Give a definition of hardening and tell us how it is useful.

Hardening is one of the most effective means of strengthening the mechanisms of adaptation of the human body to cold and heat, increasing its resistance to changes in environmental conditions. Hardening weakens or eliminates the negative reactions of the body to weather changes (decreased performance, poor mood, malaise, pain in the heart, joints, etc.).
Regular hardening provides:
• increasing the ability to perceive and remember;
• strengthening willpower;
• activation of physiological activity;
• slowing down the aging process;
• extension of active life by 20-25%.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.