لخّصلي

2.Subjects' average self-reported habitual caffeine consumption, calculated using publicly available norms for caffeine dose by type of caffeinated drink or chocolate [17], was 114 +- 98 mg (mean +- SD) per day.They were free of traces of alcohol, tobacco, and drugs (except for oral contraceptives) as assessed by blood analysis, urine cotinine test, urine drug test, history, and questionnaires.The study was reviewed and approved by the Institutional Review Board (IRB) of Washington State University, and conformed with the Code of Ethics of the World Medical Association (Declaration of Helsinki).Subjects had no history of a moderate to severe brain injury, learning disability, or psychiatric illnesses, as assessed by history and questionnaires.For the week prior to the laboratory experiment, subjects were also instructed to refrain from caffeine and alcohol consumption, and to avoid drugs including tobacco.Subjects had no sleep disorders, as verified by history, questionnaires, actigraphy, and baseline polysomnography.During the week prior to the laboratory experiment, subjects were instructed to maintain their habitual sleep schedules and to avoid napping.Compliance was verified with wrist actigraphy (Actiwatch-2; Respironics, Bend, OR).Methods 2.1.

2. Methods
   2.1. Subjects
   Twelve healthy young adults (mean age ± SD: 27.4 ± 6.9 years,
   range: 19–39 years; mean BMI ± SD: 24.2 ± 5.2; 10 Caucasian and 2
   Hispanic; 6 women) completed the study. Subjects were physically and
   psychologically healthy as assessed by history, questionnaires, and a
   physical examination by a physician. Subjects had no sleep disorders, as
   verified by history, questionnaires, actigraphy, and baseline
   polysomnography. They were free of traces of alcohol, tobacco, and
   drugs (except for oral contraceptives) as assessed by blood analysis,
   urine cotinine test, urine drug test, history, and questionnaires. They
   reported being free of tobacco use for at least three years. Subjects had
   no history of a moderate to severe brain injury, learning disability, or
   psychiatric illnesses, as assessed by history and questionnaires. They
   were not exposed to shift work within 3 months of entering the study
   and did not travel across time-zones within 1 month of entering the
   study. All subjects reported to be good sleepers, habitually sleeping
   between 6 and 10 h daily with regular bedtimes and habitually waking
   between 06:00 and 09:00.
   Subjects' average self-reported habitual caffeine consumption, calculated using publicly available norms for caffeine dose by type of
   caffeinated drink or chocolate [17], was 114 ± 98 mg (mean ± SD)
   per day. One subject reported habitually not consuming any caffeine.
   Subjects reporting more than an average of 400 mg of caffeine intake
   per day were not allowed to participate in the study.
   During the week prior to the laboratory experiment, subjects were
   instructed to maintain their habitual sleep schedules and to avoid
   napping. Compliance was verified with wrist actigraphy (Actiwatch-2;
   Respironics, Bend, OR). Additionally, subjects filled out a sleep/wake
   diary, and reported their bedtimes and rising times on a time-stamped
   voice recorder. For the week prior to the laboratory experiment, subjects were also instructed to refrain from caffeine and alcohol consumption, and to avoid drugs including tobacco. Compliance was verified with urine and breathalyzer tests on the first day in the laboratory.
   The study took place in the controlled laboratory environment of
   the Sleep and Performance Research Center at Washington State
   University Spokane. The study was reviewed and approved by the
   Institutional Review Board (IRB) of Washington State University, and
   conformed with the Code of Ethics of the World Medical Association
   (Declaration of Helsinki). All subjects gave written, informed consent,
   and were financially compensated for their time.