Why some people sleep more than others There are two important aspects of sleep to be considered: quantity and quality, says Dr Ana C Krieger,medical director of the Center for Sleep Medicine at Weill Cornell Medical College. Sleep duration,or quantity,varies widely and may be genetically determined,Dr Krieger said. Some people are considered long sleepers and need to make sure they get enough sleep to function normally during the day. They may be prone to infections if lack of sleep interferes with the immune function. In some instances,Dr Krieger said,people appear to sleep longer,but the sleep is fragmented. In that case,an evaluation by a sleep expert is recommended. With a condition present since childhood,Dr Krieger said,it is likely that your situation is that of a long sleeper - a condition,shared by about 1 to 2 per cent of the population,that is defined by a need for at least 10 hours of sleep at night. If daytime sleepiness occurs despite sleeping more than 9 to 10 hours a night for at least a week,a sleep specialist may be helpful,she said. Dr Krieger suggested that long sleepers try to add one or two hours of sleep each night during the week so that weekend catch-up sleep is not too long. Downside of tech Laptop Wi-Fi said to nuke sperm,but caveats abound The digital age has left mens nether parts in a squeeze,if you believe the latest science on semen,laptops and wireless connections. In a report in medical journal Fertility and Sterility,Argentinian scientists describe how they got semen samples from 29 healthy men,placed a few drops under a laptop connected to the Internet via Wi-Fi and then hit download. Four hours later,the semen was,eh,well-done. A quarter of the sperm were no longer swimming around,for instance,compared to just 14 per cent from semen samples stored at the same temperature away from the computer. And nine per cent of the sperm showed DNA damage,three-fold more than the comparison samples. The culprit? Electromagnetic radiation generated during wireless communication,say Conrado Avendano of Nascentis Medicina Reproductiva in Cordoba and colleagues. Our data suggest that the use of a laptop computer wirelessly connected to the internet and positioned near the male reproductive organs may decrease human sperm quality, they write in their report. At present we do not know whether this effect is induced by all laptop computers connected by Wi-Fi to the internet or what use conditions heighten this effect. A separate test with a laptop that was on,but not wirelessly connected,found negligible EM radiation from the machine alone. Study favours HPV testing for all women over 30 NEW DNA tests looking for the virus responsible for most cases of cervical cancer make sense for all women aged 30 or over,since they can prevent more cases of cancer than smear tests alone,Dutch researchers have said. Results of a five-year study involving 45,000 women provided the strongest evidence yet in favour of using human papillomavirus (HPV) testing,Chris Meijer and colleagues from the VU University Medical Centre in Amsterdam reported in The Lancet Oncology. Most cases of infection with the sexually transmitted virus are cleared naturally by the immune system,but persistent infection with certain HPV strains can lead to cervical cancer. In recent years,tests for these high-risk strains have been developed by companies including Roche and Qiagen. The new tests are known to work well in detecting HPV,but the Dutch study is the first to show they are better than pap smears alone over two screening rounds set five years apart. The researchers,who looked at women aged 29 to 56,said use of HPV tests led to earlier detection of pre-cancerous lesions,allowing for treatment that improved protection against cancer.
