ResearchPDF Available

The Effect of Nasal Breathing Versus Oral and Oronasal Breathing During Exercise: A Review

Authors:

Abstract and Figures

Article History Keywords Bronchoconstriction VO2max Ventilation Economy Nitric oxide EIB. Historically, exercise physiologists believed that humans produce the greatest physical work by breathing orally. Recently, however, authors from the fields of medicine, health and exercise have described the potential benefits of limiting breathing to the nasal airway during exercise, but actual effects have been infrequently examined in the literature. The purpose of this review was to examine the effects of nasal breathing as compared to oral and oronasal breathing during exercise from the available peer reviewed literature. Studies were identified using six search terms in Google Scholar. All related descriptive studies were included as were experimental studies with the following three criteria: a repeated measures design, randomization of condition order, and valid measurement techniques. The search results yielded a total of 30 published articles as of August, 2019, and both descriptive (n=7) and experimental studies (n=23) were reviewed for the effects of nasal breathing on exercise. The evidence suggests that exclusively nasal breathing is feasible for most people at moderate levels of aerobic exercise without specific adaptation, and that this breathing approach may also be achieved during heavy and maximal levels of aerobic exercise following a sustained period of use. Benefits of nasal breathing include a reduction in exercise induced bronchoconstriction, improved ventilatory efficiency, and lower physiological economy for a given level or work. The use of nasal dilation devices can increase the work intensity achieved during exercise while breathing nasally. Further research on the effects of nasal breathing during exercise is needed. Contribution/Originality: The paper contributes the first logical analysis of the scientific literature addressing the use of nasal versus oral or oronasal breathing during exercise.
Content may be subject to copyright.
1
© 2020 Conscientia Beam. All Rights Reserved.
THE EFFECT OF NASAL BREATHING VERSUS ORAL AND ORONASAL BREATHING
DURING EXERCISE: A REVIEW
George Dallam1+
Bethany Kies2
1Ph.D., Professor, Exercise Science, Physical Education and Recreation, CSU
Pueblo, USA.
2MPH, Ph.D., Assistant Professor, Health Science, CSU Pueblo, USA.
(+ Corresponding author)
ABSTRACT
Article History
Received: 3 October 2019
Revised: 6 November 2019
Accepted: 10 December 2019
Published: 13 January 2020
Keywords
Bronchoconstriction
VO2max
Ventilation
Economy
Nitric oxide
EIB.
Historically, exercise physiologists believed that humans produce the greatest physical
work by breathing orally. Recently, however, authors from the fields of medicine, health
and exercise have described the potential benefits of limiting breathing to the nasal
airway during exercise, but actual effects have been infrequently examined in the
literature. The purpose of this review was to examine the effects of nasal breathing as
compared to oral and oronasal breathing during exercise from the available peer
reviewed literature. Studies were identified using six search terms in Google Scholar.
All related descriptive studies were included as were experimental studies with the
following three criteria: a repeated measures design, randomization of condition order,
and valid measurement techniques. The search results yielded a total of 30 published
articles as of August, 2019, and both descriptive (n=7) and experimental studies (n=23)
were reviewed for the effects of nasal breathing on exercise. The evidence suggests
that exclusively nasal breathing is feasible for most people at moderate levels of aerobic
exercise without specific adaptation, and that this breathing approach may also be
achieved during heavy and maximal levels of aerobic exercise following a sustained
period of use. Benefits of nasal breathing include a reduction in exercise induced
bronchoconstriction, improved ventilatory efficiency, and lower physiological economy
for a given level or work. The use of nasal dilation devices can increase the work
intensity achieved during exercise while breathing nasally. Further research on the
effects of nasal breathing during exercise is needed.
Contribution/Originality: The paper contributes the first logical analysis of the scientific literature addressing
the use of nasal versus oral or oronasal breathing during exercise.
1. INTRODUCTION
The study of energy metabolism via indirect calorimetry in modern exercise physiology has long been
predicated on the assumption that humans will be able to produce the greatest physical work by breathing orally.
The best evidence for proving this assumption is in the Hans Rudolph Valve and mouthpiece Figure 1 a breathing
apparatus historically used by exercise physiologists to measure expired air in research studies. Its original design
allowed for breathing only from the mouth with the nasal passage clipped shut. This approach to the measurement
of indirect calorimetry reflected the basic assumption that oral breathing would allow for greater maximal
ventilation and thereby greater oxygenation during exercise.
Journal of Sports Research
2020 Vol. 7, No. 1, pp. 1-10
ISSN(e): 2410-6534
ISSN(p): 2413-8436
DOI: 10.18488/journal.90.2020.71.1.10
© 2020 Conscientia Beam. All Rights Reserved.
Journal of Sports Research, 2020, 7(1): 1-10
2
© 2020 Conscientia Beam. All Rights Reserved.
However, over the years a small number of research studies have examined the effect of breathing nasally
versus orally and recently there has been a renewed scientific interest in this topic. This interest may have resulted
from a growing number of internet bloggers and/or the book, the Oxygen Advantage (McKeown, 2016) which
strongly advocates for a nasally restricted breathing approach during exercise as a means of reducing various health
problems associated with exercise and improving exercise performance.
2. MATERIALS AND METHODS
In this short review, we have systematically queried and reviewed research which addressed the effect of nasal
versus oral and oronasal breathing in conjunction with exercise. We utilized the database Google Scholar and the
search terms “effect”, “nasal”, “oral”, “oronasal”, “breathing” and “exercise” to identify potential articles for inclusion
in the review. The search was renewed periodically from May through August of 2019. Descriptive studies were
included if the primary focus of the research was related to the use of one or more breathing pathways during
exercise, and if the article was published in a peer reviewed journal. In order to achieve a high quality of
experimental evidence for the review, we only included experimental research papers that met the following three
Journal of Sports Research, 2020, 7(1): 1-10
3
© 2020 Conscientia Beam. All Rights Reserved.
criteria: 1) use of repeated measures design used to allow for direct comparisons across breathing conditions
within subjects, 2) the use of randomization in the order of treatment versus control condition and 3) the application
of valid measurement techniques in the research study. After identifying the articles for review, they were
organized based on descriptive and experimental methodology as well as by the type of airway (s) focused on in the
research, and analyzed for the effects of nasal breathing compared to oral and oronasal.
3. RESULTS
In total, 23 experimental studies and 7 descriptive studies met inclusion criteria and were included in this
review.
After analyzing the articles for the effects of nasal breathing on exercise, other than general contributions of
nasal breathing during exercise, seven categories of topics emerged and are included in the forthcoming discussion.
4. DISCUSSION
4.1. General Contributions of Nasal Breathing during Exercise
During rest and very light cycling exercise of less than 60% of maximal work capacity, or approximately 50
watts of power, the nasal contribution to ventilation is pronounced, with the relative oral contributions increasing
substantially as exercise intensity is increased within this range from rest . However, the relative contribution of
each airway varies widely among individuals, and differs among people of differing races and genders (Bennett et al.,
2003). Children appear to adopt an oronasal breathing pattern more frequently at rest and earlier in progressive
exercise (Becquemin et al., 1999) potentially increasing their exposure to airborne contaminants.
