Hardcore Mode

 is an optional gameplay mode in Fallout: New Vegas that increases the challenge of the game. In this mode stimpaks heal over time, Rad-Away removes radiation over time, ammunition has weight, dehydration is a constant concern, you must have regular sleep cycles, food doesn't heal health, instead you must eat to survive, and to heal limbs you must use a medical brace or a doctors bag.

For beating the whole game from start to finish in hardcore mode, the players get the Hardcore achievement/trophy.

You can turn Hardcore mode off at any time, but you cannot turn it back on. The game continues to track your primary needs, and turning it back on after completely depleting your primary needs would kill you instantly.