Effects of energy loads on energy and nutrient absorption rates and gut microbiome in humans: A randomized crossover trial

OBJECTIVE

This study aimed to determine the effects of different energy loads on the gut microbiota composition and the rates of energy and nutrient excretion via feces and urine.

METHODS

A randomized crossover dietary intervention study was conducted with three dietary conditions: overfeeding (OF), control (CON), and underfeeding (UF). Ten healthy men were subjected to each condition for 8 days (4 days and 3 nights in nonlaboratory and laboratory settings each). The effects of dietary conditions on energy excretion rates via feces and urine were assessed using a bomb calorimeter.

RESULTS

Short-term energy loads dynamically altered the gut microbiota at the α-diversity (Shannon index), phylum, and genus levels (p < 0.05). Energy excretion rates via urine and urine plus feces decreased under OF more than under CON (urine -0.7%; p < 0.001, urine plus feces -1.9%; p = 0.049) and UF (urine -1.0%; p < 0.001, urine plus feces -2.1%; p = 0.031). However, energy excretion rates via feces did not differ between conditions.

CONCLUSIONS

Although short-term overfeeding dynamically altered the gut microbiota composition, the energy excretion rate via feces was unaffected. Energy excretion rates via urine and urine plus feces were lower under OF than under CON and UF conditions.

Evaluation of protein requirements using the indicator amino acid oxidation method: a scoping review

BACKGROUND

The indicator amino acid oxidation (IAAO) method has been accepted as an approach to evaluate habitual protein requirements under free-living conditions.

OBJECTIVES

This scoping review reports on literature that evaluated protein requirements in humans using the IAAO methods.

METHODS

Three databases (PubMed/Medline, Web of Science, and ProQuest) were systematically searched to identify studies that evaluated protein requirements using the IAAO method published in English until 5 June, 2023. We evaluated the study quality using previously developed criteria. We extracted the characteristics of the study design and the results of protein requirements. Two reviewers conducted both reviews and quality assessments independently; any differences among them were resolved by consensus or agreement of all team members.

RESULTS

We extracted 16 articles targeting children, young adults (including pregnant women, resistance training athletes, endurance-training athletes, and team sports), and older adults. In quality assessment, 14 studies were evaluated "strong," but the remaining 2 were "moderate." These studies were conducted in only 3 countries and did not include all sexes or life stages. The range of the estimated average protein requirements of each life stage was 1.30 g/kg body weight/d for children, 0.87 to 2.10 (0.87-0.93 for general young adults, 1.22-1.52 for pregnant women, 1.49-2.00 for resistance-trained athletes, 1.65-2.10 for endurance athletes, and 1.20-1.41 for team sports athletes) g/kg body weight/d for young adults, and 0.85 to 0.96 g/kg body weight/d for older adults.

CONCLUSIONS

Protein requirements in 14 studies were higher than the current reference for each sex, life stage, and physical activity that are related to protein requirements. In the future, protein requirements of various populations including sex and life stage could be assessed using the IAAO methods worldwide.

Effects of sleep restriction on food intake and appetite under free-living conditions: A randomized crossover trial

To investigate changes in subjective psychological factors and dietary intake during sleep restriction, we carried out a randomized crossover trial with a 3-day sleep restriction condition (SR; 5 h of sleep) and control sleep condition (CS; 8 h of sleep). Days 3 and 4 involved free-living and laboratory (in the morning) conditions, respectively. Subjective psychological factors (hunger, appetite, desire for sweets and fatty foods, sleepiness, and fatigue) were assessed using a 0.0-10.0 cm visual analog scale (VAS) every hour throughout the day on day 3, and at 8:00 a.m. on day 4. Dietary intake on day 3 was assessed on the basis of the food purchased and eaten. Fasting blood samples were collected at 8:00 a.m. on day 4. Dietary intake during the ad libitum breakfast was assessed on day 4. The participants were 13 women and 11 men (mean age, 21.4 ± 1.0 years; mean body mass index, 19.8 ± 1.7 kg/m2). The areas under the curve 0-16 h after waking for hunger, desire for fatty foods, sleepiness, and fatigue were higher in the SR than CS on day 3 (P < 0.05). Energy and carbohydrate intakes from snacks (daytime and nighttime) on day 3 were higher in the SR than CS (P < 0.05) but total dietary intake on day 3 was not different between the conditions (P > 0.05). The 2-arachidonoylglycerol level was different between the conditions (P < 0.05), but was not associated with sweet taste preference, dietary intake, or the active ghrelin level on day 4 (P > 0.05). In conclusion, ratings for subjective psychological factors and energy and carbohydrate intakes from snacks increased in association with sleep restriction under free-living conditions.