As cycling exercise intensity is further increased a switch to a predominately orally dominated breathing
pattern occurs in most individuals at a mean ventilation of approximately 11 liters/min and power output of 105
watts (Niinimaa et al., 1980). The maximal ventilation seen in subjects achieved prior to switching is approximately
40 liters/min while wearing a face mask and increases slightly to approximately 44 liters/min without the mask
(Saibene et al., 1978). Both studies demonstrate the considerable inter-individual variability that exists in breathing
approach and the individual switching point as well.
Both non-empirical observation (Saibene et al., 1978) and a single descriptive paper derived from observations
of a ten kilometer running race (Niinimaa, 1983) suggest that the vast majority of exercisers breathe oronasally,
with the mouth open continuously, during intensive exercise. This breathing approach can be a non-deliberate
choice and the natural default during heavy exercise in most people.
However, the seminal study comparing the effect of nasal, oral and oronasal breathing during running on VO2
max (Morton et al., 1995) illustrated that any additional nasal contribution during oronasal breathing produces no
effect on maximal oxygen uptake beyond that achievable by oral breathing alone. Another study examining the
effect of a nose clip to create an oral breathing condition versus an oronasal breathing condition also found no effect
of using the clip on high intensity shuttle running performance (Meir et al., 2014) suggesting no benefit of oronasal
breathing versus orally restricted breathing in this condition.
As a result, the available evidence suggests that restricted oral breathing and oronasal breathing are effectively
the same in their ability to increase ventilation and support muscle oxygenation during heavy exercise, with any
nasal contribution being negligible. This observation also offers a hypothesis as to why research looking at the use
of nasal splints during normal oronasal exercise breathing conditions has found no significant effect of doing so
(Chinevere et al., 1999). When breathing orally or oronasally, widening the nasal passage is not likely to be helpful
if the nasal component of total ventilation under high workloads is not significant.
Finally, during exercise nasal resistance to air flow falls, regardless of the airway used for breathing (Saketkhoo
et al., 1979; Forsyth et al., 1983; Olson and Strohl, 1987) suggesting that increased airway resistance by itself is not
a likely to be the sole cause of the switch to an orally dominated breathing pattern during heavy exercise seen in
Journal of Sports Research, 2020, 7(1): 1-10
4
© 2020 Conscientia Beam. All Rights Reserved.
most subjects. Saibene et al. (1978) also found no relationship between flow resistance and the onset of oronasal
breathing and further suggested that the switch is possibly related to the conditions of relative hypoventilation
while breathing nasally (Saibene et al., 1978) while Niinimaa et al. (1980) speculated that the switch was related to
perceptions of increase effort during nasal breathing (Niinimaa et al., 1980). In contrast, Fregosi and Lansing
(Fregosi and Lansing, 1995) found an association between an increase in turbulent airflow in the nasal passage and
an exponential rise in total ventilation, suggesting the onset of oronasal breathing was a possible strategy to reduce
the nasal turbulence resulting in a reduction in total airflow resistance.
4.2. Effects of Nasal versus Oral Breathing on Filtering
One commonly proposed rationale for utilizing a nasal breathing approach during exercise involves the
potential to improve the filtering of airborne particles and/or gases during the increased ventilatory rates seen
during exercise. Unfortunately, only limited work has been done in this area. In 2005, Bennet and Zeman found
that race has a small effect on filtering efficiency with African Americans subjects demonstrating lower filtering
efficiency in comparison to Caucasian subjects for both 1 and 2 um mass particles during light exercise while
breathing nasally, an effect the authors attributed to differences in nasal resistance and nostril s hape. However,
they did not report significant differences in particle filtration efficiency between nasal and oral breathing
conditions. More than a decade earlier, Hynes found that nasal versus oral breathing has no effect on subsequent
lung spirometry or symptomology following exposure to increased ozone (0.4 ppm O3) during 30 minutes of
continuous moderate exercise in both breathing conditions (Hynes et al., 1988). Consequently, the limited available
evidence does not sufficiently support the hypothesis that nasal breathing during exercise will improve the filtering
of airborne particles or gases in comparison to oral breathing.
4.3. Effects of Nasal versus Oral Breathing on Nitric Oxide Production
Another widely hypothesized potential benefit of breathing in a nasally restricted manner during exercise is the
potential for increased release of nitric oxide (NO) from the nasal cavity and its subsequent effects on vasodilation
and red blood cell (RBC) deformability in the cardiovascular system. The existing research (Phillips, 1996; Yasuda
et al., 1997; Bizjak et al., 2019) suggests that exercise increases exhaled NO (which suggests greater NO is produced
by the tissues) and that occlusion of the nasal passage while breathing orally reduces the production overall
(Phillips, 1996). Further, Phillips concluded that the increase in exhaled nitric oxide was more closely related to
increased ventilation than increased blood flow.
In a direct manipulation of nasal versus oral breathing conditions during submaximal cycling exercise, Yasuda
et al. (1997) demonstrated both an increase in exhaled NO as a result of exercise, as well as a greater NO production
overall in the nasal breathing condition (1997), a finding also seen by Bizjak et al. (2019). However, the two
breathing conditions in the Phillips study had no effect on cardiorespiratory responses, although only a limited
number of basic variables were measured.
Finally, Bizjak et al. (2019) recently examined the effect of customary oronasal breathing, oronasal breathing
with an internal nasal stent, and nasal breathing on pre and post NO production and red blood cell deformability
and found decreased red blood cell deformability during the nasal breathing condition, although they also found no
differences in plasma NO concentrations (2019). Greater red blood cell deformability is associated with improved
blood flow, so this finding suggests that nasal breathing may have a negative impact on red blood cell flow.
Consequently, although the available evidence suggests that nasal breathing during exercise may offer the
potential for increased nitric oxide release, the effect on downstream cardiorespiratory factors is still unclear and/or
contradictory to the hypothesis that nasal breathing is beneficial. However, the research addressing this topic is
also still very limited.
Journal of Sports Research, 2020, 7(1): 1-10
5
© 2020 Conscientia Beam. All Rights Reserved.
4.4. Effects of Nasal versus Oral Breathing on Exercise Induced Bronchoconstriction
Three older studies completed prior to 1982 illustrate the potentially beneficial effect of breathing in a nasally
restricted manner versus breathing in an oral/oronasal manner on the occurrence of exercise induced
bronchoconstriction (EIB) in asthmatic subjects with a previously identified EIB/asthma response when breathing
normally (Shturman-Ellstein et al., 1978; Mangla and Menon, 1981; Kirkpatrick et al., 1982). In the Kirkpatrick
study, sulfur dioxide gas was used to initiate and intensify the bronchoconstriction response during exercise, while
the other two studies relied on the natural occurrence of EIB during exercise in asthmatics. In all three studies, the
use of nasally restricted breathing, in comparison to orally restricted or oronasal breathing, reduced and/or
eliminated the subject’s post exercise EIB as measured by a fall in one second forced expiratory volume (FEV1) post
exercise (1982). Consequently, it was concluded by all three researchers that the choice of airway (nasopharynx
versus oropharynx) plays a significant role in the development and resolution of EIB.
