Makoto Ayabe

The use of uniaxial accelerometry for the assessment of physical-activity-related energy expenditure: a validation study against whole-body indirect calorimetry.

Assessing the total energy expenditure (TEE) and the levels of physical activity in free-living conditions with non-invasive techniques remains a challenge. The purpose of the present study was to investigate the accuracy of a new uniaxial accelerometer for assessing TEE and physical-activity-related energy expenditure (PAEE) over a 24 h period in a respiratory chamber, and to establish activity levels based on the accelerometry ranges corresponding to the operationally defined metabolic equivalent (MET) categories. In study 1, measurement of the 24 h energy expenditure of seventy-nine Japanese subjects (40 (SD 12) years old) was performed in a large respiratory chamber. During the measurements, the subjects wore a uniaxial accelerometer (Lifecorder; Suzuken Co. Ltd, Nagoya, Japan) on their belt. Two moderate walking exercises of 30 min each were performed on a horizontal treadmill. In study 2, ten male subjects walked at six different speeds and ran at three different speeds on a treadmill for 4 min, with the same accelerometer. O2 consumption was measured during the last minute of each stage and was expressed in MET. The measured TEE was 8447 (SD 1337) kJ/d. The accelerometer significantly underestimated TEE and PAEE (91.9 (SD 5.4) and 92.7 (SD 17.8) % chamber value respectively); however, there was a significant correlation between the two values (r 0.928 and 0.564 respectively; P<0.001). There was a strong correlation between the activity levels and the measured MET while walking (r(2) 0.93; P<0.001). Although TEE and PAEE were systematically underestimated during the 24 h period, the accelerometer assessed energy expenditure well during both the exercise period and the non-structured activities. Individual calibration factors may help to improve the accuracy of TEE estimation, but the average calibration factor for the group is probably sufficient for epidemiological research. This method is also important for assessing the diurnal profile of physical activity.

Long-period accelerometer monitoring shows the role of physical activity in overweight and obesity

CONTEXT:Physical activity (PA) plays an important role in obesity. A new accelerometer has been developed to assess total energy expenditure as well as PA.OBJECTIVE:To investigate the association of PA with overweight and obesity in Japanese men and women, a large cross-sectional study was performed using a single-axis accelerometer.DESIGN, SETTING AND PARTICIPANTS:Population-based cross-sectional study of Japanese 18–84 y of age. Height, body weight and PA were measured in 400 male and 388 female Japanese volunteers from 1999 to 2000. The outcome measurements were overweight and obesity, which are defined as a body mass index ≥25 kg/m2. PA was measured for 1 to 4 weeks and was then categorized into three activity levels, which were defined as light, moderate and vigorous PA.RESULTS:Prevalence of overweight and obesity was 22.3%. Number of steps and time spent in moderate and vigorous PA per day were lower in overweight and obese individuals. No difference was found in time spent in light PA. Individuals who are in the 4th and 5th quintile of moderate and vigorous PA showed a significantly lower body mass index. When odd ratios (ORs) of overweight and obesity estimated by logistic regression were used as effect measures, overweight and obesity were negatively associated with vigorous PA (ORs=0.91).CONCLUSION:These results indicate that overweight and obese individuals have a lower step rate and are spending less time for moderate to vigorous PA. Participation in vigorous PA is an important predictor of overweight and obesity.

Comparison of interdevice measurement difference of pedometers in younger and older adults

Objectives In this study, the relationship between inter-instrument differences in regard to the daily number of steps with the intensity distribution of daily physical activity in younger and older adults was examined. Methods 17 younger individuals and 28 older individuals wore two pedometers (Lifecorder (LC) and EC-200 (YM)) simultaneously for 7 days, in order to determine the number of steps each took. Furthermore, LC determined the time spent in light, moderate and vigorous physical activity, corresponding to <3 metabolic equivalent (METs), 3 to 6 METs and >6 METs, respectively. Results The LC detected a significantly larger number of steps than YM (p<0.001), yet there was a strong relationship between the two measurements (r = 0.962, p<0.001). The interdevice difference with the number of steps significantly decreased in inactive older individuals compared with the active older and younger individuals, and it was also significantly negatively correlated with the time spent in light-intensity physical activity (LPA) (r = 0.523, p<0.01). Conclusion This study showed that the interdevice difference with the number of steps significantly increased in older participants due to the greater length of time spent in LPAs.

