Is the heat haze effect just that or some kind of sickness?

[linfosoma 38]

As the title suggest, from time to time I see a sort of heat haze effect on the screen (mostly on far away objects) and I've been wondering if it's indeed caused by the heat or if it's some sort of status indicator, like the screen going monochrome when you are low on blood. 

[spinager 152]

hmm, hadnt thought of it that way. I figure its some kind of heat effect.

[Pvt Dolin 137]

I believe that it's displayed from having certain video settings.

But I could be wrong. It might be a status indicator if you're high on hunger/thirst/sickness.

I'll check on it the next time I play today.

[linfosoma 38]

hmm, hadnt thought of it that way. I figure its some kind of heat effect.

 

Yeah, I thought so too, but I could swear I've seen it during night time too, hence my doubt. 

[Merrick362 (DayZ) 263]

It only happens when you run for a long time. I'mI'm pretty sure it's just a fatigue indicator.