All lifts were done in normal lighting conditions. All light exposure conditions took place in a room 12.8 m by 5.5 m. The room was lit by 15 fluorescent light fixtures each containing four 1.2 m bulbs that produced approximately 2600 lumens per bulb. The light fixtures were in two rows that divided the ceiling check details into thirds. The uneven number of fixtures was due to a lack of a fixture above the doorway which was situated in one corner of the room. During DL, the participants sat on floor mats placed approximately 10 m from the doorway. The door was closed and the lights turned off, such that the only illumination in the room

came from a 1-cm crack that ran under the door (0.91 m width). The participants sat quietly, and were kept awake by having them engaged in continual conversation with either other participants or a member of the research team. For RL and RLM, the subjects sat in the same area of the room with all of the lights lit. Like DL, during RL and RLM the participants were required to stay awake, and they were allowed to converse,

read or do schoolwork. The knee extension muscle endurance test for the differing exposures was performed in a seated position using a LifeFitness (Brunswick Corp., Lake Forest, IL, USA) knee-extension machine. Prior to the test, the full knee-extension range of motion was determined. The subjects would first TSA HDAC move the device unweighted until they could no longer extend their knees. Lines marking this position were then placed on both the stationary and moving parts of the machine, and subsequent lifts were not counted unless these marks were in alignment. To ensure that all lifts were performed at the same rate, a metronome set at 90 beats per minute was placed near the individual’s head. Each person was instructed to either raise or lower the weight with each beat (flexion and extension completed in approximately 2 s). All individuals had an initial practice with the metronome separate from the test to ensure the lifts could be made in synchrony with the

metronome. over For all tests, the resistance was set to the nearest (but not exceeding) 11.1 N (2.5 lb.) of 40% of the person’s body weight. A one-way ANOVA with repeated measures was used to compare the number of lifts for each condition. An additional one-way ANOVA with repeated measures was used to determine whether or not there was a difference between the three different days (i.e., the results were collapsed across days). Additionally, HR, MAP, and BG were analyzed using a 2-way (treatment vs. pre-post) ANOVA with repeated measures. Post-hoc ANOVA analysis involved, where appropriate, the use of Tukey’s protected t test. Statistical significance was accepted at an α level of p < 0.05 using SigmaStat version 2.0 (Jandel Scientific, San Rafael, Canada) statistical software.