Understanding Oxygen Saturation: How to Use A Pulse Oximeter and What You Need to Know for Lung Health and Fitness
In recent years, especially during the COVID-19 pandemic, pulse oximeters have become a common tool in many households. These small, fingertip devices measure your blood oxygen saturation (SpO₂) and heart rate, providing a quick glimpse into how well your lungs and heart are delivering oxygen to your body. Whether you have asthma, COPD, emphysema, or are simply interested in monitoring your fitness, understanding how to use a pulse oximeter during exercise can help you exercise safely, recognize warning signs early, and optimize your workouts.
What Is Pulse Oximetry and Why Is It Useful?
Pulse oximetry is a non-invasive method to measure how much oxygen is in your blood. Oxygen-rich blood absorbs light differently than blood without oxygen. The pulse oximeter uses this difference to calculate the percentage of your red blood cells that are carrying oxygen. This is call your oxygen saturation (SpO₂). Normal SpO₂ values for a healthy person typically range between 95% and 100%. Values below this may indicate that your body is not getting enough oxygen.
During exercise, your muscles require more oxygen, so your body works harder to increase oxygen delivery by breathing in more oxygen, increasing the heart rate, and by augmenting the amount of blood that is expelled from the heart with each heart beat. Monitoring SpO₂ during exercise can help you detect if your oxygen levels drop abnormally, which is particularly important for people with lung diseases or heart conditions.
Why Exercise Matters for Lung Conditions
Living with asthma, COPD, or emphysema can make even everyday activities feel like a workout. While exercise cannot reverse the structural changes to the lungs or restore lost lung capacity, it can help you do more with the lung function you have.
When you avoid physical activity, your muscles weaken and your heart becomes less efficient. This can create a cycle of deconditioning, making you even more short of breath during normal activities. Regular physical activity improves how efficiently your body uses oxygen and removes carbon dioxide by boosting cardiac output (heart’s pumping ability), widening the arterial–venous oxygen difference (your muscle’s ability to take in oxygen), and increasing muscle efficiency. The result is less breathlessness, greater stamina, and an improved ability to handle daily tasks — from climbing stairs to enjoying time with friends.
Understanding Heart Rate and Training Zones
In addition to SpO₂, pulse oximeters also display your heart rate, which can help you monitor exercise intensity. To determine exercise training ranges first estimate your maximum heart rate by subtracting your age from 220. Next, measure your resting heart rate with your pulse oximeter by taking your heart rate after 5 minutes of seated rest. From this, you can calculate your heart rate reserve (HRR) which is simply the difference between your maximum and resting heart rate.
Exercise training zones are often expressed as percentages of HRR:
Light intensity: 30–40% HRR
Moderate intensity: 40–60% HRR
Vigorous intensity: 60–85% HRR
Now multiply the HHR by your chosen intensity, then add in your resting heart rate to determine your training heart rate - the target heart rate you should aim for during exercise to match your chosen intensity.
For example:
Max heart rate = 170 bpm
Resting Heart rate = 65 bpm
HHR: 170-65 = 105 bpm
Chosen intensity = 55% (moderate)
Training Heart rate = 105 x 0.55 + 65
= 123 bpm
Monitoring your heart rate during exercise helps you stay within safe and effective intensity levels and can be especially important for those with chronic conditions or those new to exercise.
What SpO₂ Should You Look For on a Pulse Oximeter During Exercise?
For most people, oxygen saturation should stay above 95% during exercise. However, certain lung or heart conditions may lower this baseline.
According to guidelines from the American College of Sports Medicine and pulmonary health organizations:
95–100% SpO₂: Normal, safe range for healthy individuals
90–94% SpO₂: Mild desaturation; monitor closely and consider reducing exercise intensity
Below 90% SpO₂: Indicates significant desaturation; stop exercising and seek medical advice
For people with chronic lung diseases such as asthma, COPD, or emphysema, clinical guidelines from the American Thoracic Society (ATS) define the following thresholds:
SpO₂ ≥ 88%: This is generally considered the minimum safe limit to continue exercising without supplemental oxygen.
