Effects of sedentary work on physical fitness and serum cholesterol profile in middle-aged male workers

Objectives: To evaluate independent and interactive health effects of physi cal activity at work (PAW) and physical activity at habitual exercise (PAHE ). Methods: A cross-sectional study on 1.117 male workers aged 29 to 46 yea rs with a mean of 37.0 years. Using a self-administered questionnaire, the subjects were classified into 'High'/'Low' (n = 338/779) on PAW. and into ' Yes'/'No' (n = 353/764) on PAHE. As outcome indices. physical fitness expre ssed as maximal oxygen uptake (VO(2)max) was estimated. and serum total cho lesterol (TC), HDL-cholesterol (HDLC) and TC/HDLC ratio were determined. Ag e. body mass index (kg/m(2)), alcohol-drinking and smoking were used as con founding factors. Results: The 'High' PAW group had a significantly higher level of VO(2)max than the 'Low' PAW group (+ 1.0 ml/kg min, 34.4 vs. 33.4 ml/kg min in adjusted means). The 'High' PAW group also had a better profil e of serum cholesterol than the 'Low' PAW group, but it was not significant . The 'Yes' PAHE group had significantly higher levels Of VO(2)max (+ 2.0 m l/kg min, 34.9 vs. 32.9 ml/kg min) and serum HDLC (+ 0.09 mmol/l, 1.48 vs. 1.39 mmol/l). and a significantly lower TC/HDLC ratio (-0.29; 3.90 vs. 4.19 ) than the 'No' PAHE group. Among PAW-PAHE subgroups, the 'High-Yes' group (n = 110), most physically active. had the best profile of VO(2)max and ser um cholesterol, and the 'Low-No' group (n = 536), least physically active, had the worst one. Interactive effects of PAW and PAHE were not found eithe r on VO(2)max or on serum cholesterol profile. All the results were not inf luenced by statistical adjustments for the four confounding factors used he re. Conclusions: Both sedentary work and lack of habitual exercise are very common in Japanese workers. Sedentary work, independently from lack of hab itual exercise, may increase the risk of diseases related to physical inact ivity by affecting physical fitness and serum cholesterol profile.