E S E A R C H
Thermal Therapy Benefits Depressed Patients
Repeated thermal therapy may be useful for
mildly depressed patients with appetite loss and subjective complaints,
according to a recent study.
“Repeated Thermal Therapy Diminishes
Appetite Loss and Subjective Complaints in Mildly Depressed Patients”
was conducted by staff at the Psychosomatic Medicine, Respiratory
and Stress Care Center at Kagoshima University Hospital, Japan.
Twenty-eight mildly depressed inpatients
with general fatigue, appetite loss, and somatic and mental complaints
were assigned randomly to a thermal-therapy group or a nonthermal-therapy
group. Patients in the thermal- therapy group were treated with
60 C far-infrared dry sauna for 15 minutes and were then kept at
bed rest for 30 minutes once a day, five days a week, for a total
of 20 sessions in four weeks.
All patients were admitted to the hospital
and fed identical meals totaling 2,000 calories a day. They were
weighed before and after each sauna. Weight loss after thermal therapy
was regarded as perspiration, and this water loss was replenished
to prevent dehydration.
A far-infrared ray (> 4 _m) dry sauna
system was used for thermal therapy. Each patient in the thermal-therapy
group, wearing a gown and underwear, was placed in a supine position
on a bed for the 15-minute sauna session, then moved into a room
maintained at 28 C (82.4 F) and wrapped in a blanket for the 30-minute
bed rest. Patients in the nonthermal-therapy group were placed in
a supine position on a bed in a temperature-controlled (24 C; 75.2
F) room for 45 minutes.
Somatic complaints, hunger and relaxation
scores significantly improved, and mental-complaint scores slightly
improved in the thermal-therapy group compared with the nonthermal-therapy
group. Furthermore, plasma ghrelin concentrations and daily caloric
intake in the thermal-therapy group increased significantly compared
with the nonthermal-therapy group. (Ghrelin is a growth hormone-releasing
peptide that stimulates food intake and body weight gain.) Norepinephrine
levels were slightly lowered by thermal therapy.
The use of far-infrared rays in sauna bathing
is known to increase skin temperature, blood flow and core body
temperature. Increased blood temperature excites the warm neurons
of the heat regulatory center in the hypothalamus and inhibits cold
neurons. In addition, these warm neurons are projected to the neurons
of the sympathetic/ parasympathetic centers in the hypothalamus,
influencing the autonomic nervous system.
The use of elevated temperatures and repeated
sauna/ postsauna warming may inhibit the sympathetic nerves (the
fight or flight response), making the parasympathetic nerves (the
resting and digesting system) predominant. Mild warming of the whole
body has been known to exhibit sedative effects through sensory
nerve endings, which would suggest that repeated thermal therapy
might decrease the frequency of somatic and mental complaints by
exhibiting psychosomatic relaxation and sedative effects.
In addition, an increase in core body and
dermal temperatures enhances metabolism and increases energy consumption.
This may be how repeated thermal therapy induces hunger via elevated
ghrelin and epinephrine.