Lifestyle Intervention Involving Calorie Restriction with or without Aerobic Exercise Training Improves Liver Fat in Adults with Visceral Adiposity

Objective. To evaluate the effect of calorie restriction-induced weight loss with or without aerobic exercise on liver fat. Methods. Thirty-three adults with visceral adiposity were divided into calorie restriction (CR; n = 18) or CR and aerobic exercise (CR + Ex; n = 15) groups. Target energy intake was 25 kcal/kg of ideal body weight. The CR + Ex group had a targeted exercise time of 300 min/wk or more at lactate threshold intensity for 12 weeks. Results. Reductions in body weight (CR, −5.3 ± 0.8 kg; CR + Ex, −5.1 ± 0.7 kg), fat mass (CR, −4.9 ± 0.9 kg; CR + Ex, −4.4 ± 0.6 kg), and visceral fat (CR, −24 ± 5 cm2; CR + Ex, −37 ± 5 cm2) were not statistically different between groups. Liver fat decreased significantly in both groups, with no difference between groups. Change in maximal oxygen uptake was significantly greater in the CR + Ex group than in the CR group (CR, −0.7 ± 0.7 mL/kg/min; CR + Ex, 2.9 ± 1.0 mL/kg/min). Conclusion. Both CR and CR + Ex resulted in an improved reduction in liver fat; however, there was no additive effect of exercise training.

Physical Function Is Weakly Associated with Angiotensin-Converting Enzyme Gene I/D Polymorphism in Elderly Japanese Subjects

Background: The turning point in the deterioration of physical function seems to occur between the ages of 70 and 80 years. In particular, muscle strength may decline even more in subjects older than 75. A recent study found that the angiotensin-converting enzyme (ACE) genotype also affects physiological left ventricular hypertrophy. A very limited number of papers have examined genetic differences in resistance and endurance forms of a single sporting discipline. Objective: The purpose of this study was to evaluate the relationship between ACE genotype and physical function by controlling the known confounding factors including dental status. Methods:We selected 431 subjects who were aged 76 years and did not require special care for their daily activities. We conducted a medical examination, followed by 5 physical function tests, as follows: (1) maximum hand grip strength, (2) maximal isometric knee extensor strength, (3) maximal stepping rate for 10 s, (4) one-leg standing time with eyes open and (5) 10-meter maximum walking speed. Subjects were genotyped for the ACE intron 16 Alu insertion. In addition, serum concentrations of total cholesterol, total protein, IgA and IgG were measured at a commercial laboratory. The Eichner index was used as an indicator of occlusal condition. Multiple linear regression analysis was performed to evaluate the relationship between the ACE gene insertion/deletion (I/D) polymorphism and physical function considering confounding factors. Results: The ACE gene I/D polymorphism was positively associated with hand grip strength and 10-meter maximum walking speed. Betas of hand grip strength were 0.09 for I/D (p = 0.022) and 0.12 for insertion/insertion (I/I; p = 0.004). Betas of 10-meter walking speed were –0.11 for I/D (p = 0.093) and –0.14 for I/I (p = 0.039). Dental status such as Eichner index class C was significantly associated with one-leg standing time with eyes open (beta –0.11; p = 0.028). Conclusion: This study suggests that there is a significant relationship between ACE genotype and physical function. In particular, subjects with the ACE deletion/deletion genotype were associated with upper extremities.

Self-monitoring moderate-vigorous physical activity versus steps/day is more effective in chronic disease exercise programs.

PURPOSE The effects of self-monitoring number of steps/day versus minutes of moderate to vigorous-intensity physical activity (MVPA/day) were compared to determine which is more effective for increasing physical activity levels. METHODS A total of 18 participants of a university-based chronic disease prevention program (age 61 ± 12 years) were enrolled in the 3-week intervention. Subjects were randomly assigned to a group (n = 8) that wore a New Lifestyles accelerometer (NL-1000) and were instructed to increase minutes of MVPA to 30 min/d or more (MIN) or to a group (n = 10) that wore a New Lifestyles pedometer (NL-800) and were instructed to increase the number of steps/day to 10,000 or more (STE). To objectively assess changes in physical activity levels, subjects in both groups simultaneously wore a Lifecorder-EX accelerometer (with display blank) during the intervention. RESULTS The number of steps increased significantly in the MIN (10,810 ±3,211 to 13,355 ± 3,498 steps/day) and STE (11,517 ± 3,383 to 12,809 ±2,479 steps/day) from the first to fourth weeks, respectively. However, the time spent in MVPA increased significantly only in MIN group (36 ± 11 to 52 ± 15 min/d) but not in the STE group (32 ± 7 to 37 ± 11 min/d) from the first to fourth weeks, respectively. CONCLUSION Data suggest that individuals with chronic disease conditions can more effectively increase levels of physical activity, expressed as both MVPA/day and steps/day, by self-monitoring MIN rather than STE. The effect of self-monitoring physical activity levels for longer periods and/or the effect of increasing minutes of MVPA/day versus steps/day on specific health outcomes have not yet been examined.

