研究：男人看电视太多或致精子数量减少

最近发表在《英国运动医学杂志》的一份研究报告指出，男人精子数量减少或与其看电视的时间太长相关。该研究针对189名18到22岁的健康男性进行，研究发现，每周看电视20小时以上的男性精子数比不看电视的男性少44%。研究人员表示，爱看电视的男性大部分时间都处于久坐不动的状态，此类状态或许会影响其精子数量。研究发现，每周做15小时以上适度或剧烈运动的男性比每周运动5小时以下的男性精子数量高。其他有可能影响男性精子数量的因素有：吸烟、身体质量指数以及热量摄入值等。研究人员指出，该研究只是发现久坐不动生活方式与精子数量之间的关联，但并不能证明这种生活方式会直接导致精子数量减少；而精子数量减少会否对男性生育能力有影响，也尚需进一步研究来证明。

Guys may now have another reason to get off the couch: Watching TV has been linked to lower sperm counts, a new study suggests.

During the study, which involved 189 healthy 18- to 22-year-olds, men who watched the most TV (20 or more hours a week) had sperm counts that were 44 percent lower than men who did not watch television.

The findings held after the researchers took into account factors that could affect sperm count, such as smoking, body mass index (BMI) and calorie intake.

Men who watch a lot of TV may have a more sedentary lifestyle, which in turn may affect sperm count, the researchers said. Indeed, the men in the study who exercised the most ─ doing 15 or more hours a week of moderate to vigorous physical activity ─ had sperm counts that were higher than those of guys who exercised less than 5 hours a week.

The findings suggest that having a more physically active lifestyle may improve sperm quality, said study researcher Audrey Gaskins, a doctoral student at Harvard School of Public Health. Previous studies have found that being obese and eating a high-fat die are risk factors for lower sperm counts.

However, the new study only found an association, and cannot prove that a sedentary lifestyle lowers sperm count. The researchers also don't know if the lower sperm counts seen in the study would have an effect on the men's fertility.

Given the benefits of a healthy lifestyle, the findings make sense, said Dr. Andrew Kramer, a urologist at the University of Maryland Medical Center, who was not involved in the study. But future studies will be needed to determine if increasing exercise in sedentary men will actually improve their sperm counts, Kramer said.

All the men involved in the study were enrolled at the University of Rochester in N.Y. in 2009 and 2010. They were asked about their levels of physical activity and TV watching during the previous three months. More than half of the men were of normal weight, and 75 percent were nonsmokers.

The study is published today (Feb. 4) in the British Journal of Sports Medicine.