Since some people have complained that they cannot think of a way to rationalise healing surges, here's my attempt at providing one possible in-game explanation of healing surges, built on two premises I've observed in 4E:
1) Healing surges are a fact of life in a 4E setting.
2) In 4E healing magic is taxing on the recipient.
I'm putting this forward in the hope that someone can take this half-formed idea and give it the polish I don't have time to apply at the moment.
Think of Healing surges as bursts of accelerated healing - the body's regenerative systems kicking into overdrive. PCs can even trigger this themselves voluntarily, either over a minute or more while resting, or in emergency during combat via the Second Wind ability (isn't adrenaline wonderful?), and other classes have learned how to inspire others to the point where a healing surge is triggered.
These healing bursts can even be used to overcome battle fatigue - cleaning out the toxins and replenishing the cells, allowing the body to return to full fighting focus when it was beginning to falter. (Healing when hit point loss is not high enough to represent actual wounds.)
But this regeneration taxes the body. It can only be done in short bursts, and each one puts more strain on the user's system. The body can only take so many before it needs to rest and recover. Once you reach that point, no form of healing - magical or otherwise, is going to be able to trigger a burst of healing. Such a person is on their last legs, and in need of rest soon.
1) Healing surges are a fact of life in a 4E setting.
2) In 4E healing magic is taxing on the recipient.
I'm putting this forward in the hope that someone can take this half-formed idea and give it the polish I don't have time to apply at the moment.
Think of Healing surges as bursts of accelerated healing - the body's regenerative systems kicking into overdrive. PCs can even trigger this themselves voluntarily, either over a minute or more while resting, or in emergency during combat via the Second Wind ability (isn't adrenaline wonderful?), and other classes have learned how to inspire others to the point where a healing surge is triggered.
These healing bursts can even be used to overcome battle fatigue - cleaning out the toxins and replenishing the cells, allowing the body to return to full fighting focus when it was beginning to falter. (Healing when hit point loss is not high enough to represent actual wounds.)
But this regeneration taxes the body. It can only be done in short bursts, and each one puts more strain on the user's system. The body can only take so many before it needs to rest and recover. Once you reach that point, no form of healing - magical or otherwise, is going to be able to trigger a burst of healing. Such a person is on their last legs, and in need of rest soon.