Purpose：The purpose of this study was to investigate the effects of change in daily physical activity during an exercise intervention on health status and physical fitness.Methods：Participants were 22 obese middle-aged men (BMI : 29.1±2.8 kg/m², 54.1±11.4 yr). They performed 90-min exercise sessions on a regular basis 3 days per week for 3 months. Physical activity (total energy expenditure, TEE ; activity energy expenditure, AEE ; and step counts) was measured using an accelerometer. Daily physical activity was defined as that which was performed outside of the exercise class. A 3-day food record was used to estimate energy intake. Results：Body weight decreased (-3.0±2.5 kg, P＜0.05). Vital age (VA), an index of comprehensive health status, and physical fitness age (PFA), an index of comprehensive physical fitness, significantly improved (VA : -8.7±5.5 yr, PFA : -8.5±5.1 yr, P＜0.05). Energy intake remained unchanged during the intervention (＋63.7±546.1 kcal/d). Daily physical activity increased (TEE : ＋83.0±130.1 kcal/d, AEE : ＋76.9±103.3 kcal/d, step counts : ＋1789±2819 steps/d, P＜0.05). Change in daily physical activity was correlated with change in VA (AEE : r＝-0.52, step counts : r＝-0.46, P＜0.05), while change in daily physical activity did not correlate with change in PFA. Conclusion：These results suggest that changes in daily physical activity during an exercise intervention are associated with improved health status.

The purpose of this study was to investigate the accuracy of estimating human body composition changes using bioelectrical impedance (BI) methods during a weight-loss intervention. Subjects were forty-three obese men (age : 49.2±10.5 yr, BMI : 27.8±1.7 kg/m²) who completed a 14-week weight-loss intervention. In all subjects, fat mass (FM) and fat-free mass (FFM) were assessed by dual energy x-ray absorptiometry (DXA) as well as single- and multi-frequency BI methods (SBIM, MBIM) before and after the intervention. Resistance parameters were measured by SBIM and MBIM (SBIM : R₅₀ ; MBIM : R∞, R0, and Rfc). In nine subjects these variables were also measured at weeks 1 and 4. Weight decreased (P<0.05) by -8.0±3.2 kg during the intervention while FFM changes averaged -0.4±1.6 kg (DXA), -2.0±1.5 kg (SBIM), and -1.6±1.7 kg (MBIM). BI methods overestimated FFM before the intervention (before ; DXA : 54.4±4.8 kg, SBIM : 56.5±4.3 kg, MBIM : 55.9±4.5 kg). In nine subjects, FFM measured by SBIM (FFM_SBIM) and MBIM (FFM_MBIM) was similar to FFM measured by DXA(FFM_DXA)(after ; DXA : 54.6±5.4 kg, SBIM : 54.6±3.8 kg, MBIM : 54.6±4.1 kg), although BI methods overestimated the FFM before the intervention (before ; DXA : 54.9±5.1 kg, SBIM : 56.9±3.8 kg, MBIM : 56.3±4.4 kg). The ΔFM_SBIM and ΔFM_MBIM were highly correlated with the ΔFM_DXA(SBIM : r=0.87, MBIM : r=0.88). The ΔFFM_SBIM andΔFFM_MBIM were significantly correlated with the ΔFFM_DXA(SBIM : r=0.54, MBIM : r=0.49). The ΔR₅₀ and ΔRfc were also significantly correlated with the ΔFFM_DXA(R₅₀ : r=-0.63, Rfc : r=-0.48). These results suggest that during a weight-loss intervention, 1) BI methods and DXA provide similar estimates of human body composition change, although they overestimate FFM in obese men, and 2) changes of resistance parameters observed with BI methods may estimate human body composition change more accurately.

A number of studies have shown that sleep disordered breathing (SDB) has a strong relation with obesity. The purpose of this study was to examine the effect of a short-term weight-loss program in obese men with SDB. In our 14-week weight-loss program, forty-one obese men (mean±SD, age ; 49.6±10.8 yr, body mass index ; 27.9±2.5 kg/m²) were assigned to 2 subgroups : diet only (DO ; n=19) and diet plus aerobic exercise (DE ; n=22). 2%, 3%, and 4% oxygen desaturation index (ODI) were measured by pulse oximetry before and after the weight-loss program. Weight and %fat significantly (p<0.05) decreased in the total subject pool consisting of DO plus DE (weight ; -8.4±3.5 kg, %fat ; -7.5±3.5%). 2%, 3%, and 4% ODI significantly decreased by -3.46±5.01 event/hour, -2.37±3.57 event/hour, and -1.99±2.84 event/hour, respectively. Significant correlations were found between 2%, 3%, and 4% ODI at baseline and changes of 2%, 3%, and 4% ODI during the weight-loss program (2% ODI ; r=0.48, 3% ODI ; r=0.51, 4% ODI ; r=0.67). Weight loss and %fat loss did not differ significantly between DO and DE (DO : -7.6±3.2 kg, -6.8±3.2%, DE : -9.2±3.7 kg, -8.1±3.7%). The increase in maximal oxygen uptake was slightly larger for DE (4.7±4.6 ml/kg/min) compared to DO (2.5±3.3 ml/kg/min), but there was no significant interaction. Changes of 2%, 3%, and 4% ODI did not differ significantly between groups. These results suggest that for obese men with SDB, the weight-loss program is an effective method, leading to improvement in SDB, although the combination of aerobic exercise to diet may not produce additional effects to SDB, compared with the diet only.