Overturning the Hypothesis that Cigarettes Can Enhance Hematocrit and Improve Aerobic Capacity
J. Mark Van Ness: 0000-0001-5902-8735
Health, Exercise, and Sport Sciences Department
2018 ACSM National Conference
American College of Sports Medicine (ACSM)
May 29 - June 2, 2018
Date of Presentation
Medicine & Science in Sports & Exercise
Some athletes are willing to try any supplement or drug to enhance performance. Recent reports suggest cigarette smoking may improve endurance performance by inducing oxidative stress which would, in turn, stimulate an increase in hemoglobin and thus increase oxygen-carrying capacity. It is important to validate these claims, given the hazardous side effects of cigarette smoking.
PURPOSE: Examine the influence of cigarette smoking on blood hemoglobin levels to determine if smoking stimulates training- like conditions for aerobic enhancement.
METHODS: Hemoglobin and oximetry levels were measured in 594 smokers and 1,626 non-smokers across a wide age-range (ages 15 to 98). Independent variables were age, sex, obesity, smoking status, and presence of diabetes, COPD, or other respiratory diseases. Dependent variables were hemoglobin and oximetry. Independent-samples t tests and chi-square tests were used to detect group differences between smokers and non-smokers. Multiple linear regressions were used to isolate the effect of smoking on hemoglobin and oximetry.
RESULTS: Subjects were 52.5 ± 22.5 years of age, 55.7% were male, 16.5% were obese, average hemoglobin was 13.5 ± 1.9 g/dL, and oximetry was 97.0 ± 2.9%. Independent-samples t tests revealed cigarette smokers’ hemoglobin levels to be 4.6% higher (p<0.001) and oxygen saturation to be 0.3 percentage points higher (p=0.042). Cigarette smokers were also 13.5 years older (p<0.001) and more likely to be male (p<0.001). Age (p<0.001) and sex (p<0.001) were strongly correlated with hemoglobin. When controlling for all significant confounders, multiple linear regression did not demonstrate a significant effect of cigarette smoking on hemoglobin (p=0.317) but it found a reduction of 0.4 percentage points on oximetry (p=0.005).
CONCLUSIONS: Simple t-tests indicated cigarettes might confer an ergogenic advantage via elevations in hemoglobin and oximetry. This, left alone, could suggest inadequate oxygen saturation of the blood (owing to smoking) may simulate training-like conditions. However, the predominant explanatory variables were age and sex. It is not the smoking, but other subject factors of the person who smokes that influences hemoglobin levels. Controlling for confounders, smoking has no effect on hemoglobin and reduced oxygen saturation.
Naylor, G. L.,
Van Ness, J. M.,
Amaral, M. M.,
Saxe, J. M.,
Jacobson, L. E.,
Jensen, C. D.
Overturning the Hypothesis that Cigarettes Can Enhance Hematocrit and Improve Aerobic Capacity.
Paper presented at 2018 ACSM National Conference in Minneapolis, MN.