Winter Training
The obvious goal of any training process is to develop a certain skills. At the same time the correct choice of the type and level of loads to be overcome is the main condition as ensuring the most useful circs in which classes are gonna take place in. It's unlikely anyone will argue with this statement.
Let's consider for example two aspects of such conditions, namely, air quality and temperature. Breathing is one of the most important physiological processes since all other functionalities are directly dependent of it. How and what you breathe will affect on your health, thinking and almost everything else (as a derivative of the first two).
Swimming Under the Ice
Temperature. In our country we've got generally accepted (especially for the older generation) desire to warm children as much as possible at almost any time of the year, that causes children to breathe "warm dust" all the time (at school, at home, and in extra classes): absolutely stale air, saturated with carbon dioxide, dust and bacteria/viruses. Prolonged exposure in such conditions leads to atrophy of the natural mechanisms of thermoregulation, reduced immunity, loss of mental and physical potential.
Reaching out to the voice of reason at the public level is quite problematic, therefore, your health and the health of your children must depend fully and only on you, ain't on the generally accepted absurd standards approved with the sole purpose: to minimize the responsibility of education officials (teachers, educators) and ensure 'em relaxed retirement.
The bottom line
Throughout the year, regardless of temperature and weather conditions, it's extremely important and necessary to regularly perform physical exercises outdoors, exposing yourself to low temperatures, and to ensure a constant flow of fresh air in all locations where you are for a long time.
Naturally, the implementation of such goals should be carried out consistently and very carefully, taking into account the individual characteristics in each particular case.
The implementation of these recommendations will lead to a significant improvement in health and, as a result, an improvement in the ability to solve various mental and physical problems.