Your lungs might be your biggest untapped performance lever. Dr. Andrew Sellers breaks down why most cyclists have a respiratory limitation they don't know about—and how you can train your breathing patterns on your couch to unlock 6-10% gains in FTP without ever touching your bike.
Key Takeaways
- Respiratory limitation is often invisible but measurable: CO2 management, not oxygen availability, is the primary driver of breathing rate during exercise, and many cyclists unknowingly have a respiratory ceiling that limits their power output.
- Breathing can be trained independently of leg work: You can develop respiratory capacity during threshold-intensity breathing sessions while resting, then apply those gains to your cycling without fatiguing your muscles or cardiovascular system.
- Diaphragmatic nasal breathing recruits more respiratory muscle: Breathing through your nose stimulates the opposite-side diaphragm and allows larger tidal volumes than mouth breathing, which is why World Tour riders use nasal patches.
- Professional cyclists are already using respiratory training: A 48-week study of pro cyclists showed 6-8% FTP improvements and 10% gains in maximum lung volume—but most aren't publicly discussing their protocols.
- Heart rate variability is directly manipulated by breathing rate: Slower breathing increases HRV because deeper breaths pull more blood into the chest cavity, stretching the heart more and allowing stronger contractions.
- Exercise-induced asthma is typically a breathing pattern problem, not a lung problem: Dysfunctional hyperventilation during hard efforts causes turbulent airflow irritation; controlled nasal breathing eliminates most symptoms.
Expert Quotes
"The major driving force for you to breathe is CO2. That's why when you hold your breath, if you have a pulse oximeter on, which measures how much oxygen's in your blood, you can hold your breath for as long as you want. Your oxygen saturation won't drop, but you will have a desperate desire to breathe. And it's not because your oxygen level is dropping. It's because your CO2 levels climbing. — Dr. Andrew Sellers"
"When your breathing gives out, you won't be able to push as hard on the legs. And so now your performance will drop off because your breathing can't keep up. But you can train the breathing for 6 weeks and actually do better in that training session because your respiratory system is no longer the limitation. — Dr. Andrew Sellers"
"The best way to improve your heart rate variability is to slow your breathing down. — Dr. Andrew Sellers"