The aim of the project is to experimentally compare SpO2 measured on a wrist by commercial Smartwach and on a finger measured by a medical-grade pulse oximeter in healthy humans during gradual desaturation in the range of 60-100% SpO2 and simultaneously during a step change from the hypoxic phase to the recovery phase (return to physiological values).

The newest models of smartwatches measure peripheral blood oxygen saturation (SpO2) and the technology is rapidly improving. The results of individual studies on the accuracy of SpO2 measurement using smartwatches from different brands are still inconclusive. The study aims to compare the measurement of peripheral blood oxygen saturation using the latest smartwatch with a medical-grade pulse oximeter under the condition of normobaric hypoxia. SpO2 measurements will be taken by hand from the watch and the pulse oximeter simultaneously. The agreement of the measurements of both devices will be evaluated.

Inclusion Criteria:

• Passing the initial examination, which will determine the following data: finger circumference, heart rate, blood pressure, blood oxygen saturation and medical history

Exclusion Criteria:

• pregnancy
• severe cardiovascular conditions
• severe asthma or other severe respiratory conditions
• injury to the upper limbs or hands that could affect the peripheral perfusion
• diabetes
• hypotension or hypertension