Longest I could video record on iPhone without hurting the battery?

[Reminisce32]

I used my iPhone a few times to record video game matches that range from 30-60 minutes and remember the phone getting extremely hot. I was wondering if this damages the battery, as in shortens the battery life or the amount of time it can hold a charge, and what's the longest amount of time I should video tape to be safe?

Also, does video taping use as much battery as watching videos/streaming?

PS. I've been using the iPhone 5 and will be using the 6 Plus when it releases.

Thanks.