Demystifying Depression/Feeling Good vs Actual Improvement
Feeling Good vs. Actual Improvement edit
Sports alone can lift up a depression, says one of the most common pieces of advice about the illness. Unfortunately, this statement is grossly incomplete, often tragically so. If you have properly understood the roles played by adrenaline and cortisol (take a look again at the section on The Stress System to refresh your memory), you already have a glimpse of why this is such misleading advice. Exercise can indeed momentarily lift up the subjective feeling of a depressed person, but that is all caused by adrenaline. It is therefore critical to make the distinction between the momentary mood improvement caused by exercise (which is undisputed), and whether it translates into an actual improvement of the underlying depression.
Please refer back to The Stress System. There I have speculated on recent findings which indicate that a process known as neurogenesis ("neuron birth") is implicated in recovery from depression. This process takes about three weeks to occur*, which also happens to be the average time required for antidepressants to have an effect. This coincidence has led some to hypothesise that antidepressants work by stimulating neurogenesis . The point of this digression is to emphasise that anything which has a positive effect on recovery from depression is likely to require at least three weeks to work and will often take longer to be noticeable. One should therefore be a bit suspicious of any cure which seems to work instantly, as is the case of exercise.
Now the question is: does exercise also have a long-term positive effect on depression, or is it all a short-term illusion?