RESEARCH DIGEST
Mark A. Merrick, PhD, ATC, Column Editor
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OW MANY of your athletes wear nasal dilator strips during competition
or practice? How many of your coaches have provided these strips or
encouraged you to provide them for your athletes? We now see them
everywhere. In fact, I saw some 10-year-old football players in a junior
football league wearing them not long ago. Are these devices really a
benefit to our athletes, or are they just a fad? Over the past few years,
researchers have begun examining this question, and we are now beginning to find some answers.
BreatheRightB nasal strips are by far the most common external nasal
dilators on the market. Bruce Johnson, the inventor of the BreatheRight
strip, originally developed it as a means of relieving his nasal breathing
difficulties caused by a deviated septum (CNS). He applied for a patent
in 1 991, and the strips were licensed to CNS Inc. in 1992. From there,
the marketing blitz took off. BreatheRight strips are now "official locker
room products" of the NFL, the NHL, and Major League Soccer.
BreatheRight even has an "advisory panel" of professional athletes including the NFL's Jerry Rice and the NHL's Peter Bondra (CNS).
Although the marketing and hype have been widely successful, the
real question is, Do these strips provide any benefit to athletes? There
are two predominant theories explaining a potential physiological
mechanism by which nasal dilators might be useful to athletes (O'Kroy).
First, they might decrease airway resistance and therefore increase
minute-ventilation (the volume of air breathed per minute) and the
partial pressure of oxygen (PO,) in the alveoli, leading to greater diffusion of oxygen into the bloodstream and more oxygen being delivered
to working muscles (O'Kroy). Second, the reduction in nasal airway
resistance could make breathing easier and potentially reduce the oxygen cost of breathing. Because breathing muscles woul
_-----.-- g m r e oxygen would be available for the exercising muscles (Harms).
In addition to these physiological mechanisms, the perception of easier
breathing might also be a psychological benefit.
__lly
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2001 Human Kinetics. AT1 6(2). pp. 42-43
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ATHLETIC THERAPY TODAY
Marketing hype and potential mechanisms aside, there
have been a number of good double-blind, placebocontrolled studies involving nasal dilator strips in recent years. From these studies, a number of important
findings have emerged. First, nasal dilator strips do
appear to improve nasal breathing. The nasal valve, a
narrowing in each nostril, is the main restrictor of
airflow through the nose. Researchers have shown that
in many individuals, external nasal dilator strips increase the cross-sectional area of the nasal valve and
thereby the volume of air that passes through the nose
(Griffin, O'Kroy, Seto-Poon). Researchers have also
observed a decrease in nasal airflow resistance in
some individuals wearing nasal dilator strips (O'Kroy,
Seto-Poon).
Altering airflow resistance is an important point,
but ultimately we are more concerned with whether
or not the strips can improve athletic performance.
During rest, we inhale approximately 80 % of the air
we breathe through the nose, but during exercise this
drops to roughly 25-40 % (O'Kroy). The change from
nasal to oral breathing occurs because we need to
dramatically increase our minute-ventilation during
exercise, and nasal breathing cannot supply a large
enough volume of air. Seto-Poon and colleagues demonstrated that using external nasal dilator strips delays the switch from nasal to oral breathing by roughly
15 % . They concluded that these strips do indeed promote nasal breathing but that the delay in switching
to oral breathing was small.
In another set of studies, researchers have shown
a variety of performance improvements with nasal
dilator strips. Griffin and colleagues reported that
during submaximal exercise, the strips decreased
exercise heart rate, perceived exertion, ventilation,
and VO, when compared with a placebo. All of these
would indicate that the participants did not have to
work as hard to maintain their level of exercise. Similarly, Gehring and colleagues showed that external
nasal dilator strips reduced the work of breathing
during maximal exercise in 11 of their 1 9 participants.
Harms and colleagues found that increased work of
breathing can reduce blood flow to active locomotor
muscles. One would certainly suspect that devices that
ATHLETIC THERAPY TODAY
Chinevere TD et al., 1999,J Sport Sci. 17:443-447.
CNS Inc., www.breatheright.com (October 30, 2000).
Gehring J M et al., 2000, JAppl Physiol. 89:1114-1122.
Griffin JW et al., 1997, Laryngoscope. 107:1235-1238.
Harms CA et al., 1998, J Appl Physiol. 85:609-618.
O'Kroy JA, 2000, Med Sci Sports Exerc. 32: 1491-1495.
Seto-Poon M, 1999, CanJ Appl Physiol. 24538-547.
lessen the work of breathing would allow better blood
flow to other exercising muscles.
W h a t We Don't Know
As you have come to expect in this column, nothing
is entirely straightforward in research-for every article showing an effect, there are other studies showing none. Nasal dilators are no exception. In a recent
article, O'Kroy and colleagues examined the effect of
external nasal dilator strips during exercise. Because
some studies have shown that not all participants have
breathing improvements with nasal dilator strips,
O'Kroy and colleagues used only participants who
reported that they found it easier to breathe while
wearing the strips. During a maximal exercise test,
the nasal dilator group had no improvements in
V02,,x, maximal minute-ventilation, perceived exertion, work rate, or end-tidal (after breath) 0, or CO,
levels. Submaximally, they observed no improvements
in VO,, heart rate, minute-ventilation, end-tidal 0, or
CO,, or perceived exertion. Chinevere and colleagues
also observed no improvement in cardiorespiratory
variables during five maximal treadmill tests while
participants wore nasal dilators.
So whom do you believe? Most researchers have
observed increases in nasal breathing with nasal dilator strips. On the other hand, a slight majority of
articles show no improvements in cardiorespiratory
variables. I t appears that in some cases, for some
people, these strips might have benefits, but clearly
this is not always the case. I
MARCH 2001 1 43