FIGURE 2.

Mean (±1 SEM) plasma nicotine data from 31 participants who smoked tobacco using a waterpipe (triangles) or cigarette (squares) in a laboratory session. While both waterpipe and cigarette smoking were ad libitum, the waterpipe was available for 45 minutes while the cigarette was consumed in approximately 5 minutes. Filled symbols indicate a significant difference from baseline (time 0) and asterisks (*) indicate a significant difference between conditions at that time point (p < .001).¹²