Sperm counts lower with more TV, less physical activity
Greater exercise is consistent with improved sperm counts, study suggests
Posted: Feb 5, 2013 9:18 AM ET
Last Updated: Feb 5, 2013 2:09 PM ET
Young men who get more exercise and watch less TV have higher sperm counts than those with less healthy habits, a U.S. study suggests.
Men who exercised for 15 or more hours weekly at a "moderate to vigorous" rate had a 73-per cent higher sperm concentration than those who exercised less than five hours per week. Participants were divided into four groups based on their physical activity levels.
The findings come after decades of research in several Western countries into whether declines in sperm quality from men going to fertility clinics indicate widespread drops in the general population of healthy men or are just blips.
"In this population of healthy men, higher moderate-to-vigorous activity and less TV watching were significantly associated with higher total sperm count," said Jorge Chavarro, assistant professor of nutrition and epidemiology at the Harvard School of Public Health.
"Our findings suggest that a more physically active lifestyle may improve semen quality."
To explore the questions involved, Harvard researchers tested sperm samples from 189 men aged 18 to 22 and asked them questions about their physical activity levels, diet and TV viewing.
Chavarro and his co-authors published their results in Tuesday's online issue of the British Journal of Sports Medicine.
None of the participants had sperm counts that would be a cause for alarm, said Warren Foster, a professor in the department of obstetrics and gynecology at McMaster University in Hamilton, who was asked about the results.
"One of the things that we know is that when you engage in moderate to strenuous exercise on a regular basis, serum testosterone increases," Foster said in an interview with CBC News.
"Serum testosterone … is involved in sperm production. As a consequence of that, one would expect to see that the more fit you are that you would potentially see a modest increase in semen quality."
Scientists suspect that regular physical activity may prevent against oxidative stress damage and protect sperm from damage.
Everything in moderation
Higher scrotal temperatures have also been proposed as an explanation, but whether that is a consequence or cause of impaired sperm production is unclear, Chavarro's team said.
The researchers acknowledged that study was limited by the relatively small number of volunteers who provided only a single sperm sample.
Dr. Allan Pacey, senior lecturer in andrology at the University of Sheffield, noted that other research suggests that too much physical activity may harm sperm production.
Chavarro's study did not look at the type and intensity of physical activity.
"My advice would be everything in moderation — and that includes time in the gym as well as watching TV (or perhaps both at the same time!)," Pacey told the Australian Broadcasting Corporation.With files from the Australian Broadcasting Corporation
Top News Headlines
- Toronto mayor fired chief of staff for telling him to 'go away and get help'
- CBC News has learned the details of what precipitated the firing of Mark Towhey as Toronto Mayor Rob Ford's chief of staff — and it was advice from Towhey that Ford needs to 'get help.' more »
- Federal Court won't remove MPs over robocall allegations
- The Federal Court says it won't throw six MPs out of their seats over allegations of widespread vote suppression through automated robocalls in the 2011 federal election. But Judge Richard Mosley did find that fraud occurred in the election. more »
- Alleged Ford crack video seller not responding to calls
- Bridge collapse on Washington interstate drops cars into water
- An Interstate 5 bridge over a river north of Seattle collapsed Thursday evening, dumping vehicles and people into the water, the Washington State Patrol said. more »
Latest Health News Headlines
- 3-D printing of airway tube helps save U.S. baby
- In a medical first, doctors used plastic particles and a 3-D laser printer to create an airway splint to save the life of a baby boy who used to stop breathing nearly every day. more »
- Wait time and primary care reforms stalled
- Shortening wait times for hip and knee replacements, increasing electronic health records and starting a national pharmacare strategy are stalled, according to a new progress report. more »
- Needed: New approaches to defuse 'suicide contagion' among teens
- Mental health experts say we need to find new ways to refer to and discuss suicide, particularly now that a large medical study has confirmed that teens are more susceptible to the idea if they know a schoolmate who died that way. more »
- Fever medicine for infants, children under recall
- Quality concerns with a Chinese producer of acetaminophen have prompted a recall of four fever medications meant for infants and children. more »
- Toronto Mayor Rob Ford fires chief of staff
- 2nd suspect in Tim Bosma murder case to plead not guilty
- 2 more arrests linked to hacking death of British soldier
- Duffy says he wants to give Canadians 'the whole story'
- Vancouver man abandons Porsche on B.C. ferry
- Chained-teen's mom wants man who pleaded guilty 'to suffer'
- Montreal lifts boil-water advisory
- B.C. teen saves pet dog in 'terrifying' cougar attack
- Neil Macdonald: Harper no Obama when it comes to dealing with scandals