Lactate Threshold and Psychomotor Fatigue Threshold in Hot Conditions: Suggestions for Soccer Players Participating in the Qatar World Cup 2022

The study aimed at finding relationships between lactate threshold and psychomotor fatigue threshold during incremental exercise in thermo-neutral climate conditions and conditions for the 2022 FIFA World Cup in Qatar simulated in an environmental test chamber. The study included 24 soccer players aged 21.02 ± 3.22 years old. The following procedures were performed: The incremental exercise test to mark lactate concentration—LA (mmol·l(−1)); Psychomotor test to determine choice reaction time; Designation of the lactate threshold (T(LA)) and psychomotor fatigue threshold (T(PF)). Climate conditions: The procedure was performed twice in the climatic chamber: (1) in thermo-neutral conditions—TNC (ambient temperature 20.5 °C and relative air humidity 58.7%), (2) after 7 days—in Qatar conditions—QC (28.5 ± 1.92 °C) and (58.7 ± 8.64%). It was confirmed that the T(PF), which reflects the highest efficiency of CNS functioning, occurs at a higher running speed than the T(LA). The temperature of 28.5 °C with 58.7% humidity, which is the lower limit of heat stress, causes the psychomotor fatigue threshold to appear at a lower running speed than in thermoneutral conditions. The data recorded in this work may help to understand the specificity of physiological and psychomotor reactions to various climatic conditions.