Do you suffer from shortness of breath during physical exertion or even when speaking and at rest? No doctor can find a cause and help you? Here you can learn more about the importance of reduced respiratory muscle strength and apnea tolerance and how you can improve your performance!
Weak respiratory muscles and decreased apnea tolerance are almost always underestimated as causes of shortness of breath by physicians and physical therapists.
Especially after an illness, such as a corona infection, a restriction of physical performance often persists. The main symptom is exertional dyspnea. Since the complaints do not get better, you visit the family doctor and various specialists. Often the cause is not found and you are left to fend for yourself.
In Cardiopraxis® we experience on a daily basis that a limitation of respiratory muscle strength and a reduced apnea tolerance are very often a cause of shortness of breath and can thus provide targeted help.
Dyspnea and shortness of breath - cause often not found
The term dyspnea (ancient Greek: "δυσ" "dys" "difficult" and "πνοή" "pnoe" "breathing") is usually equated in German with shortness of breath, breathlessness, air hunger and shortness of breath. In simple terms, shortness of breath means a mismatch between your body's need for gas exchange, that is, an intake of oxygen and a release of carbon dioxide, and the supply of air through the lungs, that is. In short, with shortness of breath the demand is greater than the supply.
Typically, we know shortness of breath when we are physically exerting ourselves and accordingly the severity of shortness of breath is also divided into shortness of breath at:
- heavy physical load
- moderately heavy physical load
- light physical load
- at physical rest and when speaking
Shortness of breath during physical exertion can also be distinguished from shortness of breath at rest and during speech, which we can then also call shortness of breath. Shortness of breath is characterized by shallow and rapid breathing, occurs at rest, especially after meals, and is usually associated with problems with speech.
In the entire outpatient medical care sector, approximately 25% of patients suffer from shortness of breath of all degrees of severity. In some specialties, such as cardiology, the figure is up to 50%. Despite extensive clarification by general practitioners and specialists, a cause is not found in 30-50% of affected people and they are left to fend for themselves.

Family physicians, internists, pulmonologists, cardiologists, physical therapists - respiratory muscle strength is not measured
People with shortness of breath have often had a purely months-long odyssey through the medical system. If you suffer from shortness of breath, the first place you usually go to seek help is your family doctor.
Primary care physician. You first describe your symptoms in detail to your family doctor, who then gives you a thorough physical examination. He measures your blood pressure s well as your heart rate and performs laboratory tests to rule out anemia or an infectious disease, for example.
If the primary care physician cannot find a cause for the shortness of breath, then he or she will usually give you a referral to a pulmonary specialist and a cardiologist, usually in that order.
Pulmonologist. You first describe your symptoms in detail to the lung specialist and he then examines you thoroughly physically. He will perform the usual measurement to determine the width of the airways and the volume of the lungs, spirometry. CO transfer (conductivity of the lungs for blood gases), blood gas analysis and an X-ray of the lungs may be performed. If the pulmonary specialist finds nothing, then he will refer you to the cardiologist and may give you an asthma spray.
Cardiologist. You first describe your symptoms in detail to the cardiologist and he then examines you thoroughly physically. He performs the usual measurements ECG, stress ECG and heart ultrasound. If the cardiologist has not found anything, he will send you back to your family doctor.
Physical therapists. In rare cases, you will be referred to a physical therapist for respiratory training. There, almost always only tensions are released in order to increase the lung volume and facilitate breathing. There is no targeted training of respiratory muscle strength or even apnea training.

Limitation of respiratory muscle strength often unrecognized reason for shortness of breath
As already mentioned, 30-50% of people with shortness of breath go down this sometimes very lengthy path without a tangible cause for the shortness of breath having been found. Not infrequently, you have to listen to comments such as: "you are too fat", "you have to move more", "you are already older", "maybe it is also Long-COVID", "maybe it is also psychosomatic" and, and, and. In the end, you are pretty much alone with your shortness of breath: not recognized and not treated.
Was gemäß eigenen Erfahrungen bei dieser Kaskade an medizinischen Maßnahmen in >99% der Fälle nicht geschieht ist eine Messung beziehungsweise richtige Bewertung der Atemmuskelkraft und der Apnoetoleranz. In der Cardiopraxis weisen nach Ausschluss aller anderen Ursachen 60-80% der symptomatischen Patienten eine unterdurchschnittlich Atemmuskelkraft und/oder eine verkürzte Atemanhaltezeit bis zum ersten Atemantrieb nach entspannter Ausatmung von <20 Sekunden auf.
The cause of the restriction of respiratory muscle strength is in almost all cases an incorrect breathing technique with shallow mouth-to-chest breathing. Mouth-to-chest breathing leads to muscular weakening of this main respiratory muscle via insufficient strain on the diaphragm and is simply a bad habit.
