Why Oxygen Saturation Is NOT the Only Thing That Matters in COPD

I found this on facebook today and found it very helpful. It comes from a young physiotherapist by the name of Viyank Krnaval on the "COPD
Day to Day Living" group.

Why Oxygen Saturation Is NOT the Only Thing That Matters in COPD
I’ve noticed some confusion in the group about oxygen saturation (SpO₂), so I want to clear this up.
Many people focus only on the number on the pulse oximeter. While oxygen saturation is important, it is not the only indicator of how a COPD patient is doing.
I see this very often in clinical practice.
A patient can have normal oxygen levels (94–98%) and still feel extremely breathless. Why?
Because breathlessness in COPD depends on several factors:
1️⃣ Muscle strength
COPD patients often lose muscle mass due to inactivity or hospital stays. Weak muscles require more oxygen during activity, which increases breathlessness.
2️⃣ Lung mechanics
Air trapping and hyperinflation make it harder to move air in and out, even if oxygen saturation looks normal.
3️⃣ Endurance and conditioning
If you avoid activity because of breathlessness, the body becomes deconditioned. This creates a vicious cycle: less movement → weaker muscles → more breathlessness.
4️⃣ Breathing pattern
I frequently see patients breathing inefficiently (upper chest breathing, fast shallow breaths), which worsens symptoms even when oxygen is okay.
Another important point is oxygen targets in COPD.
For most COPD patients, the ideal oxygen saturation range is around 88–92%. Many people think oxygen should always be 100%, but that is not the goal in COPD patients who require supplemental oxygen.
If oxygen is given excessively and saturation is pushed too high (for example close to 100%), it can sometimes reduce the drive to breathe and also worsen CO₂ retention (hypercapnia).
That’s why we usually titrate oxygen carefully instead of trying to make the saturation 100%.
This is exactly why pulmonary rehabilitation is so important. It focuses not just on oxygen numbers but on improving breathing mechanics, endurance, and muscle strength so patients can function better in daily life.
I work with respiratory patients everyday and often see patients improve their walking ability and breathlessness even when their oxygen numbers stay the same.
So remember: don’t judge your lungs only by the pulse oximeter.