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Elevated levels
of norepinephrine and cortisol, key stress hormones, have been
observed in individuals with insomnia (Adam
et al., 1986). Metabolic rate has been used as an overall
indicator of stress activation, as the data in Figure 3.3.1 (Bonnet
and Arand, 1995) illustrate. This figure represents data for
overall metabolic rate (MR), and the MR during the sleep period
and during SWS. Within each set, 8 of 10 t-values for the paired
t-tests were significantly different.
| Figure
3.3.1 Metabolic Rate Comparison in Subjects With and
Without Psychophysiological-type Insomnia
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Adapted
from Bonnet MH, Arand DL. 24-hour metabolic rate in
insomniacs and matched normal sleepers. Sleep. 1995;
18:581-588.
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SNS
arousal generally elevates heart rate so one would suppose that
this indicator would be different in comparing subjects with and
without insomnia. From another study, Figures 3.3.2 (heart rate
across the night as averaged for each hour) and 3.3.3 (heart rate
change from baseline during a performance task) show heart rate
data comparing adults with psychophysiological-type insomnia to
people with no insomnia (Stepanski
et al., 1994).
| Figure
3.3.2: Heart Rate Across the Night as Averaged for Each
Hour
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Source:
Stepanski E, Glinn M, Zorick FJ, Roehrs T, Roth T.
Heart rate changes in chronic insomnia. Stress Medicine1994,
10:261-266. John Wiley and Sons, Limited, Reproduced
with permission.
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| Figure
3.3.3: Change in Heart Rate from Baseline During a Performance
Task
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Source:
Stepanski E, Glinn M, Zorick FJ, Roehrs T, Roth T.
Heart rate changes in chronic insomnia. Stress Medicine1994,
10:261-266. John Wiley and Sons, Limited, Reproduced
with permission.
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