Pat asks: I am very embarrassed to admit this, but I'm a runner who smokes about 10 to 15 cigarettes a week. I have recent PBs of 3:18 marathon, 1:32 half marathon, and a 19:02 5K. Would my times greatly improve if I stopped smoking?
You are not the only runner who smokes. In fact, several world class marathon runners were smokers prior to racing fast. In 2007, we studied more than 50 men who had participated in every Medtronic Twin Cities Marathon since 1982. Some were pretty fast, some were hanging on. I was surprised by the number of men in that group who smoked previously and even more surprised by the number who still continued to smoke. Most users were "closet smokers" who did not display their indiscretions publicly. Smoking may, in part, explain why a number of runners in the group had high coronary calcium counts on their heart scans (calcifications in the coronary arteries are an early sign of coronary heart disease).
It is hard to say if stopping smoking less than a pack of cigarettes per week would improve your race times, but clearly from my perspective as a doctor, it would improve your health profile. One of the byproducts of burning tobacco is carbon monoxide (CO). Inhaled into your lungs, CO binds to strongly haemoglobin (200 times greater binding power than oxygen), blocking oxygen from that binding site. So, in essence, with each inhalation of cigarette smoke, you take a few red cells out of the oxygen transport system. The cells you are working so hard to maximise with your training are taken out of commission and not carrying oxygen to your working muscles while you are running. Is it enough to reduce performance? Probably, but is it the difference between a 3:18 and a 2:59 marathon? Hard to say; probably not.
When it comes to tobacco use and long-term health, no cigarettes, of course, is best. Your cardiovascular disease risk drops rapidly after stopping smoking. The goal in life is to live well as long as possible and to die fast when the end comes. From my experience over many years with smokers, death is often prolonged due to cancers and obstructive lung disease. If the prospect of improved performance helps you quit smoking, you will be a bit faster and a lot healthier on the roads.