In The Long Dark, pressing F (on PC) brings up the status page:
This includes the Fatigue gauge:
Sometimes there's a yellow exclamation mark on top of it, and sometimes part of the meter is red – what do these indicate?
What do the symbols on the Fatigue gauge mean
the-long-dark
Related Solutions
Hit Tab to open the survival panel. One of the options is "Forage Wood":
If you're outdoors, you get three options: Tinder, Softwood (i.e. Cedar firewood) or Hardwood (i.e. Fir firewood).
If you're indoors, you get two options: Tinder or Reclaimed wood.
You don't appear to need any tools to forage for wood, and I haven't noticed any furniture disappearing when I do it indoors.
The game features four different gauges, for warmth, tiredness, nutrition and hydratation. When either of those gauges is empty, an icon (which is also depicted above the leftmost extremity of the relevant gauge - that's how I found that answer) is displayed in the bottom-left corner of the screen, along with a percentage. As long as the character suffers deprivation from the relevant need, that percentage decreases with time.
At ten percent, the game starts reflecting the effects of the deprivation, and the percentage turns red. As the percentage gets lower, the displayed effects worsen. If this percentage reaches zero, the character dies.
The significance of this specific icon is that the character has reached a frozen state, due to his (or her) low body temperature.
Best Answer
It seems the exclamation mark appears if you have been starving for a long amount of time. It means your stamina will drop faster than normal.
The red part of the meter represents a reduced maximum, it has the same cause but appears later and slowly grows.
Eating doesn't immediately fix this. Eating and then sleeping cures it.