Talking on mobile phone before bedtime can deprive you from a good night's sleep, say researchers.
Scientists from Sweden's Karolinska Institute and Wayne State University in the US say that the radiation from mobile phones can cause insomnia, headaches and confusion.
Their findings are based on a study, wherein the researchers reviewed 35 men and 36 women, aged between 18 and 45.
Some participants were exposed to the same levels of radiation emitted when using a cellphone, while others were given only "sham" exposure.
Those exposed to radiation took longer to enter the first of the deeper stages of sleep and spent less time in the deepest one, interfering with the body's ability to repair damage done during the day.
Children and teenagers were particularly found to be vulnerable to such effects, as they were most likely to use phones late at night and needed sleep the most.
The scientists suggested that people should use a landline if needed to make a call before bed and not to sleep with mobile phones on their bedside table.
Christchurch sleep specialist Dr Mike Hlavac said that it was an interesting study, but he would not be changing his advice to patients without further investigation.
"It's interesting that you can potentially manipulate sleep using mobile-phone signals. It would go with earlier research suggesting radiation might have an impact on sleep," Stuff.co.nz quoted him, as saying.