The reason why toddlers go crazy when tired is because the toddlers body releases stress hormones such as adrenaline and cortisol, which gives the toddler a temporary boost or burst of energy.
The second wind which it's also known as can also be mistaken for an energized state even though the toddler is actually tired or overtired.
The increased energy in the toddler when overtired is a way to try and keep the toddler awake and active and prevent them from falling asleep.
When toddlers are overtired they will act fussy and be irritable, clingy, clumsy and be difficult to soothe or settle down.
Other signs of a toddler being tired or overtired are rubbing their eyes, yawning, a loss of interest in activities and they may try to fight falling asleep.
A toddler that is overtired may start falling asleep when at the table and eating or sitting on the couch, floor etc and they may try to wake up and keep their eyes open but may eventually just fall asleep.
Overtired toddlers may feel dizzy and be prone to falls and tumbles and sleep on short rides.
Toddlers that are tired or overtired often become more easily upset and cry more frequently and become harder to soothe.
An overtired toddler also often becomes more attached to their parents and resit being separated and the toddler may even be easily annoyed, have shorter temperas and be harder to please.
Over tiredness in toddlers can also lead to and exacerbate tantrums and make the tantrums in toddlers more intense and frequent.
Toddlers that are tired or overtired often lose interest in playing, lose interest in toys and activities that they normally enjoy otherwise.
Demands for attention and difficulty in concentrating also often occur in overtired toddlers.
Overtired toddlers often become more demanding for attention and require constant reassurance.
Other signs of toddlers being overtired are pulling at their ears, yawning, heavy eyelids, glazed over look and they may fall asleep easily during the day or when in a vehicle.
Grizzling or crying such as making low, whiny cries are a sign of a toddler being tired or experience discomfort and fussiness with food is also often a sign of a toddler being overtired and they may refuse to eat.