Why sleeping naked is good for you

500 men were monitored over 12 months, noting their choice of underwear. Photo / iStock

A study has revealed why ditching pyjamas at bedtime could improve men's sperm count.

Conducted by the National Institute of Child Health and Development and Stanford University, the study found men who wear boxers during the day then sleep naked have 25 per cent less DNA fragmentation - meaning damage - than men who wear tight boxers day and night.

Over a period of 12 months, 500 men were monitored, noting their choice of underwear and assessing the quality of their sperm.

The study's lead author concluded that the type of underwear worn during the day and to bed is associated with semen quality.

"Better [sperm] quality parameters are observed in men wearing boxers during the day and none in bed."

While the study is creating hype around its links to better fertility, medical professors told HuffPost UK Parents that further research is needed to confirm the findings.

Professor Dr Geeta Nargund, medical director of Create Fertility in the UK said: "Any research that potentially helps men to improve their natural fertility with lifestyle changes should be welcomed. Fertility education and prevention of infertility are important."

He said it is well known that men who are exposed to increased temperature by wearing tight underwear or having hot baths can have reduced sperm quality.

Professor Adam Balen, chair of the British Fertility Society said while the study "supports the notion that keeping the testes cool is better for sperm function... we lack hard evidence that this leads to more pregnancies, which ultimately is all that matters."

- nzherald.co.nz