Knocking fists together – known as a fist bump or dap – has been used as a greeting or congratulatory gesture in the sports and rap worlds for many years. But now, researchers from Aberystwyth University in the UK say this kind of greeting is more hygienic than shaking hands and should be used in the public sphere to prevent the spread of germs.
In what The Washington Post called “the fist bump heard ’round the world,” President Barack Obama and his wife Michelle famously gave each other a congratulatory fist bump before he accepted the Democratic nomination in 2008.
Though the president and his wife were probably not trying to avoid each other’s germs, the researchers from this latest study, led by Dr. Dave Whitworth, say shaking hands allows germs to move more freely between people, resulting in the spread of contagious illness. Their results will be published in the August issue of the American Journal of Infection Control.
They were inspired to conduct their study in light of increased measures to promote cleanliness in the workplace – by using hand-sanitizers and keyboard disinfectants, for example.
To assess the nature of how a physical greeting affected bacterial transmission between people, Dr. Whitworth and PhD student Sara Mela wore gloves that they dipped into a thick bacterial broth with the bacteria Escherichia coli. Some types of E. coli can cause diarrhea, urinary tract infections and respiratory illness, among other illnesses.
The bacterium is found in the environment, foods and intestines of both people and animals.
After dipping their gloves into the E. coli broth, the researchers exchanged handshakes, high fives and fist bumps, and then tested the gloves after the greetings to determine the amount of germs that were transferred in each condition.
Results showed that the handshake transmitted the highest amount of the potentially disease-causing bacteria, while the high five reduced this amount by 50%. However, the germ transfer during the fist bump was 90% lower than during a handshake.
Additionally, the team found that the stronger the handshake, the higher the amount of bacteria transferred.
They suggest that a fist bump may be more hygienic than a handshake because it is much faster, and a smaller area of the hand is used. Because direct contact is needed for the majority of microbes to transfer from one person to another, they add that reducing the surface area of the hand used gives the germs a smaller opportunity to spread.
“People rarely think about the health implications of shaking hands,” says Dr. Whitworth. “If the general public could be encouraged to fist bump, there is genuine potential to reduce the spread of infectious diseases.”
Speaking with Medical News Today, he said they have “some tentative plans to look further, taking advantage of the lab-based nature of the model we created but haven’t settled on a topic yet.”
“One interesting question for further research, that our approach can’t address, is to what extent the transmission of flu or other infectious disease does happen through the handshake compared to other routes.”
Recently, Medical News Today wrote about a report released by the Centers for Disease Control and Prevention, which suggested most outbreaks of norovirus from contaminated food happen primarily in restaurants.