Activity trackers have been developed to measure respiratory rate during the night through gentle arm movements. This measurement helps to detect the early stages of a disease.
- A normal respiratory rate is around 12 to 18 breaths per minute during sleep.
- Breathing less than six times per minute is a stronger indication of a life-threatening heart problem.
- The slight arm movements, recorded using a bracelet, allow more precise conclusions to be drawn on the respiratory rate than the ECG.
The quality of sleep is a good indicator of a person’s state of health. The measurement of this quality passes in particular by the observation of the respiratory rate. To measure it accurately, German researchers have developed an activity tracker that relies on slight arm movements that track respiratory rate. They presented their results on September 3 in the journal Nature.
Develop a lean measurement system
Several previous studies have shown that deviations from a normal respiratory rate, which is around 12 to 18 breaths per minute, can be a sign of serious illness. Breathing less than six times per minute is a stronger indication of a life-threatening heart problem. Conversely, very rapid breathing can be an early sign of heart problems. “Nevertheless, the relevance of respiratory rates in the early detection of medical risks has received little attention.”, wondered Dr. Jan Kantelhardt, physicist and lead author of the study.
For several years, the team of German researchers has been studying how physical data from measuring devices can improve patient diagnosis. Currently, reliable measurement of respiratory rates over longer periods of time is only possible in clinics that have the right equipment. Until now, a standard electrocardiogram (ECG) has often been used to measure heart rates and rhythms, allowing conclusions to be drawn about breathing. “We were looking for a new inexpensive way to measure respiration”, replaces Jan Kantelhardt.
Arm movements, more precise than an ECG
Researchers have turned to special activity trackers to see if they can provide a reliable alternative to ECGs. In the form of a bracelet, these trackers record arm movements. “They are like fitness trackers but much more accurate. We may use our own software to analyze the raw data”, says Jan Kantelhardt. The researchers compared the data collected to that taken by an ECG on 400 patients.
The results showed that slight arm movements allow more accurate conclusions to be drawn about respiratory rate than the ECG recorded at the same time. “If there is too much movement, breathing can no longer be measured with the armbands. But there are always periods of night when we can observe respiration very reliably.”, decrypts Jan Kantelhardt. According to the researcher, the armbands could be used, for example, as a diagnostic tool before sending a patient to a sleep laboratory.
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