When you have depression, there are few things more frustrating than someone telling you to 'have a cup of tea' or to 'have a hot bath' so that everything will feel better. Depression is a mental illness and it's far more complex than that.
But according to a scientific study conducted last year, the latter tidbit of advice about having a bath could actually have some practical impact.
A group of researchers at the University of Freiburg in Germany took a small sample of participants with depression (45 in total), and split them into two groups. The first group was instructed to take a hot bath every afternoon at a temperature of 40ºC for up to 30 minutes at a time, while the second group were required to undertake 40 to 45 minutes of aerobic exercise twice a week.
After eight weeks, participants' states of mind were measured using a typical depression scale. The group that had the daily hot baths were found to have scored six points lower (indicating lesser levels of depression) than prior to the experiment, while the group that had been doing regular exercise only scored an average of three points lower. The findings indicated you could hypothesise that regular hot baths were more effective than exercise when it came to improving the symptoms of depression.
The scientific theory behind why warm baths could have such an impact on people with depression is all to do with the body's circadian rhythm. The circadian rhythm is essentially a 24-hour internal clock that tells us when to sleep, and impacts the behaviour and biochemistry of our bodies using temperature.
Depressed people tend to have a flatter circadian rhythm (which is why insomnia can often be a symptom of depression), but by increasing the core body temperature of a person with depression, in theory this could help to strengthen their circadian rhythm and improve depression symptoms.
Of course, with the study size being so small, the results must be taken with a pinch of salt. Normally it would require a far larger sample size to make sweeping statements about what activities can and can't aid people with depression. But having said that, a warm bath isn't exactly unpleasant - so perhaps it couldn't hurt to try.