Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 3
It is not anything physical but a vital depression (in some part of the vital, not the whole) that prevents the body from recovering its elasticity. There was some part of the vital that was resisting a radical change and even, unknown to your mind, trying to go 
on as it was under cover of the change in the rest of your being. This has now, owing to this last affair, received a blow and got depressed and, when the vital is depressed like that, it affects the body. You say rightly that it is part of a change or turn that is taking place. But these effects of inertia and weakness need not continue; as soon as this vital part acquiesces gladly in the turn or change, the elasticity and energy will return.