A 2012 analysis of this topic, which pooled data from 12 studies published since 1970, provides some interesting observations on the various methods of hand drying. The studies reviewed were all performed in health care settings, but the results have relevance for everyone. The reviewers make the point that how you dry your hands after washing is key to getting rid of germs; in fact, drying the wrong way can undermine the benefits of washing. They noted that it is easier to transmit bacteria from wet hands than dry hands.
Overall, the review found that paper towels work best when compared to jet air dryers, hot air dryers, and cloth roller towels, especially in health care settings where getting rid of germs is particularly important. The advantages of paper towels as outlined in the review are that they dry skin faster, that the friction they create can help get rid of germs missed by washing, and that using them doesn’t present a risk of spreading germs through the air. Another observation: friction during drying can dislodge more microorganisms from the skin surface, possibly even more than through washing with antibacterial soaps.
While jet air and hot air dryers were as efficient for drying as paper towels, more bacteria remained on hands afterwards than when paper towels were used. The reviewers explained that when you rub your hands together under a hot air dryer, they may dry faster, but the rubbing could send bacteria off into the air or cause other germs to migrate from hair follicles to the skin surface. They also make the point that the forced hot air from these dryers can irritate skin leaving hands dry, rough and red. This is a bigger disadvantage than you might think, especially in hospitals and other health care settings. Researchers noted that when hands are irritated, health care workers might not wash them as often or as thoroughly as they should.
As you may suspect, cloth roller towels aren’t a good idea for hand hygiene. If you’re unlucky enough to be drying your hands at the end of the roll, you’re likely to pick up germs shed by someone who used the towel earlier.
The analysis also included the results of a 2009 survey of 2,516 adults in the U.S. on hand-drying preferences: a majority, 55 percent, said that they preferred to use paper towels; 25 percent preferred jet air dryers, 16 percent favored hot air dryers, one percent selected cloth roller towels, and three percent were not sure. The review was published in the August 2012 issue of Mayo Clinic Proceedings.
Andrew Weil, M.D.