Q: Can too much exercise affect fertility?
A: When it comes to exercise, what's hardcore for one person may barely make someone else break a sweat -- so women considering pregnancy should use their own common sense when evaluating their fitness regimens.
Very intense exercise -- we're talking hours a day -- can disrupt your normal menstrual cycle and even make implantation of an embryo more difficult (since irregular periods may make your uterine lining less hospitable). But these kinds of problems rarely affect the average woman -- they're far more common among female professional athletes. As a general rule, if you get your period regularly, then exercise should not affect your ability to get pregnant.
But steady gym-goers should also be aware that significantly raising your body temperature (like from sitting in the steam room after hitting the treadmill or taking an hourlong bikram yoga class) early in pregnancy has been linked to miscarriage and birth defects, so it's a good idea to avoid very intense activities like these while you try to get pregnant, too. Once you're pregnant, talk to your doctor about how much exercise is safe and what types of activities are best.
In terms of your partner, he may want to cut back on exercises like biking, which can position the testicles close to the body and cause them to overheat (this has been known to reduce sperm count in some men). And if he takes anabolic steroids to support his fitness goals, he should stop right away -- medications like these can lower his sperm count, not to mention cause a host of other health problems.