研究：男人看電視太多或致精子數量減少

最近發表在《英國運動醫學雜誌》的一份研究報告指出，男人精子數量減少或與其看電視的時間太長相關。該研究針對189名18到22歲的健康男性進行，研究發現，每週看電視20小時以上的男性精子數比不看電視的男性少44%。研究人員表示，愛看電視的男性大部分時間都處於久坐不動的狀態，此類狀態或許會影響其精子數量。研究發現，每週做15小時以上適度或劇烈運動的男性比每週運動5小時以下的男性精子數量高。其他有可能影響男性精子數量的因素有：吸菸、身體質量指數以及熱量攝入值等。研究人員指出，該研究只是發現久坐不動生活方式與精子數量之間的關聯，但並不能證明這種生活方式會直接導致精子數量減少；而精子數量減少會否對男性生育能力有影響，也尚需進一步研究來證明。

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.