لخّصلي

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.

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.