4.5. Effect of Nasal versus Oral Breathing on Submaximal Exercise
Most early studies of the nasal versus oral breathing effect on exercise have utilized subject populations who
were not specifically adapted to nasally restricted breathing, a detail which may have greatly influenced how the
outcomes were interpreted (Morton et al., 1995; Garner et al., 2011; LaComb et al., 2017). However, two more recent
studies (Hostetter et al., 2016; Dallam et al., 2018) have examined this effect in subjects who had chosen of their own
accord to adapt to a nasally restricted breathing pattern during exercise, and their results markedly shift the
prevailing interpretation of the previous work. Both types of studies are addressed below.
Several studies directly examining the effect of nasal versus oral breathing on the ability to complete
submaximal endurance exercise (up to 80% of VO2max) in subjects not specifically accustomed to nasally restricted
breathing (Morton et al., 1995; Garner et al., 2011; LaComb et al., 2017) suggest that healthy individuals can
perform such work without any specific need for adaptation to breathing in a nasally restricted manner. This
strongly suggests that a nasal breathing approach is potentially viable during submaximal exercise for a large
proportion of the healthy population without specific need for adaptation.
During steady state submaximal exercise the available research consistently demonstrates that a nasally
restricted breathing approach results in a lower respiration rate (RR), a lower ventilation (VE), a lower ventilatory
equivalent for both oxygen (VE O2) and carbon dioxide (VE CO2), and a lower oxygen uptake (VO2) at a given
steady state work level; a finding which seems to be universal among researchers examining this effect (Morton et
al., 1995; Garner et al., 2011; Hostetter et al., 2016; LaComb et al., 2017; Dallam et al., 2018). In addition, several of
these researchers reported a decreased fraction of oxygen (FEO2) and/or end tidal pulmonary oxygen partial
pressure (PETO2) and an increased fraction of carbon dioxide (FECO2) and/or increased end tidal carbon dioxide
partial pressure (PETCO2) in the expired air of their subjects while breathing nasally at the same tidal volumes and
workloads, suggesting that the slower respiration rate of the nasally restricted breathing approach results in
greater diffusion of both oxygen and carbon dioxide breath to breath (Morton et al., 1995; Hostetter et al., 2016;
LaComb et al., 2017; Dallam et al., 2018).
The lower VO2 seen during nasal breathing has been interpreted speculatively by some researchers as an
indication that such an approach is less effective in oxygenating the body (Garner et al., 2011; LaComb et al., 2017).
However, these studies did not include any measure of anaerobic energy production, which would logically increase
if the lower VO2 resulted from a compromised oxygen uptake, so no real conclusion can be drawn in that regard.
However, the two most recent studies including a comparison of nasal versus oral breathing during
submaximal running and performed in our laboratory (Hostetter et al., 2016; Dallam et al., 2018) examined this
effect in subjects who chose to adopt a nasally restricted breathing pattern in training and racing for significant
periods of time (> 6 months) prior to participating in the research. In addition, these studies examined anaerobic
energy production through the measurement of blood lactate allowing for a clearer interpretation of relative aerobic
Journal of Sports Research, 2020, 7(1): 1-10
6
© 2020 Conscientia Beam. All Rights Reserved.
versus anaerobic energy production. In these studies the decreased VO2 during submaximal work was
accompanied by no increase in blood lactate or rating of perceived exertion, suggesting that oxygen uptake was not
compromised in the nasal breathing condition. Consequently, we offered an alternative interpretation which is that
the lower oxygen uptake seen during submaximal work while breathing nasally represents an improvement in
physiological economy as a consequence of the improved ventilatory efficiency of this breathing approach in those
experienced with the breathing approach (Hostetter et al., 2016; Dallam et al., 2018).
4.6. Effects Nasal versus Oral Breathing on Maximal Exercise
The seminal study performed by Morton et al. in 1995 on the effect of nasal versus oral versus oronasal
breathing on maximal work and VO2max found that normal healthy not specifically adapted to nasal breathing
subjects will experience a significant loss in both VO2max and peak work achieved in a maximal graded exercise
protocol while breathing nasally (Morton et al., 1995) The authors suggested this was primarily due to a large drop
in peak ventilation of approximately 35% in the nasal breathing condition, although they also noted the
significantly better ventilatory efficiency and relatively smaller drops in VO2max (~11%) and time to exhaustion
(~8%)in their subjects at the peak workloads they achieved in the nasal breathing condition. These results
supported the prevailing hypothesis that a nasal breathing approach is insufficient to support heavy exercise due to
the inherent ventilation limitations. However, even Morton et al. questioned this conclusion in their paper as other
published data suggested that ventilation is not a primary limiter to muscle oxygenation (1995).
More recently our research group published work examining the effect of nasal versus oral breathing on
maximal exercise in an initial case study of a triathlete whose chose to adopt a nasally restricted breathing pattern
to self-treat exercise induced bronchoconstriction (Hostetter et al., 2016) and a group of recreational runners who
chose to do the same (Dallam et al., 2018). In these actively nasal breathing runners, we found that they were able
to achieve the same peak work output and VO2max, without an increase in lactate, while breathing nasally as they
were able to do while breathing orally. As in the Morton et al study, their peak ventilation was lower while
breathing nasally (~25%) although not to the same degree as Morton’s non-adapted subjects (~35%). We
hypothesized that the peak work reduction seen in Morton subject’s may have been due to air hunger limitations,
the sensitivity to the increased end tidal CO2 necessitated by the lower respiratory frequency seen during nasal
breathing. By contrast our subjects may have down regulated their sensitivity to end tidal CO2 allowing them to
continue to further increase work and ventilation while breathing nasally to the level necessary to achieve the same
VO2max and peak work achieved while breathing orally (Dallam et al., 2018).
Further, all three studies suggest the mechanism by which a reduced peak ventilation can be overcome to allow
for adequate oxygenation during high level work is the increased diffusion of oxygen with each breathe (Morton et
al., 1995; Hostetter et al., 2016; Dallam et al., 2018). This mechanism was illustrated by a decreased end tidal
fraction of oxygen and pulmonary end tidal oxygen pressure at the same tidal volume while in the nasal breathing
condition at a given work level in all three studies. This phenomenon may result directly from the reduced
respiration rate seen when breathing nasally in comparison to breathing orally during exercise, which logically
allows more time for diffusion.
However, the slower respiratory rate in nasal breathing also results in a higher end tidal carbon dioxide (CO2)
fraction and pulmonary end tidal CO2 pressure as well, suggesting a greater diffusion of CO2 from the blood to the
lung. We speculated that because increased end tidal CO2 has been previously associated with increased air hunger
at rest and will down regulate with increased exposure at rest, that this may occur during exercise as well
(Hostetter et al., 2016; Dallam et al., 2018) suggesting a possible mechanism by which nasal breathing is initially
limiting to maximal exercise, as well as a means by which one might adapt to this breathing approach to remove
such limitations. In addition, this proposed mechanism parallels the suggestions of both Saibene et al. (1978) and
Journal of Sports Research, 2020, 7(1): 1-10
7
© 2020 Conscientia Beam. All Rights Reserved.
