Scientists have discovered a healthier way of greeting your friends instead of the customary handshake - bumping fists.
Research has found that bumping fists may be a more hygienic greeting than shaking hands.
Direct contact is needed for most microbes to move, so minimizing the parts of the hand that touch gives bacteria less chance to spread.
Experiments at Aberystwyth University have revealed that habitual handshaking allows movement of germs between people and can help spread contagious illness.
Researchers also looked at grip strength and found that a stronger handshake increased the amount of bacteria shared.
Using rubber gloves and a thick layer of E Coli, scientists exchanged handshakes, high fives and fist-bumps and have shown that transfer of potentially disease-causing bacteria is highest during a handshake.
Dr Dave Whitworth carried out the research, dipping a glove into a bacterial broth before gingerly extending a hand. The pair tested three different greetings and assessed the amount of germs transferred from each contact.
They found that a high dose of bugs were passed on during a handshake.
This was reduced by over half in the high-five, and germ transfer was a whopping 90% lower when bumping fists.
The hygienic nature of the fist bump may be due in part to its speed (typically much quicker than a first-rate handshake) but also because there is a smaller area involved.
The study was inspired by an increase in measures to promote cleanliness in the workplace, such as hand-sanitizers and keyboard disinfectants.
Dr Whitworth said "People rarely think about the health implications of shaking hands. If the general public could be encouraged to fist-bump, there is genuine potential to reduce the spread of infectious diseases."