The research tool is an original questionnaire compiled by a team of experts conducting the study. The survey includes questions about sociodemographic data, such as age and gender and blood type in AB0 system with Rh factor, and questions about the frequency of ice swimming, the duration of a single session, and since when respondents have been ice swimming. There was also a question about the respondents' compliance with the restrictions and recommendations related to the pandemic and contacts with people with confirmed SARS-CoV-2 infection. In the survey, researchers ask about the infectious symptoms experienced during the pandemic and about being diagnosed with COVID-19 or its exclusion. People who have been ill are asked about the place of treatment.
The questionnaires are collected in traditional form, on the Internet and as scans of documents. Each survey was completely anonymous. The obtained statistical data will be compared with official data on new COVID-19 cases and recoveries at the same time. Official data are published by the Ministry of Health and earlier also by Sanitary and Epidemiological Stations. The main aim of the study was to determine whether ice swimming also increases resistance to SARS-CoV-2 and COVID-19.