When we sleep, breathing is automatic. Our primal brain provides our lungs with the perfect breathing rate to support our resting bodies. What does this imply?
What do we know about breathing during sleep?
During the day, our breathing rate reflects what we do — both consciously and unconsciously. When we sleep, breathing reflects what is going on inside us — it is entirely controlled by the autonomic nervous system via the respiratory center in the brainstem. Can we use this knowledge to learn more about our general health?
Our body works constantly to stay in equilibrium. Many different regulation mechanisms maintain our body temperature, balance salt, regulate our hormone balance, energy balance, fluid balance, blood pressure, pulse, pH, respiration and more.
This is why the human body is extremely adaptable and can survive very different influences — extreme cold, extreme heat, extreme altitude, extreme activity, extreme nutritional conditions, injuries and illness.
Vital signs are medical observations that can summarize the vital functions of our bodies.
The 4 most important are:
- Temperature (Normally 36.5-37.5 C)
- Blood pressure (Normally <140/90)
- Heartrate (Normally 50-100)
- Respiration rate (Normally 12-20)
Why is respiration rate more difficult to measure than heartrate?
Humans generally breathe without paying close attention to the act of breathing. Still, by a shift of focus, breathing can also be easily controlled. Just think about when you sing, talk, eat, swim or simply decide to hold your breath or take a deep breath (like the one you just took). As soon as you become aware of your own breathing, the otherwise automatic regulation is affected. It is therefore difficult to measure your own respiration rate by counting.
The best thing would be to measure the breathing rate while it is only regulated by the body's automatic functions — for example in sleep. But how can this be achieved?
Somnofy sleep monitor
The Somnofy sleep monitor is designed to map a number of vital parameters at night — including the respiratory rate. The sleep assistant uses radar technology that provides information about:
Sleep stages (Light, Deep, REM)
Sleep Environment (Room temperature, light, noise, air quality and air pressure)
The monitor can be mounted on a wall or simply placed on a bedside table and is not in physical contact with the user. Somnofy provides the opportunity to learn about your breathing rate while you are completely unaware: during sleep, when your breathing is regulated automatically based on your own fine-tuned "sensors".
In the same way that the resting heart rate varies from person to person, the respiratory rate during sleep is also individual. It remains stable over time if the body is otherwise in stable shape and sleeps in a steady environment. This makes breathing a good measure to record changes in the body.
An increase in breathing rate is not specific. In the first instance it just tells us that the body is doing something out of the ordinary. Typical examples of what may trigger an increase in respiratory rate are infections like the cold or a flu, pain, injuries, inflammation, recent hard strain or certain medication. In seldom severe cases blood poisoning, COPD, kidney failure, and other diseases can increase the breathing rate at night.
The resting respiration rate physiologically varies between 12 to 20 breaths per minute from one person to another (from 12 to 20, there is an increase of 67%). Therefore, it is almost impossible to decide whether the breathing rate is "normal" if you only measure at one time point. For someone who is normally at 12, a one time measurement of 20 will be a dramatic increase. For someone who is normally at 19, an increase to 20 will be insignificant. Regular nocturnal measurements thus show an individual's baseline value and sudden changes or gradual changes over time can be easily spotted.
An example of how breathing can detect infection in the body:
The picture shows how a steep incline of the breathing rate graph can help detect an infection in a patient’s body. We can visually determine the sudden increase from 17 to 23 breaths per minute on average during the night — an increase of 35%. This person felt sick the next day and showed clear signs of infection upon clinical examination. A blood sample confirmed very high infection markers (CRP 135) and immediate antibiotics therapy was introduced against the symptoms of a urine tract infection. After therapy onset the patient quickly returned to the baseline breathing rate at night and fully recovered.
New technology — new opportunities
The Somnofy technology opens up the possibility to keep track of one of the most important vital signs over time — breathing rate while sleeping. Any Somnofy user can follow this parameter on their own or do so together with family members or healthcare professionals. This offers an increased feeling of security to actually spot changes in health status early, before they develop into a serious sickness. As a medical doctor, I am especially interested in following nightly breathing rate among these patient groups:
Discharged patients post surgery — Are there signs of wound infection?
Home-dwelling elderly and dementia patients — Did their health status change which they cannot report?
Injured patients — Are there signs of severe pain levels?
Patients with a known infection — Are infection levels rising? Is there risk of sepsis?
COPD patients — Can we see clearly worsening symptoms/pneumonia?
Heart failure patients — Is the breathing rate increased due to fluid in the lungs?
COVID-19 patients — Is the breathing rate markedly increasing during home quarantine?
When I ask: «How are you?», and you respond by stating that your respiration rate is normal — I will take this as a good vital sign!