SpO₂ < 88%: Exercising below this level is typically contraindicated or requires supplemental oxygen, as it may cause significant hypoxemia (medical term for an inadequate level of oxygen in the blood) leading to adverse effects.
If your SpO₂ falls below 88% during exercise, it’s important to stop, rest, and consult your healthcare provider. They may recommend supplemental oxygen or adjustments to your exercise program.
Using Pulse Oximetry If You Are on Supplemental Oxygen
If you use supplemental oxygen due to advanced lung disease, monitoring your oxygen saturation during exercise is especially important. Pulse oximetry helps you ensure that your oxygen flow rate meets your body’s demands as you become more active. While exercising, keep your SpO₂ readings within the target range set by your healthcare provider—often above 90%—to avoid hypoxemia (low blood oxygen). If you notice your saturation dropping below your prescribed target despite using supplemental oxygen, this may indicate the need to adjust your oxygen flow rate or modify your activity. Always carry your oxygen device and pulse oximeter with you during exercise, and report any consistent desaturation or symptoms such as dizziness or chest discomfort to your medical team promptly.
Important considerations:
Your healthcare provider may give you specific SpO₂ targets tailored to your condition.
Some individuals with advanced lung disease may have baseline saturations below 90% and require supplemental oxygen during activity.
Always use your pulse oximeter in a well-lit, warm environment for accurate readings. Cold fingers or poor circulation can affect results.
Medication type and timing of dose may influence heart rate readings on pulse oximeter.
Tips for Accurate Pulse Oximeter Use During Exercise
Ensure your hand is warm and relaxed during measurement.
Remove nail polish or artificial nails that may interfere with the sensor.
Sit still or stand calmly for 30 seconds before taking a reading.
Compare readings with how you feel — symptoms matter more than numbers alone.
When to Follow Up With Your Healthcare Provider
Seek medical attention if you notice any of the following during or after exercise:
SpO₂ readings consistently below 88%
Sudden onset of chest pain, severe breathlessness, or dizziness
Persistent fatigue or confusion
Irregular or unusually rapid heart rate
Signs of low oxygen: dizziness, confusion, rapid heartbeat, blue lips/fingertips, or sudden breathlessness.
Medication Tips for Individuals with Chronic Lung Conditions
Short-acting bronchodilators (e.g., salbutamol/albuterol) are often used before activity to open your airways.
Long-acting inhalers keep your symptoms controlled day-to-day — take them as prescribed.
Steroid inhalers reduce inflammation and should not be skipped.
Always talk to your healthcare provider before changing your medication routine.
Pursed-Lip Breathing
Pursed lip breathing is a controlled breathing method that can help people with lung conditions breath more easily, especially during activity. To do it, inhale slowly through your nose for about 2 seconds, then exhale gently through pursed lips - as if you are gently blowing out a candle for about 4 seconds. This technique keeps your airway open longer during exhalation allowing you to expel more carbon dioxide. The damaged or narrowed airways that are the hallmark of lung disease collapse too soon during exhalation so not all the air is expelled, so carbon dioxide builds up and fresh oxygen can’t get in as efficiently. Pursed-lip breathing creates back pressure in the airway and can reduce carbon dioxide build-up. This can lessen the sensation of breathlessness since rising carbon dioxide levels are a powerful trigger for the brain to increase breathing effort.
Summary
Pulse oximetry is a simple, accessible tool that can enhance your safety and confidence during exercise, especially if you have lung conditions like asthma, COPD, or emphysema. By understanding your oxygen saturation and heart rate, you can better manage your activity levels, recognize early signs of trouble, and work toward safer, more effective workouts.
If you want personalized advice on using pulse oximetry during exercise, or a tailored exercise program for lung health, the Online Exercise Clinic is here to help. Book a consult today and take control of your health.
