The Bolt Score Test: Measure Your Breathing Volume Capacity

+ 4 ways to improve your score & overall lung health

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One of the primary determinants of how fast and how long you can run without stopping is your lung capacity. Nearly every runner has found breathlessness to be the limiting factor in running faster at one time or another, so improving your lung capacity and aerobic breathing can have significant performance benefits for distance runners.

The BOLT Score Test is a practical way to measure your breathing volume, which can help you chart your aerobic fitness progress from your training.

Performing the BOLT Test is simple, and can be a great way to quantify improvements in your cardiovascular fitness.

A woman out of breath from running on the beach.

What Is the BOLT Score Test?

The BOLT Score Test, which stands for the Body Oxygen Level Test, is a breathing assessment popularized by Patrick McKeown, the creator of Oxygen Advantage1 Home New. (n.d.). Oxygen Advantage. which measures your relative breathing volume during rest as well as breathlessness during exercise.

Patrick McKeown is a big proponent of the power of nose breathing and lighter breathing in healthfulness.

The BOLT Test is not a measurement of how long you can hold your breath per se, but of how long it takes your body to react to a lack of air coming in. 

According to McKeown, the scientific rationale for the BOLT Score Test dates back to 19752 Stanley, N. N., Cunningham, E. L., Altose, M. D., Kelsen, S. G., Levinson, R. S., & Cherniack, N. S. (1975). Evaluation of breath holding in hypercapnia as a simple clinical test of respiratory chemosensitivity. Thorax30(3), 337–343. when exercise physiology researchers observed that the length of time individuals could comfortably hold their breath before feeling the urge to breathe was an effective and practical test to determine relative breathing volume during rest and breathlessness during exercise. 

And thus, the BOLT Score Test was born.

A sign next to a yoga mat and bed that says inhale exhale.

Why The BOLT Score Is A Better Measure Than A Standard Breath Hold

When you do breath hold tests that involve measuring how long you can hold your breath, various factors other than just your lung volume and function come into play, which can conflate your results. 

For example, someone who has greater willpower or motivation can push through longer than someone whose tidal volume and lung function may be just as good but who doesn’t feel like persevering through the same level of discomfort. 

In this scenario, the differences in motivation and willpower can affect the results. When performed properly, the BOLT Test circumvents these types of variables. 

With the BOLT Score Test, the time the measurement stops should be taken as soon as the first urge to breathe is felt. 

This way, you can get a more accurate assessment of your relative breathing volume and breathlessness during physical activity.

A woman performing the BOLT Score test by holding her breath and covering her nose.

How To Do the BOLT Test 

Performing the BOLT Score Test is simple and requires no equipment aside from a stopwatch, though, in a pinch, you can try to count seconds in your head.

Before doing the BOLT Score Test, you should rest quietly for at least 10 minutes, avoiding any physical exertion.

  1. Sit upright in a comfortable position.
  2. Take a normal breath in and out through your nose.
  3. As soon as you’ve exhaled through your nose, pinch your nose to prevent any air from entering your lungs and start the timer.
  4. Keep the timer running while you hold your nose and do not breathe.
  5. As soon as you feel the first sensation that your body wants you to breathe, stop the timer. Sensations you might feel include involuntary contractions of the diaphragm, the desire to swallow, a constriction of the airway, or a mental urge to resume breathing.
  6. The BOLT Test is now over, and you should let go of your nose and resume normal breathing. 

Note that because you aren’t holding your breath even a second longer than your body would want you to take a breath, your first inhalation after the BOLT Test is over should be completely relaxed and normal.

If you feel like you’re gasping or taking a big deep breath, you pushed past the point of the first sensations of breathlessness and your BOLT score will be inaccurate.

A man with his eyes closed breathing calmly.

How the BOLT Score Test Works

When we breathe, we inhale air that has oxygen for our lungs to extract and use, and we exhale air that has a higher concentration of carbon dioxide. Carbon dioxide can be seen as the waste product of respiration.

Any time you hold your breath, you prevent this gaseous cycle, so oxygen levels in the lungs and blood decrease slightly while carbon dioxide levels increase.

