Tiredness shows the breathlessness' status of your unit. It increases with each action such as moving, attacking, bombing, caring or building
If the unit is too tired, it may join the opposite army during the next attack or desert if it is bombed (except the commander; see also Deserters).
Tiredness can also prevent from carrying out some actions.
To make it decrease, it is necessary to "rest" the unit. It costs 10 AP.
Tiredness influences the precision. The more the unit is tired, the more the precision drops.