It's all in the mind it is true :
But our physiology is real too - our energy input is real - no input -no energy = we will probably become tired and miserable and will have to resort to outside help for stimulation - tea, coffee, alcohol, drugs, sugar, nicotine. The very things that are accepted as being a normal part of many people's lives.
BUT - Energy depletion comes from many sources, not least of which is emotionality - followed closely behind by compulsive thinking (or the other way round) - worrying too much - working too much- not enough (proper) relaxation - not eating appropriately - and much more besides.
So if you feel out of sorts, before you consult the oracle or the astrological alignments of Uranus, try checking off the list above e.g, tired, worried, hungry etc.
Depletion of energy is one thing - where do we get energy from and how do we get it is quite another.
Personally I think Pranayama is 'the' source divine of energy and it has saved my soul on more than several occasions.
It kind of goes like this for me:
Something happens and I react (tch, tch) - I think too much about what happened - I then get emotional (but I will never admit it) - I get tired - then I get even more worried - and so on down into a hole of my own digging.
It was at this point, and more often that not before this point, in the past, that I would reach for the smoke, the drink, the whatever, whatever, to make me feel better.
Not having that option now it is a little more difficult, (in a way), but a million times more rewarding to deal with things head on.
So now, once I reach the bottom of this hole, (and I do think it is good sometimes to go to the bottom of it) and sometimes before, I usually 'act', and do something about it.
In other words, I get out the yoga mat and do some asana - pranayama - etc.
I (usually) feel much better as a result, dependent of course on the level of insanity I have reached prior to this point!
After the event, i.e, when I finally become more reasonable again, if if I rationally ask myself what has changed, I can only say that in all honesty that I have moved my body, (asana), and I have breathed in a more conscious way, (pranayama).
The combination of these two actions has changed something and enabled me to enter into a more relaxed and detached state of mind.
Now that this state (of consciousness) has been achieved, I can look a little more closely at 'what' is was/is that is/was upsetting me in the first place.
This (ongoing) ability to stay focused and look within is called, Dharana, (concentration).
Which of course (?) leads to meditation, in other words, the ability to sit still in a calm way and look deeply within at our conditioning. And in so doing becoming more aware of myself/ourselves, and what we are doing, and perhaps why we are doing what we are doing, and even more important,
Does it matter ?
:))
"Get out of that without moving" Tommy Cooper.