24-h glucose level and variability in response to carbohydrate overfeeding assessed using continuous glucose monitoring system are associated with daily carbohydrate intake

BACKGROUND & AIMS

The quantity gap between daily and loaded carbohydrates may affects blood glucose response to carbohydrate intake; however, no study has investigated the difference in 24-h span. This study aimed to determine differences in the 24-h glucose levels and variability in response to single-day carbohydrate overfeeding based on daily carbohydrate intake in healthy Japanese men.

METHODS

Twenty male college students completed a 3-day dietary record and were divided into two groups based on whether their daily carbohydrate intake exceeded the median intake (H-CHO) or not (L-CHO). Thereafter, the participants consumed a high-carbohydrate diet (carbohydrate 8.1 g/kg/d) for 1 day. The 24-h glucose levels and glucose variability (CONGA1) were measured using a continuous glucose monitoring system.

RESULTS

The mean daily carbohydrate intakes in the L-CHO and H-CHO groups were 3.9 ± 0.5 and 5.8 ± 0.6 g/kg/d, respectively (p < 0.001). The peak 24-h glucose level was not differ between the L-CHO group and the H-CHO group (8.0 ± 0.8 vs. 8.0 ± 1.0; p = 0.886). The mean 24-h glucose level was higher in the L-CHO group than in the H-CHO group (6.0 ± 0.3 vs. 5.6 ± 0.3 mmol/L; p = 0.010). The CONGA1 was higher in the L-CHO group than in the H-CHO group (5.40 ± 0.41 vs. 4.95 ± 0.25; p = 0.008).

CONCLUSIONS

Mean glucose level and glucose variability in response to carbohydrate overfeeding were high in the individuals with small daily carbohydrate intake. These findings suggest that the large quantity gap between daily and loaded carbohydrates cause worse glucose control during carbohydrate overfeeding.

Relationship between intra-individual variability in nutrition-related lifestyle behaviors and blood glucose outcomes under free-living conditions in adults without type 2 diabetes

AIMS

This study determined the relationship between intra-individual variability in day-to-day nutrition-related lifestyle behaviors (meal timing, eating window, food intake, movement behaviors, sleep conditions, and body weight) and glycemic outcomes under free-living conditions in adults without type 2 diabetes.

METHODS

We analyzed 104 adults without type 2 diabetes. During the 7-day measurement period, dietary intake, movement behaviors, sleep conditions, and glucose outcomes were assessed. Daily food intake was assessed using a mobile-based health application. Movement behaviors and sleep conditions were assessed using a tri-axial accelerometer. Meal timing was assessed from the participant's daily life record. Blood glucose levels were measured continuously using a glucose monitor. Statistical analyses were conducted using a linear mixed-effects model, with mealtime, food intake, body weight, movement behaviors, and sleep conditions as fixed effects and participants as a random effect.

RESULTS

Dinner time and eating window were positively significantly correlated with mean (dinner time, p = 0.003; eating window, p = 0.001), standard deviation (SD; both at p < 0.001), and maximum (both at p < 0.001) blood glucose levels. Breakfast time was negatively associated with glucose outcomes (p < 0.01). Sedentary time was positively significantly associated with blood glucose SD (p = 0.040). Total sleep time was negatively significantly correlated with SD (p = 0.035) and maximum (p = 0.032) blood glucose levels. Total daily energy intake (p = 0.001), carbohydrate intake (p < 0.001), and body weight (p < 0.05) were positively associated with mean blood glucose levels.

CONCLUSION

Intra-individual variations in nutrition-related lifestyle behaviors, especially morning and evening body weight, and food intake, were associated with mean blood glucose levels, and a long sedentary time and total sleep time were associated with glucose variability. Earlier dinner times and shorter eating windows per day resulted in better glucose control.

