoxia may impair cognitive function. However, it remains unclear how exercise under hypoxia affects cognitive function. The purpose of this study was to examine the effects of exercise under different levels of hypoxia on cognitive function. Twelve participants performed a cognitive task at rest and during exercise at various fractions of inspired oxygen (FIO2: 0.209, 0.18, and 0.15). Exercise intensity corresponded to 60% of peak oxygen uptake under normoxia. The participants performed a Go/No-Go task requiring executive control. Cognitive function was evaluated using the speed of response (reaction time) and response accuracy. We monitored pulse oximetric saturation (SpO2) and cerebral oxygenation to assess oxygen availability. SpO2 and cerebral oxygenation progressively decreased during exercise as the FIO2 level decreased. Nevertheless, the reaction time in the Go-trial significantly decreased during moderate exercise. Hypoxia did not affect reaction time. Neither exercise nor difference in FIO2 level affected response accuracy. An additional experiment indicated that cognitive function was not altered without exercise. These results suggest that the improvement in cognitive function is attributable to exercise, and that hypoxia has no effects on cognitive function at least under the present experimental condition. Exercise-cognition interaction should be further investigated under various environmental and exercise conditions

The Relationship between Running Velocity and the Energy Cost of Turning during Running

<div><p>Ball game players frequently perform changes of direction (CODs) while running; however, there has been little research on the physiological impact of CODs. In particular, the effect of running velocity on the physiological and energy demands of CODs while running has not been clearly determined. The purpose of this study was to examine the relationship between running velocity and the energy cost of a 180°COD and to quantify the energy cost of a 180°COD. Nine male university students (aged 18–22 years) participated in the study. Five shuttle trials were performed in which the subjects were required to run at different velocities (3, 4, 5, 6, 7, and 8 km/h). Each trial consisted of four stages with different turn frequencies (13, 18, 24 and 30 per minute), and each stage lasted 3 minutes. Oxygen consumption was measured during the trial. The energy cost of a COD significantly increased with running velocity (except between 7 and 8 km/h, p = 0.110). The relationship between running velocity and the energy cost of a 180°COD is best represented by a quadratic function (y = −0.012+0.066x +0.008x², [r = 0.994, p = 0.001]), but is also well represented by a linear (y = −0.228+0.152x, [r = 0.991, p<0.001]). These data suggest that even low running velocities have relatively high physiological demands if the COD frequency increases, and that running velocities affect the physiological demands of CODs. These results also showed that the energy expenditure of COD can be evaluated using only two data points. These results may be useful for estimating the energy expenditure of players during a match and designing shuttle exercise training programs.</p></div