The Canadian — W. Somerset Maugham

Nora opened her eyes to an unaccustomed consciousness of well-being. She was dimly aware that it had its origin in something deeper than mere physical comfort; but for the moment, in that state between sleeping and wakening, which still held her, it was enough to find that body and mind seemed rested. Youth was reasserting itself. And it was only a short time ago that she had felt that never, never, could she by any possible chance feel young again. When one is young, one resents the reaction after any strain not purely physical as if it were a premature symptom of old age.