The Modern Concepts of Energy Balance and Energy Availability in Sports

The imbalance between energy intake and total energy expenditure is the cause of a negative energy balance and, in combination with prolonged intense physical activity, can lead to the development of low energy availability (LEA). The concept of LEA is associated with several endocrine, cardiovascular, inflammatory, gastrointestinal, and mental characteristics, which have been combined under the term Relative energy deficiency in sports (RED-S). Our analysis of the world literature has shown a high prevalence of LEA and RED-S against the background of insufficient awareness of coaches and athletes about energy deficiency and its negative health consequences, which emphasizes the importance of this problem. That is why the issues of early diagnosis, adequate treatment, and prevention of RED-S, taking into account the specifics of the sport, gender, and age, are of great practical importance.