Fever in children: how to measure it and respond appropriately
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We climb stairs, go for walks, carry our shopping home and exercise … Yet we rarely stop to think about the important role our lungs play in these everyday activities. With every breath, they constantly ensure that oxygen enters the blood. The blood then transports it to wherever it is needed. In other words, our respiratory health is essential to our well-being and physical performance. However, a decline in lung health rarely becomes noticeable overnight; after all, few people use their lungs to their full capacity in everyday life.1 Anyone who wants to keep an eye on their respiratory health should therefore pay attention not only to obvious breathlessness, but also to changes in their ability to cope with physical activity and understand how to interpret vital signs such as oxygen saturation.
Measuring and understanding oxygen saturation
Put simply, oxygen saturation (the SpO2 reading) describes the oxygen level in the blood. In medical terms, it indicates the percentage of haemoglobin, the red blood pigment, that is carrying oxygen. In most healthy people, oxygen saturation is between 95 and 100%.2 It is measured using a pulse oximeter placed on a finger. Important: A single reading never tells the whole story. For example, people with certain heart or lung conditions, such as long COVID, may have lower individual readings. Spending time at higher altitudes can also affect oxygen saturation.2 The following table therefore provides general guidance for adults.
| SpO2 reading | Interpretation |
| 95 – 100% | Normal oxygen level: Indicates an adequate oxygen level in the blood. |
| 90 – 94% | Low oxygen level: Watch for any symptoms. Consulting a doctor is recommended. |
| Below 90% | Critically low oxygen level: Consulting a doctor is strongly recommended. |
Shortness of breath and other symptoms: When your breathing changes
Do you need to catch your breath after sprinting to the bus stop, or find yourself out of breath on a hiking holiday? This is usually perfectly normal. It is a different matter, however, if activities you previously managed without difficulty suddenly become challenging. Perhaps you suddenly need a break halfway up the stairs, become short of breath on your usual walk, or notice that respiratory symptoms such as a cough simply will not go away. Of course, these changes can have many causes. However, new or worsening shortness of breath, a persistent cough, sputum or wheezing should always be assessed by a doctor, for example to rule out chronic obstructive pulmonary disease (COPD).1,3
COPD: When lung function changes gradually
It is estimated that around five to ten out of every 100 people over the age of 40 have COPD, with men affected significantly more often than women. COPD causes permanent damage to the lungs, accompanied by chronic narrowing of the bronchial tubes. Smoking is the biggest risk factor. Evidence now shows that using e-cigarettes can also contribute to the development of COPD,4 as can heavy exposure to certain types of dust in the workplace.1 Because the disease progresses very slowly, COPD symptoms such as breathlessness, a persistent cough, sputum and whistling or low-pitched wheezing sounds when breathing are often initially ignored or attributed to minor infections. Many patients are therefore already over the age of 60 when they are diagnosed with COPD.
Measuring oxygen saturation: When further tests are important
Regularly checking oxygen saturation can provide additional insight into the body's oxygen supply. However, an SpO2 reading alone cannot reliably determine or rule out whether sudden or recurring respiratory symptoms are caused by COPD. If COPD is suspected, a lung function test (spirometry) is therefore particularly important.1 During the test, you breathe into a spirometer through a mouthpiece. This special device measures how much air you breathe out and how quickly it leaves your lungs.5 The test can often be carried out at your GP practice. If the suspicion of COPD is strengthened or further tests are needed, you will usually be referred to a respiratory specialist.1
Precisely because COPD often develops gradually, recognising and investigating possible signs early is particularly important. World COPD Day also helps raise awareness of the condition. Held every year on the third Wednesday in November since 2002, the initiative is organised by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). It aims to raise awareness of COPD worldwide, share knowledge and help reduce the burden of the disease.
Keep an eye on your readings: Start today!
Whether or not you have COPD, taking an active interest in your respiratory health is worthwhile at any age. Regularly monitoring vital signs such as oxygen saturation, heart rate and circulation, and recognising changes early, can help you better understand developments in your health.
Sources:
1) Federal Ministry of Health: Chronic obstructive pulmonary disease (COPD). gesund.bund.de
2) U.S. Food and Drug Administration (FDA): Pulse Oximeter Basics
3) World Health Organization (WHO): Chronic obstructive pulmonary disease (COPD)
4) German Lung Foundation (Deutsche Lungenstiftung e. V.): Why e-cigarettes are unsuitable for smoking cessation
5) Federal Ministry of Health: Spirometry. gesund.bund.de