Respiratory muscle strength - measure, evaluate, train
Measurement of respiratory muscle strength is very rare, although medically approved so-called "stand-alone" devices starting at 1,500 euros are available on the market, for example the MicroRPM. These devices could easily be used by general practitioners, internists, pulmonary specialists, cardiologists, as well as anesthesiologists and surgeons in preparation for surgery. Such measurement also makes sense for physiotherapists in order to specifically improve the performance of the people under their care.
In some cases, respiratory muscle strength measurement is also integrated into larger devices used by pulmonary specialists to determine other lung parameters.
Besides the fact that respiratory muscle strength measurement is almost not used and the health disorder is not recognized, the ignorance of comparative reference values is a problem. However, there are scientifically established measured values.
Mean Inspirational Power Related to Age and Gender
- Men = 120 - (0.41 x age) cmH2O
- Women = 108 - (0.61 x age) cmH2O
Mittelwert Expirationskraft bezogen auf Alter und Geschlecht <100%
- Men = 174 - (0.83 x age) cmH2O
- Women = 131 - (0.68 x age) cmH2O
Values below the mean are to be classified as requiring treatment or therapy. A problem with these mean values is that body size and weight are not included in the assessment, although they have considerable relevance. People of above-average height and weight in particular are more likely to need treatment. Here, formulas must still be scientifically developed in the future that include the aspect of body length and body mass.
Respiratory muscle training is very, very rarely prescribed, although gymnastic exercises exist for this purpose and exercise equipment is commercially available. Exercise equipment is used almost exclusively in post-operative rehabilitation. When respiratory therapy is prescribed, physiotherapists are almost exclusively limited to relieving tension and expanding lung volume.
Reduced apnea tolerance - measure, assess, train
Die Apnoetoleranz ist mit Atemanhalte-Test nach entspannter Ausatmung leicht selbst messbar. Bei Werten < 20 Sekunden ist ein Training erforderlich. Das Apnoetraining kann durch einfache Atemmuster mit in Ruhe oder beim Gehen im Alltag ganz beiläufig geübt werden und führt rasch zu Erfolgen.
Practical procedure for people with shortness of breath and suspected respiratory muscle weakness and/or limited apnea tolerance
If you suspect that you have a respiratory muscle weakness or impaired apnea tolerance, you are pretty much on your own at first, because doctors and physiotherapists will not help you in most cases, so you usually have to help yourself.
The basis of any self-help for shortness of breath is that lung disease and cardiovascular disease, including poorly controlled high blood pressure, are medically excluded as the cause of shortness of breath. Therefore, you cannot avoid a visit to a pulmonologist and a cardiologist.
Optimal procedure for respiratory muscle weakness and limited apnea tolerance
The optimal situation is when respiratory muscle weakness or limited apnea tolerance is proven by measured values.
Based on the measured values, respiratory muscle training and/or apnea training can then be carried out under medical supervision (doctor, physiotherapist). This helps to prevent errors, especially in people with many years of incorrect breathing; older people in particular need a lot of attention and guidance here.
The therapy is then monitored by repeated determination of the measured values and targeted adjustment of the therapy.
Suboptimal procedure - Self-help training of respiratory muscle strength and apnea tolerance.
If no one can (or will) help you from a medical point of view, relevant pulmonary and cardiovascular diseases medically excluded, then you can go about helping yourself.
First of all, you should learn pure nasal diaphragmatic breathing into the abdomen, that is, inhalation and exhalation only through the nose, and perform it in all life situations. Add to this an active walking with more body tension in everyday life.
You can measure a limitation of apnea tolerance yourself with the breath-hold test after relaxed exhalation. You can increase this apnea tolerance with simple exercises.
You can start training the respiratory muscles with simple exercises. The principle here is a use of guiding resistances, for example, sitting with a pillow or a medicine ball and gymnastics with reverse positions, for example, shoulder bridge.
Apparatus respiratory muscle trainers are well suited for increasing respiratory muscle strength. Here there are very simple and inexpensive devices that are available online or in medical supply stores.
However, our experience at Cardiopraxis shows that repeated metrological determination of respiratory muscle strength is very helpful for fully exploiting your individual potential. The AiroFit Pro offers you, in addition to the app-controlled program for increasing apnea tolerance and respiratory muscle strength, the corresponding measurement options for determining the maximum inhalation force and exhalation force. These measured values are comparable with the results of the medically approved devices.
Also pay attention to side effect when doing respiratory muscle training, you should avoid "over training". The training sessions should be designed so that you are slightly strained, but not exhausted.
Respiratory muscle training can also be done very successfully to improve performance for cardiovascular and pulmonary diseases, such as hypertension, low blood pressure, drowsiness, heart failure and chronic obstructive pulmonary disease. However, this should be done under medical supervision.