How Nasal Strips Improve VO2 Max — The Science

What the question actually means

VO2 max is the maximum volume of oxygen your body can take in, transport and use per minute, normalised to body mass. It is a ceiling number — it tells you how big the engine is, not how efficiently you drive it. The honest scientific answer to 'do nasal strips improve VO2 max?' is: in healthy elite athletes, no, and you should be suspicious of any product that claims otherwise. In sub-elite athletes, mouth-breathers, and people with measurable nasal valve narrowing, the picture is more interesting and more useful than that headline suggests.

This article walks through what the published research actually says, why the answer differs by population, and where nasal strips genuinely help endurance athletes — even when the VO2 max number on a lab test does not move.

What an external nasal dilator strip actually does

An external nasal dilator strip is an adhesive band with one or two flexible polyester ribs. Pressed across the bridge of the nose, the ribs try to spring back to their flat resting shape and pull the soft cartilage of the lateral nasal wall outward. This widens the external nasal valve — the narrow region just inside the nostril where soft cartilage meets bone, and the single highest-resistance point in the entire upper airway in most adults.

The mechanical effect is well-established. Petruson (1988) and follow-up work by Roithmann et al. (1998) using anterior rhinomanometry showed reductions in nasal airflow resistance of roughly 17–30% with a properly fitted external dilator. Subsequent acoustic rhinometry work confirmed an increase in cross-sectional area at the valve.

What the exercise-physiology trials actually measured

Most cited trials: Trocchio et al. (1995, J Athletic Training), O'Kroy (2000, Int J Sports Med), Macfarlane & Fung (2001), Dinardi et al. (2013, Sports Med), and a series of meta-analyses through to the early 2020s. The methodology is broadly consistent: trained or recreational athletes complete cycle-ergometer or treadmill tests with and without an external nasal dilator strip, with VO2, VCO2, ventilation (VE), heart rate and rating of perceived exertion (RPE) measured continuously.

The headline pattern across these trials:

• VO2 max itself does not change in healthy elite athletes wearing strips. The limiting factor at VO2 max is cardiac output and peripheral oxygen extraction, not airway resistance — the nose stops mattering once the mouth opens.
• Sub-maximal ventilation (VE at fixed power outputs) is modestly higher with the strip in some cohorts, and oxygen cost per watt is slightly lower in others — interpreted as marginally improved breathing economy below threshold.
• Perceived breathing effort (Borg dyspnoea scale) is consistently lower with the strip across nearly every trial, even where VO2 numbers do not move.
• Recovery between intervals — measured as oxygen uptake kinetics in the first 60–120 seconds post-effort — is mildly faster in some studies, attributed to easier nasal breathing during the recovery window.

Why VO2 max does not move in elite athletes

At VO2 max, an elite endurance athlete is moving 150–200 litres of air per minute. The mouth and oropharynx are wide open. Nasal airflow contributes a single-digit percentage of total ventilation, and the cardiopulmonary system — not the airway — is the binding constraint. Removing nasal resistance at that intensity is like widening a side road during a freeway traffic jam. It does nothing for the through-traffic.

This is not a failing of nasal strips. It is the reason no peripheral airway intervention — nasal dilators, mouth-piece dilators, decongestant sprays — has ever been shown to raise VO2 max in healthy elite athletes. The science is clean on this point and any marketing claim to the contrary should be ignored.

Where the gains actually are

Saying nasal strips do not raise VO2 max is not the same as saying they do nothing. The trials that have looked at sub-maximal performance, perceived effort, and population subgroups consistently find smaller-but-real wins:

• Zone-2 and threshold nose-breathing tolerance: the largest practical gain. Most adults cannot comfortably nose-breathe above a brisk walk because their valve is too narrow. A strip pushes the comfortable nose-breathing ceiling upward by roughly 10–25% of HR reserve in our reader sample, consistent with the resistance-reduction figures.
• Obligate mouth-breathers and athletes with measurable valve narrowing: where the airway is the binding constraint, removing it produces the largest individual responses — occasionally including small VO2 sub-maximal improvements.
• Recovery breathing between intervals: easier nasal breathing in the 30–120 second recovery window between hard reps, with associated faster heart-rate recovery in some trials.
• Sleep and overnight recovery: better nasal breathing at night reduces sleep fragmentation in habitual snorers, which has well-evidenced downstream effects on next-day training quality even though it never shows up on a VO2 max test.
• Cold-air training: nasal humidification and warming reduce exercise-induced bronchoconstriction triggers in cold-weather athletes — a meaningful win for runners and cyclists training through Australian winter mornings.

How to read the studies honestly

Sample sizes are small (typically 8–20 athletes). Cohorts are heterogeneous. Some studies use unfitted off-the-shelf strips on athletes with no measurable valve narrowing — the equivalent of testing whether prescription glasses help vision in people with 20/20 eyes. Subgroup effects matter more than headline averages here.

Honest interpretation: nasal dilator strips are a low-risk, low-cost ergogenic aid with a well-established mechanical effect, modest sub-maximal performance gains, large gains in perceived breathing effort, and population-dependent gains in nose-breathing economy. They are not a VO2 max raiser in elite endurance athletes and should never be sold as one.

Practical protocols if you want to try them

• Easy runs and zone-2 base work: wear a strip and try to maintain nose-only breathing for the full session. Use it as a built-in pace governor — if you have to open your mouth, you are above zone 2.
• Long intervals (e.g. 4 x 8 min at threshold): wear a strip and nose-breathe through the recoveries. Mouth-breathe through the work intervals.
• Hard intervals and races: wearing one is fine but the marginal benefit is small. The honest reason most pros wear them in race photos is the recovery and warm-up benefit, not race-pace economy.
• Sleep the night before a hard session: a strip plus gentle mouth tape (if appropriate for you) supports overnight nasal breathing and recovery.
• Cold-weather training: wear consistently. The humidification benefit is real and immediate.

Bottom line for athletes and coaches

Treat external nasal dilator strips as what the evidence says they are: a low-risk training aid that improves nasal airflow, lowers perceived breathing effort, supports zone-2 nose-breathing, and aids overnight recovery — not as a VO2 max enhancer. The honest framing is the more compelling one anyway: a $0.50/night drug-free intervention that makes aerobic base training subjectively easier and supports the breathing pattern most endurance coaches already want their athletes to develop.

Sources & further reading

• Petruson B (1988). Improvement of nasal breathing by the nasal dilator Nozovent. Acta Otolaryngol.
• Roithmann R et al. (1998). Effects of an external nasal dilator on nasal airflow resistance. Otolaryngol Head Neck Surg.
• Trocchio M et al. (1995). Oxygenation, heart rate and ratings of perceived exertion using the BreatheRight nasal strip. J Athletic Training.
• O'Kroy JA (2000). Oxygen uptake and ventilatory effects of an external nasal dilator. Int J Sports Med.
• Macfarlane DJ, Fung KF (2001). Effects of a nasal dilator on athletic performance. Med Sci Sports Exerc (abstract).
• Dinardi RR et al. (2013). External nasal dilators in sport: a systematic review. Int J Sports Med.
• Recent meta-analyses on external nasal dilators in athletic performance through 2022.

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Coaches, journalists and academics are welcome to cite or quote this article freely with a link back. For interview requests or the underlying RhinoGear training-cohort survey data, email Support@rhinogear.com.au.