Exercise and Coronary Heart Disease Risk Markers in Male Smokers and Non-Smokers

Cigarette smoking is a strong and independent risk factor for CHD and is associated with impaired postprandial metabolism. Previous studies suggest that postprandial metabolism and other risk markers for CHD can be improved with acute exercise in healthy non-smokers, but less is known about responses in cigarette smokers. Therefore, the present study will compare the effect of acute exercise on fasting and postprandial risk markers for CHD in healthy male cigarette smokers and non-smokers. A total of 12 healthy male cigarette smokers and 12 healthy male non-smokers matched for age and body mass index will be recruited. Before the main experimental trials, participants will attend the laboratory for a preliminary visit to complete screening questionnaires and to undergo familiarisation, anthropometric measurements (stature, body mass, waist and hip circumference, body fat) and exercise testing to determine maximum oxygen uptake. Participants will complete two, 2-day (08:00-17:00) experimental trials in a randomised cross over design: control and exercise. On day 1, participants will arrive at the laboratory at 08:00 having fasted overnight and a baseline fasting venous blood sample and blood pressure measurement will be taken. A high fat breakfast and lunch meal will be consumed at 08:30 and 12:00, respectively. The control and exercise trials will be identical, except a 60 min bout of treadmill exercise at 60% of maximum oxygen uptake will be performed at 14:30 in the exercise trial. On day 2, participants will arrive at 08:00 having fasted overnight for 10 h and will rest in the laboratory until 17:00. Participants in the smokers group will be asked to stop smoking at 08:00. A high fat breakfast and lunch will be consumed at 09:00 and 13:00, respectively. Venous blood samples from a cannula will be collected in the fasted state and at 0.25, 0.5, 1, 2, 3, 4, 4.25, 4.5, 5, 6, 7 and 8 h after the breakfast meal. Resting arterial blood pressure will be measured in the fasted state and at hourly intervals thereafter.