Supplementary Material for: Investigation of an Immediate Effect of Bright Light on Oxygen Consumption, Heart Rate, Cortisol, and α-Amylase in Seasonal Affective Disorder Subjects and Healthy Controls
<p><b><i>Background:</i></b> Body (fat) mass has been shown to decrease
following bright light treatment for overweight women, irrespective of
their seasonal (light) dependence. It is not known if this is due to an
(immediate) increase of metabolism. <b><i>Methods:</i></b> Ten women
with seasonal affective disorder (SAD) and 10 non-SAD women matched by
age, body mass index, and menopausal status participated in a laboratory
study in the morning, twice within 1-5 days. During one session, bright
light (4,300 lx) was presented for 30 min, and during the other
session, red light (250 lx “placebo”) was used. After an initial 15 min
of sitting quietly in an experimental chamber, 10-min measurements were
done before, at the end, and 15 min after light exposure; the subjects
remained seated for 80 min in total. The measurements included 5-min
oxyspirography (oxygen consumption, carbon dioxide emission, and heart
rate), saliva sampling for the estimation of cortisol and α-amylase
concentrations, and self-rating of mood, energy, and sleepiness. <b><i>Results:</i></b>
There was no light-specific effect on the measured variables, except
that sleepiness was reduced more with bright light than with red light
in the combined group. α-Amylase values were lower in the SAD patients
than in the non-SAD controls. <b><i>Conclusions:</i></b> Morning
artificial bright light, in comparison with dim red light, had no
immediate effect on metabolism and resting sympathetic tone, though
subjective sleepiness decreased more with bright light. SAD patients
have low salivary α-amylase levels, indicating lower sympathetic tone.</p
