If you want to train their hearts, to train their body to handle
oxygen deprivation, then I suggest that short sharp busrts of
speed, followed by periods of rest is the way to go (interval trg).
Professional sprtsmen do that, why not the army? Singing does not
really tax their lungs and there is no real way of monitoring who
is not actually singing. Again, If you can sing, you are not
training anything other than singing.
So whatever advantages to be gained by singing, can be gained
through other more effective and proven methods.
To move on with why NOT singing - Singing on route marches is not
training as you fight. I have been involved in a brigade exercise
and a couple of battalion exercises before, and as far as I know,
when marching to attack the objective, nobody advertises their
presence by singing. In fact, during those marches, stealth is the
key. That is why we are told to tape down everything, not to use
torches, not to talk, not to mark routes too obviously and to avoid
attacking in broad day light.
Singing helps lift morale. mmm...Maybe or probably. But you do not
have that luxury when on exercise or on Ops so why not learn to
live w/o that luxury?
Singing builds camaraderie - Yes, I agree. Then make them sing when
marching to the cook house or something.