Niinimaa (1983) that the nasal to oronasal switching point may be related to hypoventilation and an increased
perception of effort respectively.
4.7. Effects of Nasal versus Oral Breathing on Supramaximal Anaerobic Work
A single study has been published looking at the effect of nasal versus oral breathing on the ability to perform
workloads beyond those achievable at VO2max, whereby anaerobic metabolic processes dominate energy
production (Recinto et al., 2017). This study found no significant effect of breathing route on 30 second Wingate
cycling protocol performance, a finding that logically reflects the idea that such very short maximal work is limited
primarily by anaerobic energy mechanisms, whereby the route of ventilation may be inconsequential. They further
demonstrated a smaller increase in ventilation while breathing nasally, as has been seen in all other studies
examining nasal versus oral breathing during exercise (Recinto et al., 2017). This finding suggests that a nasally
restricted breathing approach may be possible for most healthy people when using short anaerobically dominated
work such as weight training and sprinting without prior adaptation.
4.8. Effects of Dilator Devices on Nasal Breathing
In spite of the fact that nasal splints have been shown to have little or no effect on traditional oronasal
breathing and performance (Chinevere et al., 1999) several studies suggest that such devices are beneficial under the
conditions of nasally restricted breathing during exercise (Petruson and Bjurö, 1990; Seto-Poon et al., 1999;
Gehring et al., 2000; Tong et al., 2001). These studies identified a small increase in nasal ventilation using the
dilator strip which results from a reduced resistance to nasal flow (Gehring et al., 2000) and allows for both an
increased tolerance to a given level of submaximal work (Tong et al., 2001) and a later switching point to oronasal
breathing (Seto-Poon et al., 1999).
Additionally, Petruson and Bjurö (1990) demonstrated a large increase (29%) in nasal flow using an internal
nasal dilator (Nasovent™) which allowed non-adapted subjects to reach peak exercise workloads similar to those
they could reach breathing oronasally (Petruson and Bjurö, 1990). The reported increase in peak ventilation in their
study is similar to the reductions in peak ventilation found in the nasal only breathing condition in Morton et al.
study looking at maximal work responses, so their finding suggests that initial limitations in exercise tolerance in a
nasally restricted breathing condition may be largely overcome simply by using such a breathing device. They
further identified a smaller increase in systolic pressure in the subjects when breathing nasally with the internal
nasal dilating device.
Speculatively, the increase in nasal flow when using a dilating device may serve to lower end tidal CO2 and air
hunger at a given work level, allowing for increased work tolerance in the nasally restricted breathing condition.
In addition our studies using subjects previously adapted to nasally restricted breathing (Hostetter et al., 2016;
Dallam et al., 2018) utilized nasal dilator strips during testing to offset the potentially inhibiting effect to the nasal
flares created by a full face mask design, an outcome we experienced in pilot testing, and which severely
compromised peak work capacity in the nasally restricted breathing condition. This effect may be further evidenced
by the Saibene study which found a significantly greater ventilation at the nasal to oronasal switching point in their
subjects when not wearing a full face mask (1978).
4.9. Methodological Limitations
The primary methodological limitation of this review is that a relatively small volume of controlled
experiments have been conducted to date examining the direct effect of oral and oronasal breathing versus nasal
breathing, consequently, many potential effects remain unexamined. However, the recent increase in interest in this
topic may reflect new studies which address the primary limitation of a nasally restricted breathing approach, which
Journal of Sports Research, 2020, 7(1): 1-10
8
© 2020 Conscientia Beam. All Rights Reserved.
is the effect of slower rates of respiration on peak ventilation and breath to breath CO2 exchange and the resulting
occurrence of air hunger and reduction in peak work capacity.
5. CONCLUSIONS AND RECOMMENDATIONS
In summary, while limited research exists examining the effect of nasal breathing during exercise in
comparison to the more conventional oral and/or oronasal breathing approach, some evidence supports the idea
that a nasally restricted breathing approach may be a feasible way to improve respiratory health during exercise,
particularly in asthmatics with existing EIB. A significant body of evidence also unanimously illustrates the concept
that nasal breathing results in better ventilatory efficiency than oral/oronasal breathing during exercise, which may
also result in an improvement in physiological economy. Further, the available evidence suggests that most
healthy individuals should be able to complete both moderate intensity aerobic exercise and/or short term
anaerobic exercise in the nasal breathing condition without need to for specific adaptation. However, heavy and/or
maximal aerobic exercise may require specific long term adaptation (> 6 months) to a nasal breathing approach to
overcome initial limitations to peak VO2 and work capacity. In addition, the use of a device designed to further
open the nasal flares will increase ventilation in the nasal breathing condition and increase the peak workload which
can be achieved prior to adaptation. Finally, new evidence is suggestive of the concept that the switch to
oral/oronasal breathing during progressively increasing intensity exercise, as the well as the limits to the intensity
of work that may be achieved while breathing nasally, may be a consequence of increased air hunger resulting from
an increased PET CO2, a limitation which can be overcome through adaptation resulting from the increased use of
nasal breathing in practice.
Accordingly, our primary recommendation is that researchers continue to examine the viability and effects of
using a nasal breathing approach during exercise. Specifically, we suggest the need for studies examining the
adaptive process required to adapt to breathing in a nasally restricted manner during heavy exercise, as well as
studies examining the effects nasal breathing during exercise has on performance outcomes, autonomic regulation,
nitric oxide production, cardiac blood flow and the filtering of airborne particles and gases.
Funding: This study received no specific financial support.
Competing Interests: The authors declare that they have no competing interests.
Acknowledgement: Both authors contributed equally to the conception and design of the
study.
REFERENCES
Becquemin, M.M., J.F. Bertholon, A. Bouchikhi, J.L. Malarbet and M. Roy, 1999. Oronasal ventilation partitioning in adults and
children: Effect on aerosol deposition in airways. Radiation Protection Dosimetry, 81(3): 221-228.Available at:
https://doi.org/10.1093/oxfordjournals.rpd.a032588.
Bennett, W.D., K.L. Zeman and A.M. Jarabek, 2003. Nasal contribution to breathing with exercise: Effect of race and gender.
Journal of Applied Physiology, 95(2): 497-503.Available at: https://doi.org/10.1152/japplphysiol.00718.2002.
Bizjak, D.A., P. Schams, W. Bloch, M. Grau and J. Latsch, 2019. The intranasal AlaxoLito plus nasal stent: Improvement of NO-
induced microrheology and oxygen uptake during exercise? Respiratory Physiology & Neurobiology, 269:
103260.Available at: 10.1016/j.resp.2019.103260.
Chinevere, T.D., E.W. Faria and I.E. Faria, 1999. Nasal splinting effects on breathing patterns and cardiorespiratory responses.
