If you've mastered Kingdom Come: Deliverance and you're looking for an additional challenge, or if you're just a fan of hardcore games in general, you might want to check out the latest 1.6 update. Besides the usual batch of bug fixes, the update has added a new Hardcore Mode where you will need to pay close attention to your health, stamina, energy, nourishment, location, and even permanent negative effects!
That last part might just be the most intriguing aspect of this new game mode as you will have to choose at least two negative perks before starting up your playthrough. These 'perks' can be things like nightmares that cause you to suffer from a short-term debuff after waking up, conditions like hemophilia that make you bleed a lot more profusely, or even something as benign as claustrophobia which makes your attacks clumsier while using the helmet visor. All of these are relatively small effects, but when it comes to spicing up an already difficulty game, I do believe they will do their job quite admirably!
As far as health regeneration is concerned, sleep is going to be your best bet in the Hardcore Mode. Food and healing potions will take quite a while to kick in, so if you're low on health it's probably not a good idea to rely on them alone. Speaking of which, in the Hardcore Mode you will only be alerted to the current state of your health and stamina levels through visual effects, so do make sure to pay attention before you find yourself sprawled on the floor.
The Hardcore Mode is also bringing with it a more realistic combat system, less generous traders, no fast travel, and the list goes on. You can find out more, as well as grab Kingdom Come: Deliverance at a 30% discount, over at Steam.