Fist bumps more hygienic than shaking hands, says researcher

When it comes to preventing the spread of germs, maybe US President Barack Obama is on to something with his fondness for fist bumps.

The knocking of knuckles spreads only one-twentieth the amount of bacteria that a handshake does, researchers report. That's better than a high five, which still passes along less than half the amount as a handshake.

So fist bumps - popularised by Obama and others - seem to be the wisest greeting, especially during cold and flu season, said researcher David Whitworth of Aberystwyth University in Wales.

The importance of hand hygiene is nothing new in medicine. But the researchers realised that while a lot of research focused on hands getting grimy from touching doorknobs and other surfaces, only a few studies had looked at handshakes.

"And there are alternatives to handshakes. You see them on telly all the time - the fist bump and high five and all that," Whitworth said.

He and a student, Sara Mela, shook hands, fist-bumped and high-fived each other dozens of times for the research. One wore a glove covered in bacteria, while the other had a clean sterilised glove. After each greeting, they measured how much bacteria had been transferred.