Journal of Sports Sciences, 17(6): 443-447.Available at: 10.1080/026404199365759.
Dallam, G.M., S.R. McClaran, D.G. Cox and C.P. Foust, 2018. Effect of nasal versus oral breathing on Vo2max and
physiological economy in recreational runners following an extended period spent using nasally restricted breathing.
International Journal of Kinesiology and Sports Science, 6(2): 22-29.Available at:
https://dx.doi.org/10.7575/aiac.ijkss.v.6n.2p.22.
Journal of Sports Research, 2020, 7(1): 1-10
9
© 2020 Conscientia Beam. All Rights Reserved.
Forsyth, R.D., P.P. Cole and R.J. Shephard, 1983. Exercise and nasal patency. Journal of Applied Physiology, 55(3): 860-
865.Available at: https://doi.org/10.1152/jappl.1983.55.3.860.
Fregosi, R.F. and R.W. Lansing, 1995. Neural drive to nasal dilator muscles: Influence of exercise intensity and oronasal flow
partitioning. Journal of Applied Physiology, 79(4): 1330-1337.Available at:
https://doi.org/10.1152/jappl.1995.79.4.1330.
Garner, D.P., W.D. Dudgeon, T.P. Scheett and E.J. McDivitt, 2011. The effects of mouthpiece use on gas exchange parameters
during steady-state exercise in college-aged men and women. The Journal of the American Dental Association, 142(9):
1041-1047.Available at: https://doi.org/10.14219/jada.archive.2011.0325.
Gehring, J.M., S.R. Garlick, J.R. Wheatley and T.C. Amis, 2000. Nasal resistance and flow resistive work of nasal breathing
during exercise: Effects of a nasal dilator strip. Journal of Applied Physiology, 89(3): 1114 -1122.Available at:
https://doi.org/10.1152/jappl.2000.89.3.1114.
Hostetter, K., S. McClaran, D.G. Cox and G. Dallam, 2016. Triathlete adapts to breathing restricted to the nasal passage
without loss in VO2max or VVo2max. Journal of Sport and Human Performance, 4(1): 1-7.Available at:
http://dx.doi.org/10.7575/aiac.ijkss.v.6n.2p.22.
Hynes, B., F. Silverman, P. Cole and P. Corey, 1988. Effects of ozone exposure: A comparison between oral and nasal breathing.
Archives of Environmental Health: An International Journal, 43(5): 357-360.Available at:
https://doi.org/10.1080/00039896.1988.9934949.
Kirkpatrick, M.B., D. Sheppard, J.A. Nadel and H.A. Boushey, 1982. Effect of the oronasal breathing route on sulfur dioxide-
induced bronchoconstriction in exercising asthmatic subjects. American Review of Respiratory Disease, 125(6): 627-
631.Available at: 10.1164/arrd.1982.125.6.627.
LaComb, C.O., R.D. Tandy, S.P. Lee, J.C. Young and J.W. Navalta, 2017. Oral versus nasal breathing during moderate to high
intensity submaximal aerobic exercise. International Journal of Kinesiology and Sports Science, 5(1): 8-16.Available at:
http://dx.doi.org/10.7575//aiac.ijkss.v.5n.1p.8.
Mangla, P. and M. Menon, 1981. Effect of nasal and oral breathing on exercise-induced asthma. Clinical & Experimental
Allergy, 11(5): 433-439.Available at: https://doi.org/10.1111/j.1365-2222.1981.tb01616.x.
McKeown, P., 2016. The oxygen advantage: The simple, scientifically proven breathing technique that will revolutionize your
health and fitness. New York: Harper Collins.
Meir, R., G.-G. Zhao, S. Zhou, R. Beavers and A. Davie, 2014. The acute effect of mouth only breathing on time to completion,
heart rate, rate of perceived exertion, blood lactate, and ventilatory measures during a high-intensity shuttle run
sequence. The Journal of Strength & Conditioning Research, 28(4): 950-957.Available at:
https://doi.org/10.1519/jsc.0000000000000246.
Morton, A., K. King, S. Papalia, C. Goodman, K. Turley and J. Wilmore, 1995. Comparison of maximal oxygen consumption
with oral and nasal breathing. Australian Journal of Science and Medicine in Sport, 27(3): 51-55.
Niinimaa, V., 1983. Oronasal airway choice during running. Respiration Physiology, 53(1): 29-133.Available at:
https://doi.org/10.1016/0034-5687(83)90021-X.
Niinimaa, V., P. Cole, S. Mintz and R.J. Shephard, 1980. The switching point from nasal to oronasal breathing. Respir Physiol,
42(1): 61-71.Available at: https://doi.org/10.1016/0034-5687(80)90104-8.
Olson, L.G. and K.P. Strohl, 1987. The response of the nasal airway to exercise. American Review of Respiratory Disease,
135(2): 356-359.
Petruson, B. and T. Bjurö, 1990. The importance of nose-breathing for the systolic blood pressure rise during exercise. Acta
Oto-laryngologica, 109(5-6): 461-466.Available at: https://doi.org/10.3109/00016489009125170.
Phillips, C., 1996. Giraud GD, and Holden WE. Exhaled nitric oxide during exercise: Site of release and modulation by
ventilation and blood flow. Journal of Applied Physiology, 80(6): 1865-1871.Available at:
https://doi.org/10.1152/jappl.1996.80.6.1865.
Journal of Sports Research, 2020, 7(1): 1-10
10
© 2020 Conscientia Beam. All Rights Reserved.
Recinto, C., T. Efthemeou, P.T. Boffelli and J.W. Navalta, 2017. Effects of nasal or oral breathing on anaerobic power output and
metabolic responses. International Journal of Exercise Science, 10(4): 506-514.
Saibene, F., P. Mognoni, C.L. Lafortuna and R. Mostardi, 1978. Oronasal breathing during exercise. Pflügers Archive, 378(1):
65-69.Available at: https://doi.org/10.1007/bf00581959.
Saketkhoo, K., I. Kaplan and M.A. Sackner, 1979. Effect of exercise on nasal mucous velocity and nasal airflow resistance in
normal subjects. Journal of Applied Physiology, 46(2): 369-371.Available at:
https://doi.org/10.1152/jappl.1979.46.2.369.
Seto-Poon, M., T.C. Amis, J. P. Kirkness and J.R. Wheatley, 1999. Nasal dilator strips delay the onset of oral route breathing
during exercise. Canadian Journal of Applied Physiology, 24(6): 538-547.Available at: https://doi.org/10.1139/h99-
035.
Shturman-Ellstein, R., R. Zeballos, J. Buckley and J. Souhrada, 1978. The beneficial effect of nasal breathing on exercise-induced
bronchoconstriction. American Review of Respiratory Disease, 118(1): 65-73.Available at: 10.1164/arrd.1978.118.1.65.
Tong, T., F. Fu and B. Chow, 2001. Nostril dilatation increases capacity to sustain moderate exercise under nasal breathing
condition. Journal of Sports Medicine and Physical Fitness, 41(4): 470-478.
