Effects of electronic smoking on daytime plasma cortisol levels and the possible ameliorating role of physical activity: a cross-sectional study.

Background: Cortisol is a hormone that regulates metabolism, circadian rhythm, homeostasis, immunity, and normal growth. Physical activity has numerous health benefits, and smoking is associated with several chronic conditions. This study aimed to investigate the combined effects of physical activity and smoking on circulating cortisol levels.

Methods: Diurnal plasma cortisol levels were measured among individuals (age, 35±14 years; n=974) who smoked electronic (e)-cigarettes (n=239), cigarettes (n=230), waterpipes (n=268), and those who did not smoke (n=237) according to physical activity level.

Results: Two-way analysis of covariance showed an effect on cortisol levels of moderate physical activity (p<0.02) and smoking status (p<0.001) without an interaction effect (p>0.3). Group comparisons showed increased (p<0.001) cortisol among e-cigarette users (247.1±7.4 ng/mL) compared to cigarette users (177.8±7.2 ng/mL), waterpipe users (179.8±6.2 ng/mL), and nonsmokers (181.2±7.2 ng/mL) with no statistical differences between other groups (p>0.05). In addition, among the nonsmokers and cigarette smokers, cortisol levels were reduced in individuals with higher participation in moderate physical activity compared to levels in individuals with lower participation (p<0.005).

Conclusion: These results indicate that e-cigarette use is associated with plasma cortisol levels. Physical activity appears to temper cortisol levels in both cigarette smokers and nonsmokers. However, physical activity may not be sufficient to temper plasma cortisol levels associated with e-cigarette use.