Delayed Eating Schedule Raises Mean Glucose Levels in Young Adult Males: a Randomized Controlled Cross-Over Trial

BACKGROUND

Misalignment of meals to the biological clock may cause adverse effects on glucose metabolism. However, the effects of repeated different eating schedules (early compared with late) on glucose concentration throughout the day are poorly understood.

OBJECTIVES

We examined the effects of different eating schedules on the 24-h glucose response using a continuous glucose monitor (CGM).

METHODS

Eight young adult males (age, 20.9 ± 3.4 y; body mass index: 21.3 ± 1.8 kg/m²) each followed 2 different eating schedules (early [08:30, 13:30, and 19:30] and late [12:00, 17:00, and 23:00]) in random order. These diet interventions were conducted for 8 d, with an experimental period of 3 d and 2 nights (from dinner on day 7) after 7 d of free living. The 3 meals in each intervention were nutritionally equivalent (55% carbohydrate, 15% protein, and 30% fat). The 24-h mean interstitial glucose concentration on day 8 was obtained under controlled conditions using the CGM (primary outcome). These concentrations were compared among the following 3 schedules using Dunnett's test, with the early eating schedule as reference (1 compared with 2 and 1 compared with 3): 1) early eating schedule (control), 2) late eating schedule according to the clock time (08:00 on day 8 to 08:00 on day 9), and 3) late eating schedule according to the time elapsed since the first meal for 24 h.

RESULTS

The 24-h mean ± SD interstitial glucose concentrations when participants followed the late eating schedule were higher than those when they followed the early eating schedule in terms of clock time (91.2 ± 2.9 compared with 99.2 ± 4.6 mg/dL, P = 0.003) and time elapsed (91.2 ± 2.9 compared with 98.3 ± 3.8 mg/dL, P < 0.001).

CONCLUSIONS

A late eating schedule increases the mean 24-h interstitial glucose concentration in young adult males. This insight will have useful implications in determining meal timings, especially for those with conditions such as diabetes.

Association of the interaction between physical activity and sitting time with mortality in older Japanese adults

PURPOSE

To examine how physical activity (PA) and sitting time (ST) are associated with mortality in older Japanese adults.

METHODOLOGY

We used the data of 10 233 older Japanese adults aged ≥65 years who provided valid responses to the International Physical Activity Questionnaire-Short Form (IPAQ-SF) by a mail survey. Both PA and ST were assessed using the IPAQ-SF. The results were classified into high or low categories using ≥3.0 metabolic equivalent PA (150 min/week) and ST (300 min/day) into the following four groups: High PA (HPA)/Low ST (LST), HPA/High ST (HST), Low PA (LPA)/LST, and LPA/HST. Mortality data were collected from July 30, 2011, to November 30, 2016. We assessed the interaction of PA and ST status with the risk of all-cause mortality using the multivariable Cox proportional-hazards model.

RESULTS

A total of 1014 people were recorded to have died during a median follow-up period of 5.3 years (51 553 person-years). After adjustment for confounders, the risk of mortality was higher in the LPA/HST group than in all other groups (HPA/LST: reference; HPA/HST group: hazard ratio [HR] 0.86 (95% confidence interval [CI]: 0.66 to 1.12); LPA/LST group: HR 1.09 (95% CI: 0.88 to 1.35); LPA/HST group: HR 1.36 (95% CI: 1.10 to 1.67); and multiplicative interaction: HR 1.44 (95% CI: 1.07 to 1.94)).

CONCLUSIONS

The risk of mortality associated with LPA/HST depends on the level of PA, duration of ST, and their interaction with each other. Our results may be useful in ameliorating the adverse effects leading to mortality in individuals with lower PA, by reducing ST.

