Assessment of the daily physical activity in free-living Japanese men : validation and application study of an accelerometer against the doubly labeled water method

Background - There is a general agreement that measurement of total energy expenditure (TEE) is indispensable to elucidate the changes in energy balance.With the advancement and availability of the doubly labeled water (DLW) method to measure human energy expenditure in free-living condition since 1982, attempts have made to calculate the TEE by adding expenditures from basal metabolic rate (BMR), diet-induced thermogenesis (DIT), and physical activity. However, findings on physical activity-induced energyexpenditure (PAEE) to have a greatest potential for increasing or to be mostlikely responsible for decreasing the TEE are not fully known. Because the DLW method is not recommended when it consists about measuring of physical activity in varying intensities, investigators and practitioners have faild to solve the ongoing problem of shortfalls of accuracy and feasibility in developing methods as golld standards for quantifying physical activity.Purposes - 1) Thus, the present study was first designed to develop a valid and accurate methods such as an accelerometer (AC), regarding other alternative field methods (activity records or AR and a heart rate monitoring or HR) of measuring the TEE whether they are useful over longer periods, inexpensive, and indeed can defferentiate activities of varying intensities against the DLW method. In addition to determine whether the findings from a previous study by monitoring young Japanese men with these three alternative field methods could be extended to older Japanese men. 2) Furthermore, it has been said that physical inactivity may be associated with both a decrease in physical fitness and daily energy expenditure. A decrease in the latter with age greatly increases the chance of being overweight. However, findings about the role of physical activity according to its duration and intensity are still disparate. Therefore, the second key objective of this study was to examine the effect of exercise physical activity (EPA) in addition to the physical fitness, body composition upon TEE in healthy older Japanese men.Materials & Methods - Twenty-four (study-1), then forty (study-2) non-obese Japanese male volunteers gave their informed consent and were conducted over the present study. Their age fell in the range, which considered as not the age group most likely to need activity-related lifestyle interventions (30 to 69 yr-old). The whole experimental period for 15 days, where the measurement of TEE was conducted over the last 14 days. AC was used over a 3-day-period (3dAC), and recordings of AR, HR, and dietary records were performed during these 3 days. AC was also applied extensively over the same period when the DLW method was performed (14dAC). The first day prior to the 14-day-period of TEE measurement was spent for baseline sampling and familiarizing the ssubjects with the different methods monitored in this study. TEE was measured by the DWL method whereas EPA by the AC over the same period of 14 consecutive days. Then the EPA was subdivided, in turn, into threeintensities: low, moderate and high. The accumulated duration (time expressed in minutes) of each of intensities was calculated after removing the effects of non-exercise physical activity (NEPA). BMR was measured for 20 min after 10 h fasting on the morning of the day of DLW dosing. PAEE was calculated by subtracting BMR and DIT (=10% of TEE) from TEE. Body composition and physical fitness (VO_2max) were determined using an underwater weighing method and a treadmill exercise test, respectivery.Results - Study-1) Tee values obtained by AR, HR, 3dAC, and 14dAC ranged from 1750 to 3447 kcal/d, 1691 to 5286 kcal/d, 1716 to 2765 kcal/d, and 1700 to 2855 kcal/d, respectively. While expenditures obtained by HR were similar to those determined by the DLW method-used as a reference method in this study, with a mean difference of 57±603 kcal/d (2%), those obtained by AR, 3dAC, and 14dAC differed substabtially from the DLW method, with mean differences of -335±289 kcal/d (12%), -542±249 kcal/d (-19%), and -566±223 kcal/d (-20%), respectively. AR, HR, 3dAC,and 14dAC were significantly correlated with the DLW method, with r values of 0.76 (P＜0.0001), 0.67 (P＜0.001), and 0.83 (P＜0.0001), respectively. Intra-individual variation indicated by the coefficient of variation (CV) was significantly higher for HR (15±11%, P＜0.001) than for AR (7±4%), 3dAC (7±5%), and 14dAC (8±3%). The samefindings were obtained by performing Bland and Altman plots at the population level. Interestingly, 3dAC and 14dAC were significantly correlated with r=0.97 (P＜0.0001), with a lower mean ddifference of 24 kcal/d. Study-2) BMR (1459±181 kcal/d) declined significantly with age (r=-0.37, P＜0.05), but PAEE (946±320 kcal/d) and TEE (2672±369 kcal/d) did not. Total accumulated duration of NEPA and EPA were 587±124 and 93±29 min, whereas those of low-, moderate-, and high-intensity EPA were 56±15, 31±14, and 6±8 min, resoectively. There was no significant relationship between TEE and low-, moderate- and high-intensity EPA duration, respectively (r=0.16, 0.08, and 0.28,ns), between PAL and low-, moderate- and high-intensity EPA duration, respectively (r=0.21, -0.03, and 0.28, us). Multiple stepwise regression analysis was used to develop an empirical model that relate energy expenditure measured by the DLW (TEE) to age, height, body mass index, FM, FFM, percentage body fat, VO_2max and accumulated duration spent for low-, moderate-, and high-intensity EPA. The results revealed that FFM and high-intensity EPA were indentified as important determinants of TEE and accounted for 51%.Discussion & Conclusion - From the results of study-1, presumably, we found that AC and performed somewhat better than HR. Nevertheless, we suggest that AR would not be recommended for use over a long period in occupational involved individuals. However, same as the previous study, AC appears to be a promising and satisfactory device in estimating TEE at both the group and individual levels. From the results of study-2, intensity and duration of the EPA, evenin short periods appear to changes in PAEE, hence physical activity level, especially in active individuals. The use of such an AC coincide with the DLW method is recommended especially in large-scale studies in future, because this study seems to be relevant, so meaningful for the need to establish what in called “Recommended Physical Activity Allowances” in contribution to the daily risk-related diseases interventions. Also, there is a need to make a compromise about physical activity for physical activity prescription in all categories of age and both gender by a national based study.Thesis (Ph. D.)--University of Tsukuba, (A), no. 3246, 2003.3.25Includes bibliographical referencesASSESSMENT OF THE DAILY PHYSICAL ACTIVITY IN FREE-LIVING JAPANESE MEN : VALIDATION AND APPLICATION STUDY OF AN ACCELEROMETER AGAINST THE DOUBLY LABELED WATER METHOD. ~ ハシナ、ラファマンタナツー ウ