One thing I know that cold, exercise, and loud noises all have in common is that the body responds to them by producing adrenaline. People are told by nutritionists to take compounds like tyrosine to make up for the essential nutrients (i.e. phenylalanine) that sustained adrenaline production uses up, if they work in an environment with frequent "shocks" of any of the above types.

I do wonder if actually being in such a phenylalanine-depleted state (which is then also a tyrosine-depleted, phenylethylamine-depleted, L-DOPA-depleted, dopamine-depleted, adrenaline-depleted, and norepinephrine-depleted state) has any long-term effects on the body, which might even be positive. Goodness knows it certainly makes you want to sleep for a week.

(Come to think of it, an interesting question would be whether people with phenylketonuria who grew up on a compensatory dietary-restriction regimen low in phenylalanine—thus causing such sustained deficiencies of all the above—have any physiological differences to people without phenylketonuria.)