Minor effects of green tea catechin supplementation on cardiovascular risk markers in active older people: a randomized controlled trial.

Aim:  Although previous studies have shown that consumption of green tea catechins (GTC) and walking might prevent development of cardiovascular disease (CVD), the effects of GTC supplementation on CVD risk in active older people are unknown.

Epoch length and the physical activity bout analysis: An accelerometry research issue

BackgroundThe purpose of the present investigation was to compare the bouts of daily physical activity (PA) determined by three different accelerometer epoch lengths under free-living conditions.MethodsOne hundred thirty-four adults (50 ± 7 years) wore an accelerometer (Lifecorder) for 7 consecutive days under free-living conditions in order to determine the time spent in physical activity of light intensity (LPA), moderate intensity (MPA), vigorous intensity (VPA), moderate to vigorous intensity (MVPA), and the total physical activity (TPA; sum of LPA, MPA and VPA). Additionally, all PA was divided according to the bout durations (sporadic, >3 min, >5 min, and > 10 min). These indices of PA were analyzed using three different epoch lengths (4 sec, 20 sec and 60 sec) derived from the accelerometer.ResultsThe LPA significantly increased in association with increases in the epoch length (48.7 ± 15.9 to 178.7 ± 62.6 min/day, p < 0.05). The amount of sporadic VPA determined by the shortest epoch length (2.9 ± 5.2 min/day) was significantly longer than the two remaining epoch lengths (1.1 ± 2.4 to 0.9 ± 2.5 min/day, p < 0.05). The times of the MVPA bouts lasting longer than 3 minutes determined using the 4-second epoch length (2.6 ± 5.4 to 7.7 ± 10.0 min/day) were significantly shorter than those determined using the other two settings (6.5 ± 10.5 to 13.8 ± 13.8 min/day, p < 0.05). The frequencies of the MVPA bouts lasting longer than 10 minutes determined using the 4-second epoch length (0.2 ± 0.3 bouts/day) were significantly lower than those determined using the other two settings (0.3 ± 0.4 bouts/day, p < 0.05).ConclusionThe epoch length setting of the accelerometer affects the estimation of the PA bouts under free-living conditions in middle-aged to older adults.

Accumulation of short bouts of non-exercise daily physical activity is associated with lower visceral fat in Japanese female adults.

The purpose of the present investigation was to assess the relationship between bouts of very short daily physical activity (PA) lasting <10 min with obesity and abnormal fat distributions. A total of 42 females (age 50±6 years, height 156±5 cm, body weight 54±8 kg, body mass index 22±3 kg/m2) participated in the present investigation. Computed tomography was used to evaluate the area of visceral adipose tissue and subcutaneous adipose tissue (VAT and SAT). All participants wore a pedometer with a one-axial accelerometer (Lifecorder, Kenz, Japan) in order to determine their frequency (bouts/day) of PA and moderate to vigorous intensity PA (MVPA). The total frequency of PA and MVPA, including all bout durations, was not significantly associated with the body fat distribution. The frequency of PA lasting longer than 3 min and 5 min, and MVPA lasting longer than 1 min and 3 min were significantly associated with the area of the VAT (p<0.05). A smaller area of VAT was associated with a higher frequency of PA and MVPA lasting 1-5 min. The present investigation did not find that very short bouts of PA lasting<1 min played a significant role in controlling abdominal fat distribution.

Minute-by-minute stepping rate of daily physical activity in normal and overweight/obese adults

SUMMARY The relationship between minute-by-minute stepping rate under free-living and obesity remains unclear. The purpose of the present investigation was to compare the levels of physical activity (PA) based on the minute-by-minute stepping rate under free-living conditions between normal weight (NW) and overweight and obese (OV) individuals. A total 40 volunteers participated in the present investigation. These participants were divided into NW or OV according to the body mass index (<25 kg m(-2) or 25 kg m(-2)). All participants wore a pedometer with a uni-axial accelerometer (Lifecorder-EX 4sec, Kenz, Japan) for 7 days continuously. The Lifecorder determined the number of steps and time spent in PA at <100, 100-129, 130 steps min(-1) according to the minute-by-minute stepping rate. The OV group took a significantly fewer number of steps per day in comparison to that in the NW group (p < 0.05). The average daily stepping rate was significantly lower in the OV group in comparison to that in the NW group (p = 0.01). Furthermore, the OV group spent a significantly shorter time in PA at a 100 steps min(-1) of the stepping rate compared with that in the NW group (p < 0.05). These results indicate that obese individuals spent significantly shorter time in PA at 100 steps min(-1) of stepping rate in comparison to the NW individuals.: