DOCTORS and nurses take note - rubbing your hands together in a hand dryer leaves them coated with more bacteria than just after you washed them. Even normal skin bacteria may be bad news for sick people.
"When you rub your hands, you bring a lot of bacteria to the surface from the pores of your skin," says Anna Snelling of the University of Bradford, UK. She asked 14 volunteers to dry their hands for 15 seconds using three different types of air dryer, sometimes rubbing their hands together and sometimes not.
When volunteers kept their hands still, the dryers reduced skin bacteria numbers by around 37 per cent compared to just after washing. But the count rose by 18 per cent when volunteers rubbed their hands under one of the machines.
Paper towels proved the most efficient, halving the bacterial count even though volunteers rubbed their hands. That's because the towels actually scrape off the bacteria (Journal of Applied Microbiology, DOI: 10.1111/j.1365-2672.2010.04838.x).
The work was funded by Dyson, the hand-dryer manufacturer based in Malmesbury, UK.
We know germs can be transferred more easily to and from wet hands. Therefore it is essential that hands should be dried after washing. The best way to dry hands remains unclear because few studies about hand drying exist. Where studies have been made the results of these studies conflict.
Most of these studies compare overall concentrations of microbes, not just disease-causing germs, on hands following different hand-drying methods. It has not been shown that removing microbes from hands is linked to better health. Nonetheless, the studies do suggest that using a clean towel or air drying hands are best.