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OBJECTIVE:The aim of this study was to investigate the effect of excessive mechanical load caused by obesity on the inspiratory muscle performance in obese men at rest. METHODS:We therefore measure at rest spirometric flows and the noninvasive tension time index of inspiratory muscle (T Tmus ¼ P I /P Imax  T I /T TOT ) in eight obese male subjects (body mass index (BMI)430) and 10 controls. RESULTS: Spirometric flow (FEV 1 % pred, FVC% pred) and maximal inspiratory pressure (P Imax ) were significantly lower in obese subjects compared to controls (Po0.001). The mean T Tmus was significantly higher in obese subjects than in controls (0.13670.003 vs 0.04570.01). The increase in T Tmus was primarily due to an increase in the ratio of mean inspiratory pressure to maximal inspiratory pressure (P I /P Imax ) and the duty cycle (T I /T TOT ). We found a significant negative relationship between P Imax and BMI (r ¼ À0.74, Po0.001), a positive correlation between T Tmus and BMI (r ¼ 0.80, Po0.001) and a negative correlation between T Tmus and forced expiratory volume in 1 s (r ¼ À0.85, Po 0.001). CONCLUSION: Excessive mechanical load caused by obesity imposes a great burden on the inspiratory muscle, which may predispose such subjects to respiratory muscle weakness at rest.

A nosocomial source of HCV infection in hospitalized diabetic patients is suggested by the increased risk of HCV infection associated with the number of hospitalizations. This may account for at least 36% of cases of HCV infection.