The health and fitness industry has been aware of the role of exercise as an ‘anti-depressant’ for a while. But only now are people beginning to believe that 30 minutes in the gym works as well, if not better than, most medications – and without the side effects.

In simple terms, there’s a chemical cocktail that keeps our mood in balance and when that cocktail gets out of whack the ‘black dog’ is often not far away. There are a number of factors at play here, but let’s keep it simple: In the blue corner, we have the stress hormone cortisol; in the red corner, we have a bunch of happy hormones and proteins like serotonin, dopamine and Brain Derived Neurotrophic Factor (BDNF).

Designed to help us manage fight and flight situations, sabre-toothed tigers et. al., cortisol is fine in small doses but when we are chronically stressed it has a nasty habit of reducing the levels of the happy hormones – with predictable consequences. Cortisol 1 – Happy Hormones 0.

One way of dealing with the anxiety and depression that often ensues from elevated cortisol and reduced happy hormone levels is to take anti-depressants – and, of course, they have a role to play – but an equally effective and arguably less addictive approach is to exercise regularly. Two reasons: Exercise reduces cortisol levels and increases serotonin, dopamine and BDNF levels. Double whammy. Cortisol 1 – Happy Hormones 2.

You can see where I’m going with this but just for the sake of clarity, no-one is saying you should bin all your pills and buy an exercise bike; what we are saying is that if you haven’t considered exercise as part of your mood management plan now might be a good time to do so.