Association between skeletal muscle mass or percent body fat and metabolic syndrome development in Japanese women: A 7-year prospective study

Previous cross-sectional studies have indicated that low relative appendicular lean mass (ALM) against body weight (divided by body weight, ALM/Wt, or divided by body mass index, ALM/BMI) was negatively associated with metabolic syndrome (MetS). Conversely, previous cross-sectional studies have indicated that the absolute ALM or ALM divided by squared height (ALM/Ht2) were positively associated with MetS. The aim of this longitudinal study was to investigate the association between low absolute or relative skeletal muscle mass, leg muscle power, or percent body fat and the development of MetS in Japanese women in a 7-y prospective study. The study participants included 346 Japanese women aged 26 to 85 years. The participants were divided into low and high groups based on the median values of ALM/Wt, ALM/BMI, ALM/Ht2, absolute ALM, or leg power. The longitudinal relationship between ALM indices or leg power and MetS development was examined using Kaplan-Meier curves and Cox regression models (average follow-up duration 7 years, range 1 to 10 years). During follow-up, 24 participants developed MetS. MetS incidence was higher in the low ALM/Wt group than the high ALM/Wt group even after controlling for age, obesity, waist circumference, family history of diabetes, smoking, and physical activity [adjusted hazard ratio = 5.60 (95% CI; 1.04-30.0)]. In contrast, MetS incidence was lower in the low ALM/Ht2 group than the high ALM/Ht2 group [adjusted hazard ratio = 10.6 (95%CI; 1.27-89.1)]. MetS incidence was not significantly different between the low and high ALM/BMI, absolute ALM, and leg power groups. Both ALM/Ht2 and ALM/Wt were not significant predictive variables for MetS development when fat mass or percent body fat was taken into account in the Cox model. At the very least, the results of this study underscore the importance of body composition measurements in that percent body fat, but not ALM, is associated with MetS development.

Determination of Optimal Daily Magnesium Intake among Physically Active People: A Scoping Review

Little is known about the optimal daily magnesium (Mg) intake for individuals with high levels of physical activity. The aim of this study was to clarify the optimal dietary Mg intake for people with high levels of physical activity in a scoping review. In this review, we searched MEDLINE and Japan Medical Abstracts Society for studies published up to May 31, 2020. We conducted two searches, one for studies using gold standard measurement methods such as the balance method and factorial calculation (Search 1), and the other for studies using estimation from daily food intake (Search 2). We also performed a meta-analysis of studies that compared the Mg intake among physically active people with the Mg intake among controls. After the primary and secondary screening, 31 studies were included in the final review. All of the included studies examined professional or recreational athletes. We found no studies that examined the optimal intake of Mg using gold standard measurement methods. The Mg intake among physically active individuals was below the recommended dietary allowance in most studies. In five studies that conducted meta-analyses, physically active individuals had significantly higher intakes of Mg than controls, although these levels were still below the recommended dietary allowance. The present review revealed that evidence regarding the optimal daily magnesium intake is currently scarce, and further studies are needed.

Olfaction, ability to identify particular olfactory clusters and odors, and physical performance in community-dwelling older adults: The Yanai Study

BACKGROUND

Olfactory dysfunction is associated with poor physical performance in older adults. However, it remains unknown whether the ability to identify particular olfactory clusters and/or odors is associated with physical performance in physically independent community-dwelling older adults.

METHODS

This cross-sectional study included 130 community-dwelling older adults (70.1 ± 5.5 years). The Odor Stick Identification Test for Japanese people, consisting of 12 odors in four clusters (wood, grass, herb; sweet; spices; foul-smelling), was used to examine olfaction. Participants also completed physical performance tests (one leg standing with open eyes; aerobic capacity; lower muscle function: five-times chair stand [CS] and vertical jump; mobility: star walking and timed up and go [TUG]) and cognitive function tests.

RESULTS

Worse overall olfaction was not significantly associated with any physical performance measure. Worse performance for identifying sweet odors and an inability to identify some specific odors (menthol and rose) were associated with worse mobility and/or lower muscle function-adjusted covariates. Moreover, an inability to identify menthol and rose was associated with worse TUG (odds ratio [OR]: 0.424; 95% confidence interval [CI]: 0.215-0.836), star walking (OR: 0.714; 95% CI: 0.506-0.976), CS (OR: 0.638; 95% CI: 0.470-0.864), and vertical jump (OR: 1.12; 95% CI: 1.001-1.24) performance, even when the analysis was adjusted to exclude menthol and rose score from the overall olfaction score (p < .05 for all).

