The effect of cigarette smoking on free-living daily physical activity in older claudication patients

The purposes of this study were (1) to determine whether peripheral arterial occlusive disease (PAOD) patients who smoke have a lower free-living daily physical activity than nonsmoking patients and (2) to determine whether the difference in physical activity persisted after controlling for potential confounders such as PAOD severity, age, body composition, and peripheral circulation. Thirty-four smokers (45.5 +/-9.8 years of smoking) and 43 nonsmokers (former smokers who had a smoking history of 35.0 +/- 13.1 years who quit 12.2 +/- 10.5 years prior to investigation) were studied. Patients wore a Caltrac accelerometer and a pedometer on each hip over two consecutive weekdays to assess free-living daily physical activity. Patients were also characterized on age, weight, body mass index (BMI), percent body fat, ankle/brachial index (ABI), calf blood flow, and exercise capacity. The smoking and nonsmoking claudication patients had a similar level of PAOD severity, for no group differences were noted in ABI (P=0.287) and treadmill time to maximal claudication pain (P=0.201). However, the smokers were 35% less physically active than the nonsmokers (264 +/- 123 vs 407 +/- 272 kcal/day; P<0.006), and they took 23% fewer steps (4,116 +/- 2,199 vs 5,329 +/- 2,924 steps/day; P<0.034). After adjustment for group differences in age, weight, BMI, percent body fat, and calf blood flow, the lower activity level of the smokers persisted. The adjusted daily energy expenditure was 27% lower (292 +/- 105 vs 400 +/- 214 kcal/day; P=0.021), and the adjusted amount of daily walking was 29% lower (4,039 +/- 1,760 vs 5,684 +/- 2,235 steps/day; P=0.003). Smoking PAOD patients had a less physically active lifestyle than nonsmoking patients, and the lower activity level of the smokers was independent of PAOD severity, age, body composition, and peripheral circulation.