February 12, 2024: People with depression may have higher body temperatures and lowering the heat is likely to be beneficial to them, according to researchers from the University of California San Francisco.
A university team analysed data from 20,880 individuals collected over seven months from 106 countries and found that the connection was worth investigating.
Researchers analysed data from international participants who wore a device that measured body temperature and also self-reported their body temperatures and depression symptoms daily.
Novel treatment option
The study began in early 2020.
“The results showed that with each increasing level of depression symptom severity, participants had higher body temperatures,” according to a statement from the researchers.
“The body temperature data also showed a trend toward higher depression scores in people whose temperatures had less fluctuation throughout 24 hours, but this finding didn’t reach significance.”
The study’s findings shed light on how a novel depression treatment method might work, said Ashley Mason, PhD, the study’s lead author and associate professor of psychiatry at UCSF Weill Institute for Neurosciences.
A small body of existing, causal studies has found that using hot tubs or saunas can reduce depression, possibly by triggering the body to self-cool, for example, through sweating.
“Ironically, heating people up actually can lead to rebound body temperature lowering that lasts longer than simply cooling people down directly, as through an ice bath,” said Mason, who is also a clinical psychologist at the UCSF Osher Center for Integrative Health.
“What if we can track the body temperature of people with depression to time heat-based treatments well?”
No single biological or behavioural abnormality characterises individuals with massive depression disorder.
The identification of an abnormality associated with the disease may open the door to identifying a relatively “biologically homogeneous subgroup” that demonstrates a larger treatment response to interventions that target the specific abnormality, the authors wrote in Scientific Reports.
Distal body temperature
One physiologic characteristic that may hold potential as a therapeutic target is thermoregulatory dysregulation which is among the most widely reported circadian biological abnormalities in affective disorders, including the massive depression disorder.
This has been observed in the form of elevated body temperature, particularly at night, when thermoregulatory cooling responses are critical for sleep onset and quality.
Such temperature elevations have also been reported during the day. In these analyses, higher levels of depressive symptoms were associated with higher body temperatures during time awake.
The researchers found that distal body temperatures collected by the wearable sensor device during sleep were fairly similar across depression categories and were higher than awake distal body temperatures.
This resulted in smaller asleep–awake distal body temperature differences with increasing depressive symptom severity, according to the researchers.
Under controlled laboratory conditions when people are kept awake, the circadian rhythm in distal skin temperature — in the feet, hands, and ears — shows a strong amplitude that is out of phase with the rhythm in core temperature, which is low during the day and high at night.
“To our knowledge, this is the largest study to date to examine the association between body temperature – assessed using both self-report methods and wearable sensors – and depressive symptoms in a geographically broad sample,” added Mason.
Though depression is biologically, behaviorally, and psychologically heterogeneous, these findings suggest that body temperature may be a candidate biological marker of depression for some individuals with depressive symptoms.
“Given the climbing rates of depression in the US, we’re excited by the possibilities of a new avenue for treatment.”
The study doesn’t conclude whether depression raises body temperature or a higher temperature causes depression.
It’s also unknown whether the higher body temperature observed in people with depression reflects decreased ability to self-cool, increased generation of heat from metabolic processes or a combination of both.
Treatments that target elevated body temperature in individuals with both elevated body temperature and depression may warrant further evaluation, the authors wrote.