Your BOLT Score, Why it Matters and How to Improve It

When it comes to improving wellbeing, focus, and physical performance, the BOLT score (Body Oxygen Level Test) is one of the simplest yet most revealing metrics you can track.

It provides insight into your breathing efficiency, CO₂ tolerance, nervous system regulation, and oxygen delivery — all key drivers of energy, resilience, and long-term health.

In this guide, we’ll explain what the BOLT score is, why it matters, and how you can improve it using practical, science-led strategies. Most importantly, you’ll see why breathing efficiency reflects how well your entire system is functioning.

If you haven’t measured your BOLT score yet, you can learn how to do so here.

What Is the BOLT Score and Why Does It Matter?

The BOLT score isn’t just a number, it’s an insight into how efficiently your body breathes, delivers oxygen around the body and adapts to stress.

It measures how long you can comfortably hold your breath after a normal exhale and is closely linked to:

• Respiratory health

• Carbon dioxide (CO₂) tolerance

• Nervous system balance

• Oxygen delivery efficiency

Together, these determine how well you perform, recover and can regulate well under pressure.

Why does improving your BOLT score make a meaningful difference?

• Respiratory Health and Oxygen Efficiency

A higher BOLT score indicates more efficient breathing and better oxygen utilisation. This means more energy, improved endurance and a calmer baseline; all essential for modern daily life.

• Carbon Dioxide Tolerance

CO₂ is often misunderstood as a waste gas and has a bad rep, but it’s essential for oxygen delivery.
Without enough CO₂ the oxygen binds too tightly to the blood and struggles to reach cells around the body.

A higher BOLT score suggests healthier CO₂ tolerance, supporting energy production, metabolic health, focus and stamina.

• Stress and Anxiety Regulation

Chronic stress often leads to dysfunctional breathing: shallow, rapid or mouth breathing. This chronic hyperventilation lowers CO₂ levels and disrupts nervous system regulation.

Retraining your tolerance to CO₂ through slower breathing helps reset this feedback loop, making us calmer, less reactive and more adaptable under pressure.

• Quantifiable Progress

Your BOLT score provides a measurable way to track physiological change. Whether your goal is calm, clarity, or performance, watching this number improve is both motivating and validating.

• Performance and Endurance

For active individuals, a higher BOLT score often correlates with improved stamina and reduced breathlessness. It’s a subtle but powerful marker of training adaptation.

How to Improve Your BOLT Score

If your BOLT score is below 20 seconds, your body has likely adapted to over-breathing, taking in more air than needed and disrupting CO₂ balance.

HOWEVER this pattern can be retrained and improvements are often seen within days or weeks.

1. Breathe Through Your Nose

Nasal breathing filters, warms, and humidifies air while increasing nitric oxide production, which improves oxygen uptake and CO₂ retention.

During exercise, reduce intensity until nasal breathing feels comfortable. This builds endurance and breathing control.

2. Use Your Diaphragm

Diaphragmatic breathing engages the full capacity of your lungs and slows your breathing rate.
Place one hand on your chest and one on your belly, aiming for the belly to move more.

3. Practice Light, Slow Breathing

Breathe gently through your nose for 5–6 seconds in and out.
Start with 1–2 minutes, 2–3 times per day, gradually increasing the duration.

4. Introduce Breath Holds

Breath holds after a normal exhale help train CO₂ tolerance. Start gently and gradually increase duration. You can also try breath-hold walking, then recover with nasal breathing.

5. Exercise with Nasal Breathing

Keep your mouth closed during low-to-moderate exercise.
When you feel the urge to mouth breathe, you’ve found your current limit. Over time, this limit expands.

6. Using Breath to Help Manage Stress

Even two minutes of slow nasal breathing can shift your nervous system from “fight-or-flight” to “rest-and-recover.”

7. Positive Lifestyle Habits

Posture, sleep, hydration, and sinus health all influence breathing. Small daily habits compound into meaningful change.

When to Seek Expert Support

You may benefit from guided support if:

• You struggle to sustain nasal breathing under stress

• You frequently feel anxious or overwhelmed

• Your BOLT score doesn’t improve after 4–6 weeks

• You experience fatigue or poor recovery despite healthy habits

These are signs your stress and oxygen systems need deeper retraining.

Final Thoughts

Your BOLT score is far more than a breathing test.
It’s a measure of adaptability, nervous system balance, and performance potential.

Improve your breathing efficiency and you unlock more energy, focus, resilience, and clarity; the foundations of modern performance.

Start small. Stay consistent. Let your system recalibrate.

If you’re ready to go beyond breathwork and retrain your energy system at its roots, we can help at KALA