Demographics of study populations at first entry (n=54)
| Characteristics | N (%) or mean±SD |
| Male | 54 (100) |
| Age (years) | 41.6 (12.4) |
| Range | 21.7–71.2 |
| Body mass index (kg/m2) | 28±4 |
| Race | |
| Caucasian | 50 (92.6) |
| African–American | 2 (3.7) |
| Hispanic | 2 (3.7) |
| Asian | 0 (0) |
| Current smoker | 22 (40.7) |
| Acceleration capacity (ms) | −6.29 (3.62) |
| Deceleration capacity (ms) | 7.62 (3.23) |