The effect of supercompensation and the conditions of its origination have been analyzed using a special analytical solution of the equation of the overdamped Duffing oscillator. The threshold values of the functional shift after the exposure of a living organism to intensive external load have been found. If these values are exceeded, the restoration process goes through the stages of enhanced and lowered working capacity. Expressions for the times of transition to these phases after the onset of recovery and for the time of occurrence of the maxima of these phases have been obtained and analyzed.