That exercise is effective treatment for relieving depression has become a recent shibboleth. And it's proponents will not take this lying down.
When it comes to neuroses in particular and mental illness in general, many things recommended have not been conclusively established as particularly efficacious.
Something to do with the psychosomatic or placebo effect of intervention. Subjectivity is usually king and has been allowed to bleed senselessly (or been used) to establish an efficacy not borne out in the cold light of day.
So, if people say repeatedly banging their heads against a brick wall, makes them feel better then that is often taken as evidence of positive potency. Well, you can't argue with people insisting it is valuable, because it helped them, can you? Too often, personal advocacy borne of desperation, helps shield methods from rigourous scrutiny.
The amusing thing is how this got started. Exercise is not a particularly promising way of treating depression. One of the latter's most notorious symptoms is a compromise or even loss of one's instinct and desire to move.
This is not, as is easy to assume, because one has become lazy due a nervous system set on standby. It's more down the exhaustion of a permanently overwrought, therefore overworked system. Heavy emotions such as panic, anxiety, fear, trauma, loss, grief and so on tax your central nervous system especially, meaning less available energy.
It is a shock to learn the very thing you think you think is the problem, doing too little is actually the product of nervous overload. And that what you need to do is make your mere existence less like hard work and more like neutral.
Whether it's specific; bringing resolution to as many unresolved traumas and dramas of the past as you can manage. And/or general i.e. re-training our normal state to one which is less nerve wracked. Learning to get less het up about things.
Releasing more energy from your stores isn't without meaning. This is probably along the lines of craving calorie dense foods (appetite) or increased energy demand (hunger) when one's mood is lowered.
Energy is clearly a central fact of your body's attempts to keep your head above water.
There is a possibility that for some, mindless repetitive motion revives not just your instincts to move, but some aspect of your nervous function. It can help to dispel nervous energy that may otherwise be part of tiring out your system. Moving can mean a break from endless negative cycles of thought.
It should be tested more. Not just exercise. For all we know, simple physical movements may involve parts of the brain in ways that break up negative cycles of thought.
Trouble is, for many, by the time you are depressed, your body, i.e. your muscles, bones even have already collected so much stress which only at that point translates into depression. If you have this response, it can make exercising deeply unpleasant, if not shattering experience.
It's possible that if it were viewed more objectively, exercise or physical movements could assist in diagnosis as well treatment even. If exercise/movement feels alright or good, it could be a different, less entrenched depression. This could be down to more recent or current thinking/circumstances.
If exercise is more like an invasive assault, it could that your depression is more long term and more to do with having to be out of touch with your feelings over a longer period.
I'm speculating. My point is we'd do well to examine this in terms of movement, rather than the fitness mindset which clouds the issue.
It would be interesting to test aerobic type against healing based movement regimes such as yoga, tai chi, walking meditation and so forth. I daresay the latter might have a better effect on those who have to use their bodies a lot, i.e. low socio economic groups. The favouring of aerobic type motion speaks to the more office based.
That may even be what's making some of them down in the mouth.
I also have my suspicions about the instigator of this enthusiasm for exercise;
Melanie Chalder, of the University of Bristol's School of Social and Community Medicine, said: "Numerous studies have reported the positive effects of physical activity for people suffering with depression but our intervention was not an effective strategy for reducing symptoms. "However, it is important to note that increased physical activity is beneficial for people with other medical conditions such as obesity, diabetes and cardiovascular disease and, of course, these conditions can affect people with depression."Well, there you are. It's one thing to be depressed. It's quite another to lose status. Which would be depressing in itself, right?