Studies3 Stanley, N. N., Cunningham, E. L., Altose, M. D., Kelsen, S. G., Levinson, R. S., & Cherniack, N. S. (1975). Evaluation of breath holding in hypercapnia as a simple clinical test of respiratory chemosensitivity. Thorax30(3), 337–343. show that carbon dioxide concentration is the primary stimulus for breathing. 

Therefore, your BOLT Score Test score, or the length of time you can hold your breath before feeling the desire to inhale is dependent upon your ventilatory response to carbon dioxide or the concentration of carbon dioxide your body can tolerate.

The more sensitive you are, or the stronger your ventilatory response, the quicker your carbon dioxide threshold will be met and the shorter your hold time will be. This will result in a lower BOLT score. 

The converse is also true: the better your tolerance to carbon dioxide and the more minimal your ventilatory response to carbon dioxide, the longer it will take to feel the urge to breathe and the higher your BOLT Score Test score will be. 

A woman out of breath from running with her hands on her knees.

Why Does Your BOLT Score Matter?

So, why does any of this matter? How does your sensitivity to carbon dioxide affect your athletic performance as a runner? 

As mentioned, a low BOLT score indicates that your breathing receptors are especially sensitive to carbon dioxide. Practically, this means that your breathing volume will be greater or your respiration rate will be faster because the threshold by which the lungs are being signaled to work to remove any excess carbon dioxide by breathing is quite low. 

One study4 found that breath-hold time correlates with VO2 max and anaerobic threshold.

A woman doing breathing exercises by covering one notril.

What Is a Good BOLT Score?

Of course, any sort of test is only valuable when you know how to interpret the results. The BOLT score is simply the number of seconds you lasted before you felt the first inkling to breathe.

According to The Oxygen Advantage, a good BOLT score is 40 or above. However, many athletes start out with BOLT scores around 20, so if you are well below 40, don’t feel discouraged. 

You can increase your BOLT score and reduce your sensitivity to carbon dioxide with breathing exercises.

4 Ways to Increase Your BOLT Score

Much like how strength training makes your muscles stronger, you can gradually increase your BOLT score.

#1: Box Breathing

For example, try performing a simple box breathing exercise a few times a day:

Inhale for 4 seconds, hold the breath for 4 seconds, exhale for 4 seconds, and hold completely exhaled for 4 seconds.

Box breathing can also be used to reduce anxiety, and it can help your body get better at breathing more efficiently.

A woman out of breath from running.

#2: High altitude training

A trick used by elite athletes!

Any sort of physical exercise will improve your well-being and BOLT score result, but high altitude training specifically may also increase your oxygen-carrying capacity, which can reduce breathlessness during exercise.

#3: The Wim Hoff Method

One of the many breathing techniques which improves our CO2 tolerance, breathing muscles, and lung capacity. For more detailed instructions on this method, click here!

#4: Buteyko Breathing

This breathing exercise involves holding your breath at the exhale until you feel an urge to breathe, returning to normal breathing pattern for 10 seconds, then repeating for a few rounds.

As runners, we just love our data, don’t we?

The BOLT test is just another test to tack onto the list of challenges we make ourselves face to track our improvement and work towards our peak performance.

If you are interested in seeing how you stack up with your fitness, you can take a crack at the Cooper Fitness Test or the Army Combat Fitness Test!

Or, you may want to sneak in a lifestyle challenge with The 75 Hard Challenge. Good luck!

A woman looking toward the trees with her arms spread wide.


  • 1
    Home New. (n.d.). Oxygen Advantage.
  • 2
    Stanley, N. N., Cunningham, E. L., Altose, M. D., Kelsen, S. G., Levinson, R. S., & Cherniack, N. S. (1975). Evaluation of breath holding in hypercapnia as a simple clinical test of respiratory chemosensitivity. Thorax30(3), 337–343.
  • 3
    Stanley, N. N., Cunningham, E. L., Altose, M. D., Kelsen, S. G., Levinson, R. S., & Cherniack, N. S. (1975). Evaluation of breath holding in hypercapnia as a simple clinical test of respiratory chemosensitivity. Thorax30(3), 337–343.
  • 4
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Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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