The 6-minute walk test is currently the most common, well-standardized, and readily available stress test. The test uses an arbitrary walking speed, while the patient is asked to walk at his own pace as fast as he can and walk as long as possible for 6 minutes on a flat surface (along a corridor measured [30 m] and marked after 1 m, a sports ground), after which the distance traveled is recorded. Patients are allowed to stop and rest during the test; they should resume walking when they deem it possible. While walking, it is recommended to encourage patients with standard phrases: “Everything is going well”, “Continue at the same pace”.
Shortness of breath (on the Borg scale or visual analog scale), pulse rate (PR), breath frequency (BF), and SpO2 should be assessed before and at the end of the 6-minute walk test. 
Pulse rate is important for 6-minute walk test results. Using Pulsar pulse oximeter in the stress testing mode allows controlling pulse rate throughout the entire test, to record the maximum pulse rate, as well as the dynamics of its recovery after the end of the test.
In turn, continuous measurement of SpO2 during a 6-minute walk test reveals desaturation during exercise in patients who have normal gas exchange rates at rest. Desaturation refers to a decrease in SpO2 during a 6-minute walk test by more than 4% of baseline or below 90%. Exercise desaturation is associated with lower daily physical activity, a more rapid decline in lung function, and a poor prognosis for the course of a disease.
The use of Pulsar pulse oximeter directly during the 6-minute step test allows continuously monitoring the SpO2 and pulse rate level with the determination of the desaturation index during testing and the possibility of detecting latent respiratory failure.
In turn, a reliable SpO2 measurement is possible only in a clearly traceable pulse wave, the quality of which is indicated by color in Pulsar pulseoximeters – from light green with a high value of the perfusion index to red with its unsatisfactory decrease. The latter situation is most often observed in patients with lung damage on the background of systemic scleroderma or with other pathologies of peripheral vessels, vasoconstriction, a decrease in the stroke volume of the heart, and internal bleeding. Stress tests can also include testing on a bicycle ergometer, treadmill, procedures in a pressure chamber, “Mountain Air” procedure, which are widely used in spa medicine.
Stress tests, and among them the most accessible, well-standardized and widely used 6-minute step test, play an important role in the clinical practice of identifying reserve physical capabilities of the patient, as well as in assessing the effectiveness of therapy for bronchopulmonary diseases.