You should let your 2 year old cry it out until they become tired and fall asleep on their own.
Most times a 2 year old will tire of crying it out after 1 hour and 10 minutes to 2 hours and as long as the 2 year old has no health issue they are crying about then it's okay to just let them cry it out and they will eventually tire of crying and stop and fall asleep.
It is normal for a 2 year old to cry in their sleep as 2 year olds often cry in their sleep during sleep regression, or from bad dreams, nightmares or night terrors.
Other causes of 2 year olds crying in their sleep are sensory overload, developing imaginations or because the 2 year old's brain is transitioning between stages of sleep.
2 year old sleep regression involves the disruption in your 2 year old's sleep patterns and often involves increased wakings at night and resistance to taking naps and also having a longer time to settle down at bedtime.
2 year old sleep regression can also lead to increased clinginess, fussiness and even bedtime battles.
Skipping naps, resisting bedtime and sudden waking in the middle of the night and early morning rise time are common signs of sleep regression in 2 year olds and toddlers.
Too much sleep can also make a toddler cranky.
Although lack of sleep or not enough sleep is a more common cause of a toddler being cranky, it's also possible for toddlers to become cranky and fussy even when they get too much sleep.
Too much sleep in toddlers can also lead to and cause mood disturbances and make it harder for the toddler to fall asleep at night.
Oversleeping can disrupt the production of serotonin, which is a neurotransmitter that regulates mood and it can occur in toddlers, children, teens and even adults that get too much sleep.
The reason why toddlers cry when they are sleepy is a result of over stimulation, separation or sleep regression.
Over tiredness in toddlers is when the toddler has slept less than the 11 to 14 hours of sleep that is recommended which can trigger sudden crying in toddlers.
And developmental milestones and night terrors can also lead to crying in toddlers at bedtime.
Sensory overload can also lead to crying in toddlers when they are sleepy.
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.