Yasuda, Y., T. Itoh, M. Miyamura and H. NISHINO, 1997. Comparison of exhaled nitric oxide and cardiorespiratory indices
between nasal and oral breathing during submaximal exercise in humans. The Japanese Journal of Physiology, 47(5):
465-470.Available at: https://doi.org/10.2170/jjphysiol.47.465.
Views and opinions expressed in this article are the views and opinions of the author(s), Journal of Sports Research shall not be responsible or answerable for
any loss, damage or liability etc. caused in relation to/arising out of the use of the content.
... The factor that primarily contributes to airway resistance is its diameter (Dallam & Kies, 2020). The nasal valve is a structure located approximately one centimetre from the nasal orifice and is responsible for about 50 to 60% of total airway resistance in the respiratory tract as it is the narrowest passage of the nose, and tends to collapse during inspiration, increasing resistance to the passage of air (Dinardi et al., 2014;Ellegard, 2006). ...
... Studies investigating the effects of NDs use on athletes' performance involve different subjects, types of exercise, and outcomes. Thus, the results are conflicting (Dallam & Kies, 2020;Dinardi et al., 2014;Ellegard, 2006;Ferreira et al., 2020;Gelardi et al., 2019). Given the specificity of each sport in terms of ventilatory, physiological, and metabolic aspects, it is necessary to systematize data on the effectiveness of the ND for each modality. ...
Article
Nasal dilators were created to expand the nasal valve area. The aim of this systematic review was to verify physiological parameters associated to running performance with the use of nasal dilators. This study was registered in PROSPERO (CRD42021225795). According to the PICOS framework studies were included: Population: healthy subjects; Intervention: nasal dilators; Comparison: control group, placebo, minimal intervention, health education or other intervention; Outcomes: cardiorespiratory parameters and subjective perceptions; Study: randomized controlled trials, repeated measures or within-subjects design. The databases searched were MEDLINE, EMBASE, CENTRAL The Cochrane Library, CINAHL, SPORTDiscus, Web of Science, PEDro and Scopus. The descriptors "Running", "Nasal Dilator", "Randomized Controlled Trial", and synonyms were used. The risk of bias was assessed using the PEDro scale. Random effects Der Simonian and Laird model were used. The assessment of the certainty of the evidence was carried out using the GRADE approach. Eleven articles were included. There was a difference in favour of the nasal dilator when compared to placebo for maximal oxygen uptake and rating of perceived exertion. The certainty of the evidence was very low. Future studies will probably have an impact on estimation of the effect.
... Breathing patterns (BrP) differ according to breathing frequency, breathing depth, inhalation/exhalation time relationship, and maneuvers applied during expiration (Dallam & Kies, 2020). Expiratory maneuvers are particularly important since changing the resistance of the airways upon expiration can help maintain a positive pressure until the end of exhalation, thus keeping the alveoli and airways open (Francis & Brasher, 1991) longer during the exhalation period. ...
Article
Full-text available
Purpose: Positive expiratory pressure (PEP) exhalation during exercise is reported to improve body adaptation to exercise and enhance the exercise tolerance in patients with chronic obstructive pulmonary disease. Wearing mouthguards results in lower oxygen consumption and increased performance by increasing PEP in athletes. Airway resistance during expiration can be manipulated by phonation. Thus, the aim of our study was to examine the effects of phonated breathing on cardiopulmonary adaptation to moderate exercise and subsequent recovery. Methods: 26 young healthy participants conducted the same moderate steady cycling protocol using three different breathing patterns: spontaneous breathing (BrP1), phonated breathing pronouncing the sound “h” (BrP2) and phonated breathing pronouncing the sound “sh” (BrP3). Heart rate, oxygen consumption, CO2 production, respiratory rate, tidal volume, respiratory exchange ratio and ventilatory equivalents were measured (Cosmed, Italy) before, during and 20 minutes after cycling. Data were analyzed using SPSS, with significance level p<0.05. Results: The analysis revealed no significant differences related to the breathing economy; respiratory rate was increased, and tidal volume decreased with spontaneous breathing compared to both phonated breathing patterns during exercise; no effect of BrPs on cardiopulmonary parameters was found in recovery. Conclusion: Our results do not confirm the assumption that PEP breathing improves exercise economy probably because of the low exercise intensity applied. Further studies should be conducted at higher exercise loads or in patients with pulmonary dysfunction.
... Humans usually switch to mouth breathing at V E = 40 L/min, leading to the assumption that mouth breathing is a requirement during exercise (Saibene et al., 1978). Despite this assumption, studies have demonstrated that humans have surprising flexibility in airway choice during exercise (Morton et al., 1995;Dallam and Kies, 2020). Thomas et al. (2009) reported that subjects were able to maintain nasal breathing up to 85% VO 2max during exercise when instructed with a familiarization but no other accommodation. ...
Article
Full-text available
Running is among the most popular sporting hobbies and often chosen specifically for intrinsic psychological benefits. However, up to 40% of runners may experience exercise-induced dyspnoea as a result of cascading physiological phenomena, possibly causing negative psychological states or barriers to participation. Breathing techniques such as slow, deep breathing have proven benefits at rest, but it is unclear if they can be used during exercise to address respiratory limitations or improve performance. While direct experimental evidence is limited, diverse findings from exercise physiology and sports science combined with anecdotal knowledge from Yoga, meditation, and breathwork suggest that many aspects of breathing could be improved via purposeful strategies. Hence, we sought to synthesize these disparate sources to create a new theoretical framework called “Breath Tools” proposing breathing strategies for use during running to improve tolerance, performance, and lower barriers to long-term enjoyment.
Article
The increase in core temperature during exercise in a hot environment causes hyperventilation (hyperthermia-induced hyperventilation), which decreases the partial pressure of arterial blood carbon dioxide. However, the effects on the body of wearing a surgical mask during exercise that would cause hyperthermia-induced hyperventilation have not been clarified. Therefore, we investigated such effects. Ten healthy men participated in the study. A 44-minute steady-state load cycling exercise (55% of peak oxygen uptake) was performed under hot environmental conditions (30℃, 70% relative humidity). Two experimental conditions were set: exercising with surgical face mask (MASK) and without a surgical face mask (CON). The experiment was conducted as a randomized crossover design. Body temperatures, respiratory gas exchange, and subjective indices were measured during exercise. In terms of physiological indices, respiratory rate only revealed a main effect and was significantly lower in the MASK than in CON at 44 min of exercise (CON 41.0±19.2 breaths/min, MASK 35.6±11.2 breaths/min p=0.029). No significant differences were observed between conditions in other physiological parameters. As for the subjective indices, dyspnea showed a condition × time interaction (p=0.016), which was significantly higher in the MASK starting at 5 minutes through the end (CON 4.5±3.5 and MASK 8.5±2.1 at the end of exercise p=0.016). No significant differences were observed in other subjective measures. In conclusion, wearing a surgical face mask during moderate-intensity prolonged exercise under hot environmental conditions significantly worsened dyspnea, but no significant differences were observed in other physiological indices or subjective indices.