CONCLUSIONS

The current study may help to increase awareness of olfactory and physical dysfunction at an earlier stage among physically independent community-dwelling older adults.

Impact of walking aids on estimating physical activity using a tri-axial accelerometer in frail older adults

Objectives

This study aimed to compare the estimation error of physical activity level (PAL) estimated using a tri-axial accelerometer between an independent walking group and an assisted walking group with walking aids.

Methods

Subjects were 6 older adults who could walk independently and 10 older adults requiring walking assistance during gait. Total energy expenditure (TEE) was measured using the doubly labelled water (DLW) method over 2 weeks and PAL was calculated as the measured TEE divided by the basal metabolic rate measured using indirect calorimetry (PAL_DLW). The participants wore a tri-axial accelerometer (Active style Pro HJA-750C) on the waist simultaneously as the DLW period, and the estimated PAL was derived from it (PAL_ACC).

Results

The median PAL estimation error in the assisted walking group was −0.30 kcal/day (range: −0.77 to −0.01 kcal/day) and more underestimated than that in the independent walking group (p=0.02). The estimation error of PAL_ACC was significantly correlated with PAL_DLW (r=−0.80, p<0.01).

Conclusions

Using the accelerometer, PAL was underestimated for older adults who used walking aids but not for those who walked independently under free-living conditions.

The effects of breaking sedentary time with different intensity exercise bouts on energy metabolism: A randomized cross-over controlled trial

BACKGROUND AND AIMS

Breaking up sedentary periods, particularly with light activity, increases total energy expenditure (EE), and helps provide better glycemic control. However, the effects of activities of various intensities to interrupt prolonged sedentary time are unclear. The purpose of the present study was to examine potential differences in glycemic control and EE from breaking up sedentary time with short exercise bouts of different intensities.

METHODS AND RESULTS

Nine overweight/obesity young men underwent whole body indirect calorimetry at 19:00 on day 1 and stayed overnight. After awakening on day 2, they performed short duration jogging every 30 min over 8 h (16-time bouts in total) under 3 different conditions with the same running distance: (1) lactate threshold (LT) for 2 min, (2) 60% LT for 200 s, and (3) onset of blood lactate accumulation (OBLA) for 75 s. The 24-h EE and interstitial glucose concentration (from 8:00 to 19:00 on day 2) was continuously measured throughout the trials. The standard deviation during intervention and indexes of postprandial of the interstitial glucose concentration was significantly lower at LT and OBLA than at 60% LT (p < 0.05). The 24-h EE was not significantly different among conditions, but EE at OBLA during intervention was slightly but significantly higher than at 60% LT and LT.

CONCLUSION

Breaking up sedentary time with short-duration jogging at LT and with OBLA intensities may have better glycemic control and increased use of carbohydrate as a fuel, while short-duration a jogging at OBLA intensity may increase EE.

TRIAL REGISTRATION

UMIN000041361.

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.

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.

Room Indirect Calorimetry Operating and Reporting Standards (RICORS 1.0): A Guide to Conducting and Reporting Human Whole-Room Calorimeter Studies

Whole-room indirect calorimeters have been used to study human metabolism for more than a century. These studies have contributed substantial knowledge to the assessment of nutritional needs and the regulation of energy expenditure and substrate oxidation in humans. However, comparing results from studies conducted at different sites is challenging because of a lack of consistency in reporting technical performance, study design, and results. In May 2019, an expert panel was convened to consider minimal requirements for conducting and reporting the results of human whole-room indirect calorimeter studies. We propose Room Indirect Calorimetry Operating and Reporting Standards, version 1.0 (RICORS 1.0) to provide guidance to ensure consistency and facilitate meaningful comparisons of human energy metabolism studies across publications, laboratories, and clinical sites.

