do it. Some of us do it quite loudly. Others do it not once,
but several times in a row.
are everywhere these days, during this, the height of cold and
flu season. The chorus of achoos in offices, on buses and in
homes often sends bystanders scrambling to get out of the line
of germ-spreading fire.
far is far enough away to avoid getting hit by a
snot-and-fluid projectile? A lot farther than you might ó or
would like to ó think. Weíre talking 20 feet or more.
question of what constitutes an achoo-safe zone has long
intrigued sneeze-ologists, better known as doctors, nurses and
medical researchers working to prevent the spread of
research, however, offers new insights on the science of
sneezing ó revealing what happens when we sneeze and how far
the spray of saliva and mucus can travel.
is a reflex reaction, explained Dr. Scott Davies, a physician
at Hennepin County Medical Center in downtown Minneapolis who
specializes in treating respiratory diseases. It happens when
receptors in the nose detect irritants. It can be an odor,
such as perfume or smoke. It can be pollen in the air or pet
dander ó any type of allergen, really. For some people, cold
air or sunlight can trigger the sneeze reflex. Once the nose
receptors sense the irritant, the brain receives a signal and
the body responds involuntarily.
reflex triggers a violent reaction that involves your neck,
the chest, the abdomen, the diaphragm," Davies said.
"You create this forceful blast of air through your
comes from your lungs, and thereís a deep inhale just before
the sneeze to produce a large gust of air.
of like when youíre blowing out a candle," Davies said.
purpose does sneezing serve?
said Jeanne Pfeiffer, an associate professor at the University
of Minnesota School of Nursing and longtime expert in
infection prevention and control. Think of it as your body
spotting a squatter in the nose that needs to be evicted. The
more someone sneezes, the more likely that pesky freeloader is
still there. Hold the pepper.
helps reset the environment inside the nose, allowing
troublesome particles inhaled through the nose to become
trapped in the mucus lining, according to a recent study
conducted by researchers at the University of Pennsylvania in
long time, people on the front lines of sneeze science thought
that the droplets scattered from a sneeze traveled only a
short distance ó a couple of feet, perhaps. But a
slow-motion video of a sneeze captured recently by
Massachusetts Institute of Technology (MIT) researchers
uncovered a far more troubling truth: Those sneeze particles
can go mighty far.
video shows in gross detail what happens to the liquid mixture
spewed from a personís mouth and nose during a sneeze.
findings, as described by MIT researchers in the New England
Journal of Medicine, show that the droplets spread farther
than previously thought ó aided by a swirling puff cloud.
largest droplets rapidly settle within [about 3 to 6 feet]
away from the person," wrote lead researcher Lydia
Bourouiba, of MITís Fluid Dynamics and Disease Transmission
Laboratory. "The smaller and evaporating droplets are
trapped in the turbulent puff cloud, remain suspended, and,
over the course of seconds to a few minutes, can travel the
dimensions of a room and land up to [19 to 26 feet]
then, is your best defense against contamination from a nearby
canít scamper. Itís over before you can move," Davies
said. "Itís up to the person whoís sneezing to
recommends giving some space ahead of time to avoid getting
say distance is a barrier," she said. "When someone
isnít feeling well but theyíre not staying home, we like
to keep 3 feet of distance."
the day, disease prevention gurus taught us to cover our
mouths with our hands when we felt a sneeze coming on. That
method, while better than an open-mouthed sneeze, is no longer
the preferred method. Thatís because once your hand is wet
and germy, it is easy to transfer those germs to surfaces such
as keyboards, pens and doorknobs ó spreading sickness from
person to person.
and other health professionals now recommend sneezing into a
tissue or into our elbow.
can travel as fast as 100 miles per hour, by some estimates.
And the force of a sneeze? Well, thatís nothing to sneeze
at, either. Davies said while itís extremely rare, some
people have even been injured from sneezing hard.
can break a rib sneezing," he said.