Article
Prolonged exercise in a hot environment increases the minute ventilation (VE) and respiratory rate (RR) with an increase in core temperature. This hyperthermia-induced hyperventilation decreases the partial pressure of arterial blood carbon dioxide (PaCO2). Conversely, nasal breathing during exercise has been reported to produce low VE and RR values and high PaCO2 values; however, no studies have investigated this in hot environments. Therefore, the purpose of this study was to clarify the effect of nasal breathing on estimated partial pressure of carbon dioxide in arterial blood (PaCO2,estimate) during prolonged exercise in a hot environment. Twelve university endurance athletes participated in the study and performed a 40-minutes steady-state cycling exercise at an intensity of 55% of peak oxygen uptake in a hot environment (room temperature 35℃, relative humidity 40%). Using randomized crossover design, two experiments were performed—nasal breathing condition (NB) and mouth breathing condition (MB). Moreover, physiological indices were measured during the exercise. Rectal temperature increased in both conditions, but there was no significant difference between these conditions. PaCO2,estimate values were significantly higher in NB between 10 minutes and 40 minutes of exercise (p < 0.05) compared to MB, and decreased with time in MB. Compared to MB, the VE was significantly lower in NB between 30 minutes and 40 minutes (p < 0.05), while the RR was significantly lower in NB between 25 minutes and 40 minutes of exercise (p < 0.05). Therefore, nasal breathing during a prolonged moderate-intensity exercise in a hot environment prevented the decrease in PaCO2,estimate due to hyperthermia-induced hyperventilation.
Article
Nasal breathing is of great importance for professional athletes because of the peculiarities of carbon dioxide metabolism in the body. Problems with nasal breathing caused by post-traumatic deformities of the nose can be successfully corrected with the help of rhinoseptoplasty, but the possibility of performing this surgery on patients under 18 years of age is a discussed matter. This study aimed to analyze the results of the effect functional rhinoseptoplasty has on nasal breathing, consider rhinoseptoplasty as the preferred method of treatment for adolescents with post-traumatic deformities of the structures of the nose. The study involved 15 professional athletes aged 15–18 years with post-traumatic deformities of the external nose and troubled nasal breathing. Five of them (33.3%) were female, 10 (66.7%) were male; all underwent open rhinoseptoplasty. The NOSE and SCHNOS questionnaires were used to assess the symptoms of nasal obstruction before and after surgery. Post-surgery, all patients subjectively noted that their nasal breathing improved, which was confirmed by the filled questionnaires. There were no significant complications registered during the follow-up period. Functional rhinoseptoplasty is a viable surgical option for adolescents under 18 years of age.
Article
Full-text available
Introduction: When comparing oral breathing versus nasal breathing, a greater volume of air can be transported through the oral passageway but nasal breathing may also have benefits at submaximal exercise intensities. Purpose: The purpose of this study was to determine breathing efficiency during increasing levels of submaximal aerobic exercise. Methods: Nineteen individuals (males N=9, females N=10) completed a test for maximal oxygen consumption (VO2max) and on separate days 4-min treadmill runs at increasing submaximal intensities (50%, 65%, and 80% of VO2max) under conditions of oral breathing or nasal breathing. Respiratory (respiration rate [RR], pulmonary ventilation [VE]), metabolic (oxygen consumption [VO2], carbon dioxide production [VCO2]) and efficiency measures (ventilatory equivalents for oxygen [Veq×O2-1] and carbon dioxide [Veq×CO2-1] were obtained. Data were analyzed utilizing a 2 (sex) x 2 (condition) x3 (intensity) repeated measures ANOVA with significance accepted at p≤0.05. Results: Significant interactions existed between breathing mode and intensity such that oral breathing resulted in greater RR, VE, VO2, and VCO2 at all three submaximal intensities (p<.05). Veq×O2-1 and Veq×CO2-1 presented findings that nasal breathing was more efficient than oral breathing during the 65% and 80% VO2max intensities (p<0.05). Conclusion: Based on this analysis, oral breathing provides greater respiratory and metabolic volumes during moderate and moderate-to-high submaximal exercise intensities, but may not translate to greater respiratory efficiency. However when all variables are considered together, it is likely that oral breathing represents the more efficient mode, particularly at higher exercise intensities.Keywords: Respiratory physiological processes, Musculoskeletal physiological phenomena, Running
Article
Full-text available
This study investigated the effect of restricting nasal breathing during a series of 20-m shuttle runs. Ten male participants (mean age = 21.7 ± 2.4 years, height = 1.80 ± 0.62 m, mass = 79.2 ± 10.4 kg, sum of 4 skinfolds = 54.5 ± 7.8 mm) were required to either (a) dive on the ground and complete a rolling sequence (condition = GRD) or (b) complete the shuttles while staying on their feet and tagging the line with 1 foot, at the end of each 20-m segment (condition = STD). The shuttle runs were completed with and without a nose clip (no clip = nc; with a clip = clip) under 4 different trial conditions in a randomized order (GRDnc; GRDclip; STDnc; and STDclip), requiring the participants to return on 4 separate occasions separated by 5–7 days. Heart rate was recorded throughout each trial, and the rate of perceived exertion (RPE) was measured at the completion of each shuttle sequence. Pretrial and posttrial lactate and respiratory function measures were also recorded. The general linear model with repeated measures analysis indicated that there was a significant effect for Roll (GRD > STD) (p ≤ 0.05) but not for Clip (p > 0.05) on total time to completion in the trials. There was no significant interaction of the conditions (Roll × Clip) for RPE (p > 0.05). Similarly, there was no significant effect for blood lactate measured 3 minutes post the last shuttle for Roll (p > 0.05) and Clip (p > 0.05). There was a significant main effect on the HR across all 6 time points (i.e., pre, intervals 1–4 and 10 minutes post) (p ≤ 0.05) and for Roll (GRD > STD) (p ≤ 0.05), but not for Clip (p > 0.05). No significant effect of Roll or Clip was found for any of the recorded ventilation measures (p > 0.05). On the basis of these findings, the use of restricted nasal breathing, while performing a high-intensity shuttle sequence as a method of increasing the acute training effect on athletes, is questionable, so strength and conditioning coaches should carefully consider their rationale for using such a training strategy.
Article
Nasal and oral exclusive breathing modes have benefits and drawbacks during submaximal exercise. It is unknown whether these responses would extend to anaerobic work performed at high intensity. Nine individuals (males N = 7, females N = 2) performed a standard Wingate Anaerobic cycle test on a cycle ergometer under nose (N) and mouth (M) only respiratory conditions, performed in a counterbalanced order. A 2 (condition: nose, mouth) × 6 (time: 0–5 sec, 5–10 sec, 10–15 sec, 15–20 sec, 20–25 sec, 25–30 sec) repeated measures ANOVA was used to analyze the data with significance accepted at the p<0.05 level. No differences between breathing mode were observed for any power output or performance measures associated with the Wingate Anaerobic cycle test. Respiratory exchange ratio (RER) was significantly higher in the oral respiration condition from 10 seconds to 25 seconds during the test (p<0.05). On the other hand, heart rate (HR) in the nasal condition was significantly greater during the final two time intervals (p<0.05). Nasal breathing was effective in reducing hyperventilation as RER remained below 1.0. However, elevated HR with nasal breathing indicates increased cardiovascular stress associated with this mode. As breathing mode does not affect power output or performance measures during completion of a high-intensity anaerobic test, preference of the participant should be the determining factor if a choice is available.
