Exercising moderately five times a week is critical to improving the health of commercial truck drivers and extending their life span, according to Stanley Lowenthal, chief operating officer of Health Screenings Inc. in Louisville, Ky.Toronto-based researcher Dr. Martin Moore-Ede found that truck drivers face an average life span that is 15 years shorter than the average U.S. male.Contributory factors to this differential include a sedentary lifestyle, irregular schedules, smoking, bad eating habits, stress, fatigue and lack of exercise, said Lowenthal. For the full story, see the May 7 print edition of Transport Topics. .