As an action, a character can use a healing surge and spend up to half his or her Hit Dice (min. 1). For each Hit Die spent in this way, the player rolls the die and adds their Constitution modifier. The character regains hit points equal to half the total.

 

A character who uses a healing surge can't do so again until he or she finishes a short or long rest.

You call upon your faith in a time of great need. Spend one Hit Die to use your Channel Divinity.

 

A character who uses a Divine Surge can't do so again until he or she finishes a long rest.

As an action, you center yourself and plumb the depths of your mind to recall some of your magical ability. Spend one or more Hit Dice of your Spellcasting class to regain a spell slot. You spend Hit Dice equal to a level of a spell slot you can use, and recover that slot. If you use Spell Points, you instead gain the Spell Point equivalent, but cannot exceed your maximum amount of Spell points. You then gain 1 level of Exhaustion

e.g.  A 5th Level Wizard may choose to spend 3 Hit dice to recover a third-level spell slot or the equivalent Spell Points.

 

When a player takes the Attack action, they may choose to spend 1 of his or her Hit Dice to fuel this ability. They roll their hit die and add the result to one of their attack roll, and must choose to do so before the roll. This represents a creature burning through a portion of their remaining strength to deal more devastating damage. On a successful attack a creature takes additional damage equal to the result on the hit die.

 

A character who uses a power surge can't do so again until he or she finishes a long rest.