Exercise causes a fall in nasal resistance that may be due to sympathetic vasoconstriction in the nasal mucosa. Other factors potentially involved in the exercise effect on nasal resistance are: increased alae nasi muscle activity, passive redistribution of blood to exercising muscle and away from the nasal mucosa, increased nasal air flow, and hyperventilation. In order to determine the importance of these factors, 6 healthy adults had nasal pressure/flow data collected at rest and after bicycle exercise at 100 to 160 W. Erect exercise with nose breathing, erect exercise with mouth breathing, voluntary isocapnic hyperventilation at the minute volumes achieved during exercise, and supine exercise were performed. The alae nasi muscles were voluntarily activated during pressure/flow measurements. The pressure/flow data were displayed on a logarithmic plot; parallel right-ward shifts of this plot indicate falls in nasal resistance mediated by enlargement of the air passage. The position of the plot was defined by the flow rate at which the slope of the logarithmic plot steepens abruptly (V̇tr). Erect exercise with nose breathing caused a fall in nasal resistance in all 6 subjects (mean change in V̇tr, +14.4 L/min). Exercise mouth breathing and supine exercise caused similar falls in nasal resistance in all subjects (mean change of V̇tr, +14.1 and +14.2 L/min, respectively). Voluntary isocapnic hyperventilation had no effect on nasal pressure/flow properties in any subject (mean change in V̇tr, -1.3 L/min). We conclude that the response of the nasal airway to exercise does not depend on activation of the alae nasi muscles, does not depend on the presence of air flow through the nose, is not a response to hyperventilation, and is not due to passive redistribution of blood flow away from the nose.
Article
The authors conducted a study to assess the effects of custom-fitted mouthpieces on gas exchange parameters, including volume of oxygen consumption over time [corrected] (VO(2)), volume of oxygen consumption over time per kilogram of body weight [corrected] (VO(2) /kg) and volume of carbon dioxide production over time [corrected] (VO(2)). Sixteen physically fit college students aged 18 through 21 years performed two 10-minute treadmill runs (6.5 miles per hour, 0 percent grade) for each of three treatment conditions (mouthpiece, no mouthpiece and nose breathing). The authors assigned the conditions randomly for each participant and for each session. They assessed gas exchange parameters by using a metabolic measurement system. The authors used analysis of variance to compare all variables. They set the significance level at α = .05 and used a Tukey post hoc analysis of treatment means to identify differences between groups. The results showed significant improvements (P < .05) in VO(2,) VO(2) /kg and VCO(2) in the mouthpiece condition. The study findings show that use of a custom-fitted mouthpiece resulted in improved specific gas exchange parameters. The authors are pursuing further studies to explain the mechanisms involved in the improved endurance performance exhibited with mouthpiece use. Dental care professionals have an obligation to understand the increasing research evidence in support of mouthpiece use during exercise and athletic activity and to educate their patients.
Article
In order to examine the origin and role of nitric oxide (NO) in exhaled air during exercise, exhaled NO outputs of 8 healthy human subjects were compared using different breathing methods, through the mouth or nose, at two intensities of bicycle exercise. The concentration of NO in the exhaled air and ventilatory gas exchange variables were measured by a chemiluminescence analyzer and a mixing chamber method, respectively. The concentration and total output of NO in the expired air was significantly higher under nasal breathing than under oral breathing for both exercise intensities, whereas no significant difference was observed in cardiorespiratory variables between them. NO output increased significantly when exercise intensity was increased from unloaded (0 W) to 60 W under nasal breathing, but not under oral breathing. A negative correlation among subjects was found between NO output and minute ventilation in both breathing methods only for unloaded exercise. Data indicate that nasal airways have a large contribution, at least 50% of total NO output in the exhaled air during nasal breathing, but this nasal NO may have no further modulation on respiratory function during submaximal exercise by healthy humans.
Article
Nasal mucous velocity and nasal airflow resistance were measured in nine healthy subjects before, during 5 min, and 1 h after submaximal exercise of 20 min with a cycle ergometer set in such a way that heart rate ranged from 125 to 135 beats/min. Nasal mucous velocity rose from a base line of 7.6-12.7 mm/min during exercise and returned to the base-line value 5 and 60 min after exercise. The mean expiratory nasal airflow resistance at a flow of 0.4 l/s decreased from a base line of 1.6-0.6 cmH2O . (l/s)-1 during exercise and returned to the baseline value 5 and 60 min after exercise.
Article
The shift from nasal to oronasal breathing (ONBS) has been observed on 73 subjects with two independent methods. A first group of 63 subjects exercising on a bicycle ergometer at increasing work load (98--196 W) has been observed. On 35 subjects the highest value of ventilation attained with nasal breathing was 40.2 +/- 9.41 . min-1 S.D. Ten subjects breathed through the mouth at all loads, while 5 never opened the mouth. On 13 subjects it was not possible to make reliable measurements. On a second group of 10 subjects utilizing a different techniques which did not need a face mask, the ventilation at which one changes the pattern of breathing was found to be 44.2 +/- 13.51 . min-1 S.D. On the same subjects nasal resistance did not show any correlation with ONBS. It is concluded that ONBS is not solely determined by nasal resistance, though an indirect effect due to hypoventilation and hence to changes in alveolar air composition cannot be ruled out. It is likely that ONBS is also influenced by psychological factors.
Article
The effect of nose breathing on the systolic blood pressure was examined in ten healthy men. Nose breathing was increased above normal by exercise and tested by maximum bicycle ergometry. When the anterior part of the nose was dilated with Nozovent the nasal airflow increased by on average 29%. In this condition, all ten men could cycle at maximum load without mouth breathing and there was a significantly lower increase (13 mmHg) in the systolic blood pressure than when the nasal dilator was not used. The reason for this lower blood pressure increase is unknown. The hypothesis is put forward, however, that facilitated nose breathing decreases the respiratory work, which in turn lowers the systolic blood pressure during exercise.
Article
Mode of inhalation, by nose or by mouth, as a determinant of pulmonary toxicity to acute inhalant exposure has been investigated incompletely. This communication addresses whether there are significant differences in toxic pulmonary responses to acute ozone (O3) exposure between differing modes of inhalation (nasal vs. oral breathing). Changes in the results of pulmonary function tests and symptomatology of healthy young adults were compared following both exclusive nose and exclusive mouth breathing during a 30-min exposure to approximately 0.4 ppm O3 under conditions of moderate continuous exercise. In this single-blind, randomized, crossover study, no significant differences in either the results of pulmonary function tests or in symptomatology were found between the two modes of inhalation.