Fig. 2.
Comparison of baroreflex control of sympathetic nerve activity (SNA; A) and heart rate (HR; B) in premenopausal women who are never, current, former, and passive smokers, according to menstrual phase. A: baroreflex sensitivity (BRS) (total activity SNA·min−1·mmHg−1) was significantly blunted during both menstrual phases in current smokers compared with never smokers. BRS was not different between menstrual phases in any group. Results were the same when MSNA was measured as bursts/min or bursts/100 heart beats (data not shown). *P < 0.03, never smokers vs. current smokers. B: baroreflex control of HR was not different between menstrual phases in any group. TA, total activity.