The principle of Doppler ultrasound is based on the Doppler effect, which involves changing the detected frequency of a sinusoidal wave when there is movement between the transmitter and receiver. In recent decades, carotid Doppler ultrasound has been investigated as a non-invasive alternative to invasive hemodynamic monitoring techniques used. The main purpose of the paper was to discuss the architecture of various Doppler systems, as well as to present how this architecture has changed over the years in the context of the possibility of using the measurement method such as Doppler ultrasound of carotid arteries for example in the ability for pilots. The most promising solutions are wireless wearable bands, which, when applied to the neck, will not be a burden during measurements. This is important when measurements are to be taken on people performing certain extreme activities, such as pilots during an orthostatic test with Low Body Negative Pressure (LBNP), a test used to assess the state of the cardiovascular system when changing from lying to standing position. The methodology of the study consisted in searching the PubMed database and Internet resources for literature related to the examination of carotid artery blood flows by ultrasonography, in particular in extreme conditions or during various types of additional interventions. As a result of the work carried out, information was obtained that the carotid Doppler ultrasound method has great potential in supporting activities related to pilot testing, in particular under simulated overload conditions. Doppler ultrasound can be a useful non-invasive tool in the diagnosis of pilot performance, while also acting as a warning function, so-called alerts, against impending overload loss of consciousness.