Breakfast skipping is related to inadequacy of vitamin and mineral intakes among Japanese female junior high school students: a cross-sectional study

Breakfast skipping is a public health issue which affects nutrient intake among adolescents worldwide. However, there have been few reports comparing intake and reference values to assess the deficiency of nutrient intake between breakfast consumers and skippers. Therefore, the present study aimed to examine the relationship between breakfast skipping and adequacy of total habitual nutrient intake among junior high school female students. The participants were 516 Japanese female junior high school students. Dietary habits during the preceding month were assessed using a brief self-administered diet history questionnaire. Inadequacy of each nutrient intake was assessed by the cut-point method, based on the estimated average requirement for fourteen nutrients and on dietary goal values for five nutrients. The overall nutritional inadequacy in participants was assessed by the number of consumed nutrients which did not meet the requirements as per the dietary reference intakes for Japanese, 2015 version. The participants were classified into two groups according to the frequency of breakfast eating: breakfast consumers (seven times/week) and breakfast skippers (0-6 times/week). Adequacy of vitamin A, vitamin B1, vitamin B2, vitamin C, Ca, Fe, Zn and K was higher among breakfast consumers than among skippers. Breakfast consumers had more intakes of fruits, vegetables and dairy products. Our findings suggest that breakfast skipping was related to deficiencies in vitamin and mineral intakes, and to an unfavourable dietary pattern, among Japanese female junior high school students.

Acute Sleep Curtailment Increases Sweet Taste Preference, Appetite and Food Intake in Healthy Young Adults: A Randomized Crossover Trial

This study aimed to examine the effect of acute sleep curtailment on sweet taste preference, appetite and food intake, and the correlation between food intake and sweet taste preference or active ghrelin using a randomized crossover design (5 h sleep curtailment vs. 8 h control). Twenty-four participants (11 men) aged 21.4 ± 1.0 years, with BMI 19.8 ± 1.7 kg/m², who habitually slept 5 h/night or more experienced interventions lasting three consecutive nights. Participants came into the laboratory for testing on day 4. Fasting blood tests were conducted at 8:00 a.m. to measure active ghrelin and leptin levels. Sweet taste preference was assessed by presenting five different concentration sucrose solutions at 9:00 a.m. Ad libitum intake at breakfast was assessed for 30 min from 9:30 a.m. Sweet taste preference was higher following sleep curtailment than control. Active ghrelin was likewise higher following sleep curtailment than control. Leptin did not differ between conditions. Energy intake was higher following sleep curtailment than control, being derived primarily from carbohydrates. However, sweet taste preference and active ghrelin did not correlate with energy intake. These results suggest that acute consecutive sleep curtailment increases sweet taste preference, active ghrelin, and energy intake in healthy young adults.

Physical Activity and/or High Protein Intake Maintains Fat-Free Mass in Older People with Mild Disability; the Fukuoka Island City Study: A Cross-Sectional Study

Body composition changes with age, with fat mass (FM) increasing and fat-free mass (FFM) decreasing. Higher physical activity and high or adequate protein intake are thought to be beneficial in preventing the loss of skeletal muscle mass in the elderly. We aimed to investigate the relationships between physical activity, protein intake, and FFM in older people with mild disability. Total energy expenditure (TEE) under free-living conditions was assessed using the doubly-labelled water (DLW) method, and physical activity was measured using a triaxial accelerometer. Dietary intake was assessed using a self-recorded food intake diary during the DLW period. Percent FFM was significantly positively correlated with protein intake and physical activity level (PAL) after adjustment for age and sex (protein intake r = 0.652, p < 0.001, PAL r = 0.345, p = 0.011). In multiple linear regression analysis, when PAL, moderate-to-vigorous physical activity (MVPA), or protein intake were included, 31%, 32%, and 55%, respectively, of the variation in %FFM was explained. Moreover, the addition of both PAL/MVPA and protein intake explained 61%/60%, respectively, of the variation in %FFM. Either protein intake above the currently recommended level or higher levels of physical activity would be beneficial for the maintenance of high %FFM.

