The detrimental effects of long-term smoking on cardiovascular health have been well established. Surprisingly, the effects of antecedent cigarette smoking on acute cardiovascular adaptations remain by far under-investigated. This study examined whether acute cardiovascular and neural adaptations during isometric exercise are altered following cigarette smoking.Design and method:
Twelve young, healthy, male habitual smokers performed randomly two experimental protocols: (i) a smoking protocol, during which the participant smoked a single cigarette prior to exercise and (ii) a control protocol, during which the same participant smoked a sham (nicotine-free) cigarette. The testing protocol involved a 5-min baseline, a 5-min smoking, a 10-min post-smoking rest, a 3-min isometric handgrip exercise (at 30% maximum voluntary contraction), and a 3-min recovery. Beat-to-beat blood pressure (BP) was continuously monitored (Finapres). The double product, an index of myocardial myocardial stress, and spontaneous baroreflex sensitivity (BRS) were assessed.Results:
During baseline, systolic/diastolic BP (SBP/DBP), double product, and BRS values did not differ between protocols. However, during the post-smoking rest, both SBP/DBP (140.8 ± 12.1/87.0 ± 6.9 vs. 125.9 ± 7.1/77.3 ± 5.5 mmHg) and double product (12190.7 ± 2365.9 vs. 8391.5 ± 1226.2 mmHg•bpm) were higher vs. the respective period in the control protocol (p < 0.001). During handgrip, the double product increased compared to baseline in both the smoking (17240.0 ± 3893.4 vs. 9100.4 ± 1627.7 mmHg•bpm) and the control (15424.3 ± 3173.4 vs. 8667.6 ± 1236.7 mmHg•bpm) protocol, with a markedly greater increase in smoking vs. control protocol (p < 0.001). BRS decreased in the post-smoking resting period vs. baseline (8.3 ± 4.2 vs. 12.2 ± 5.3 ms/mmHg; p < 0.05), and was lower than the respective period in the control protocol (13.9 ± 4.7 ms/mmHg; p < 0.05). A further decrease in BRS was observed during exercise, resulting in lower BRS during handgrip in the smoking vs. control protocol (4.4 ± 2.6 vs. 7.2 ± 4.6 ms/mmHg; p < 0.05). During recovery, delayed BRS and higher double-product responses were observed in the smoking vs. the control protocol.Conclusions:
Smoking of a single cigarette shortly before exercise, triggers a greater myocardial stress and an exacerbating BRS response during subsequent isometric exercise. Even in healthy young men, perceived as free from the long-term cardiovascular effects of smoking, antecedent smoking induces greater BP responses during exercise and a delayed recovery.