Study links caffeine with pregnancy loss. When either men or women drank three or more cups a day of caffeinated drinks before pregnancy — sodas, energy drinks or coffee — the woman was nearly twice as likely to lose that pregnancy early on.

Research has shown that moderate caffeine consumption has no negative influence on sperm count or quality, but reasonable consumption is 300 milligrams, or only about two cups of coffee, says Caitlin Dunne, a fertility doctor at the Pacific Centre for Reproductive Medicine in Vancouver.

In addition to poisoning by caffeine, the consumption of energy drinks has been associated with seizures [5], strokes [6], and gonadotoxic effects [7]. A significant increase in the incidence of male infertility has been described in the literature worldwide, which generates questions about its causes.

Caffeine exposure did not seem to affect adversely the semen quality or the levels of inhibin B or FSH. No association between caffeine and sperm motility or morphology. Men with a high caffeine intake had about 14% higher concentration of testosterone than men with a low caffeine intake.

How can smoking impact my ability to conceive? Women who smoke do not conceive as efficiently as nonsmokers. Infertility rates in both male and female smokers are about twice the rate of infertility found in nonsmokers. The risk for fertility problems increases with the number of cigarettes smoked daily.

Smoking and infertility If you smoke, it is likely to take you longer to get pregnant than a non-smoker. Most couples who have regular, unprotected sex (every 2-3 days) will get pregnant within a year. But for smokers, the chance of getting pregnant are cut by almost half each month.

Smoking exposes men to high levels of cadmium and lead, metals that have been linked to decreased fertility. Lead levels have been found to be significantly higher in infertile smokers when compared to both fertile and infertile non-smokers.

Lung volume Both swimming and long-distance running training result in increased total lung capacity. Results from other studies show that the same benefits can be derived from cigarette smoking as part of a syndrome known as chronic obstructive pulmonary disease (COPD).

A new book called A Smoker’s Guide to Health and Fitness explains how to make the best of a bad habit. (But you should probably still quit.)