Effect of exercise timing on elevated postprandial glucose levels

There is no consensus regarding optimal exercise timing for reducing postprandial glucose (PPG). The purpose of the present study was to determine the most effective exercise timing. Eleven participants completed four different exercise patterns 1) no exercise; 2) preprandial exercise (jogging); 3) postprandial exercise; and 4) brief periodic exercise intervention (three sets of 1-min jogging + 30 s of rest, every 30 min, 20 times total) in a random order separated by a minimum of 5 days. Preprandial and postprandial exercise consisted of 20 sets of intermittent exercise (1 min of jogging + 30 s rest per set) repeated 3 times per day. Total daily exercise volume was identical for all three exercise patterns. Exercise intensities were 62.4 ± 12.9% V̇o2peak. Blood glucose concentrations were measured continuously throughout each trial for 24 h. After breakfast, peak blood glucose concentrations were lower with brief periodic exercise (99 ± 6 mg/dl) than those with preprandial and postprandial exercise (109 ± 10 and 115 ± 14 mg/dl, respectively, P < 0.05, effect size = 0.517). After lunch, peak glucose concentrations were lower with brief periodic exercise than those with postprandial exercise (97 ± 5 and 108 ± 8 mg/dl, P < 0.05, effect size = 0.484). After dinner, peak glucose concentrations did not significantly differ among exercise patterns. Areas under the curve over 24 h and 2 h postprandially did not differ among exercise patterns. These findings suggest that brief periodic exercise may be more effective than preprandial and postprandial exercise at attenuating PPG in young active individuals.

NEW & NOTEWORTHY This was the first study to investigate the effect of different exercise timing (brief periodic vs. preprandial vs. postprandial exercise) on postprandial glucose (PPG) attenuation in active healthy men. We demonstrated that brief periodic exercise attenuated peak PPG levels more than preprandial and postprandial exercise, particularly in the morning. Additionally, PPG rebounded soon after discontinuing postprandial exercise. Thus, brief periodic exercise may be better than preprandial and postprandial exercise at attenuating PPG levels.

"Slow walking with turns" increases quadriceps and erector spinae muscle activity

[Purpose] To maintain an independent lifestyle, older adults should improve muscle strength and mass, or aerobic capacity. A new exercise pattern, called slow walking with turns, which incorporates turning as an extra load additional to walking. The purpose of this study was to measure oxygen consumption during exercise and muscle activity while turning. [Subjects and Methods] Recreationally active volunteers participated. The participants performed 20 turns per minute while walking back and forth over distances of 1.5 to 3.5 m. We measured oxygen consumption, heart rate, and rating of perceived exertion and performed electromyography during the exercise. [Results] The metabolic equivalents of the exercise were 4.0 ± 0.4 to 6.3 ± 4.0 Mets. Activity was significantly greater in the vastus medialis, vastus lateralis, and erector spinae during the turn phase of slow walking with turns than during the stance phase of treadmill walking. [Conclusion] These findings suggest that slow walking with turns may help to preserve the muscle strength and mass of the trunk and lower limbs that are needed to maintain an independent lifestyle. Slow walking can be performed easily by older people, and in slow walking with turns, the exercise intensity can be adjusted as required for each individual.

A novel approach for measuring energy expenditure of a single sit-to-stand movement

PURPOSE

The purpose of this study was to quantify the energy expenditure (EE) of a sit-to-stand (STS) movement using a recently developed method and to examine the relationship between physical characteristics and the physiological demands of STS.

METHODS

Nineteen participants completed a multi-stage test at different STS frequencies of 6, 10, 15, 20 and 30 repetitions per minute. The expired gas, heart rate (HR) and rating of perceived exertion (RPE) were measured. The relationship between EE and STS frequency was obtained and the slope of the regression was quantified as the EE of an STS.

RESULTS

The gross EE and HR increased linearly as the STS frequency increased in all participants. The net EE of an STS was 0.92 ± 0.37 kJ. The EE of an STS increased as the height and weight increased, and these relationships were well fit by quadratic regression. The metabolic equivalent (Met) of performing 15 STSs per minute was 4.3 ± 1.0 Mets and RPE was 12 ± 1 over a total of 20.

CONCLUSION

This study demonstrated that the EE of an instantaneous movement can be quantified by relating the gross EE and different frequencies of movement. Using this method, we quantified the EE of an STS, which varied depending on participants' anthropometrics. Mets of repetitive STS movement ranged from 2.6 to 7.2. This physiological profile is useful when performing repetitive STS movements as a form of exercise.

Measurement of body composition in response to a short period of overfeeding

Background

Obesity and overweight are increasing in prevalence in developed countries as a result of changing dietary habits and a lack of physical activity. The purpose of the present study was to evaluate the changes in body composition during short-term overfeeding using the three-component model, which is composed of fat mass (FM), total body water (TBW), and fat-free dry solids (FFDS).

