Figure 1.

(A) the design of the room. The resting room is 670 × 350 × 220 cm, about 24 square meters, equipped with beds, TV and dinner table; the working room is 670 × 385 × 220 cm, about 26 square meters, equipped with fitness equipment and computers. The humidity was 35-60%; the temperature was 23.3-26.0 degree. All subjects received sunshine at given period during the restriction. The activity time and sleep time were both more than 8 hours. (B) the design of the blood withdrawal schedule in the morning of the day points; (C) stress triggered serum cortisol increase during the experimental period, showing individual results. (D) the serum cortisol increase normalized to day 0.