Methods

Ten healthy men completed 3 days of overfeeding during which they consumed 1,500 kcal/day more energy than consumed in their normal diets. Body composition was evaluated at three time points: the day before and after their normal diets and the day after the 3-day overfeeding diet.

Results

Before and after their normal diets, there were no significant differences in body weight and composition, but after 3 days of overfeeding, body weight, TBW, and FFDS increased 0.7, 0.7, and 0.2 kg, respectively (P <0.0001). There was no significant difference in FM between the normal and overfeeding diets.

Conclusion

This study suggests that TBW gain contributes to weight gain following a short-term overfeeding.

The relationship between running velocity and the energy cost of turning during running

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.

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.

A novel method for calculating the energy cost of turning during running

Although changes of direction are one of the essential locomotor patterns in ball sports, the physiological demand of turning during running has not been previously investigated. We proposed a novel approach by which to evaluate the physiological demand of turning. The purposes of this study were to establish a method of measuring the energy expenditure (EE) of a 180° turn during running and to investigate the effect of two different running speeds on the EE of a 180° turn. Eleven young, male participants performed measurement sessions at two different running speeds (4.3 and 5.4 km/hour). Each measurement session consisted of five trials, and each trial had a different frequency of turns. At both running speeds, as the turn frequency increased the gross oxygen consumption (V·O₂) also increased linearly (4.3 km/hour, r = 0.973; 5.4 km/hour, r = 0.996). The V·O₂ of a turn at 5.4 km/hour (0.55 [SD 0.09] mL/kg) was higher than at 4.3 km/hour (0.34 [SD 0.13] mL/kg) (P < 0.001). We conclude that the gross V·O₂ of running at a fixed speed with turns is proportional to turn frequency and that the EE of a turn is different at different running speeds. The Different Frequency Accumulation Method is a useful tool for assessing the physiological demands of complex locomotor activity.

Validation of Web-based physical activity measurement systems using doubly labeled water

BACKGROUND

Online or Web-based measurement systems have been proposed as convenient methods for collecting physical activity data. We developed two Web-based physical activity systems-the 24-hour Physical Activity Record Web (24hPAR WEB) and 7 days Recall Web (7daysRecall WEB).

OBJECTIVE

To examine the validity of two Web-based physical activity measurement systems using the doubly labeled water (DLW) method.

METHODS

We assessed the validity of the 24hPAR WEB and 7daysRecall WEB in 20 individuals, aged 25 to 61 years. The order of email distribution and subsequent completion of the two Web-based measurements systems was randomized. Each measurement tool was used for a week. The participants' activity energy expenditure (AEE) and total energy expenditure (TEE) were assessed over each week using the DLW method and compared with the respective energy expenditures estimated using the Web-based systems.

RESULTS

The mean AEE was 3.90 (SD 1.43) MJ estimated using the 24hPAR WEB and 3.67 (SD 1.48) MJ measured by the DLW method. The Pearson correlation for AEE between the two methods was r = .679 (P < .001). The Bland-Altman 95% limits of agreement ranged from -2.10 to 2.57 MJ between the two methods. The Pearson correlation for TEE between the two methods was r = .874 (P < .001). The mean AEE was 4.29 (SD 1.94) MJ using the 7daysRecall WEB and 3.80 (SD 1.36) MJ by the DLW method. The Pearson correlation for AEE between the two methods was r = .144 (P = .54). The Bland-Altman 95% limits of agreement ranged from -3.83 to 4.81 MJ between the two methods. The Pearson correlation for TEE between the two methods was r = .590 (P = .006). The average input times using terminal devices were 8 minutes and 10 seconds for the 24hPAR WEB and 6 minutes and 38 seconds for the 7daysRecall WEB.

CONCLUSIONS

Both Web-based systems were found to be effective methods for collecting physical activity data and are appropriate for use in epidemiological studies. Because the measurement accuracy of the 24hPAR WEB was moderate to high, it could be suitable for evaluating the effect of interventions on individuals as well as for examining physical activity behavior.