The only way to heal is by crafting or foraging First Aid Kits. You can also take Health hits and lose HP when leviathans and other animals attack.You may also eat Fevered Peppers, which raise your body temperature, or stand near Thermal Lilies on Delta Island. Above ground, you'll need to find shelter, likes the caves in the Glacial Basin. You also get cold when you stay still too long underwater. If your PDA warns of hypothermia, that means you're getting too cold.You can also eat Fevered Peppers or drink any Disinfected Water you find in storage crates at various locations, like Phi Robotics Lab, Delta Station and others. If your PDA recommends fluid intake, you can use a Bladderfish to create water with your Fabricaator.This includes Fevered Peppers, which grow in the Glacial Bay biome, and the underwater Bull Eye Shroom which grows near your Drop Pod. However, this will dehydrate you, so we recommend cooking the fish in your Fabricator or consuming fruit or edible fungi. Some common edible fish are Bladderfish, Arctic Peeper and Hoopfish. If your PDA recommends calorie intake, you can consume raw fish gathered nearby.You can also enter your Seabase if it has power. These have oxygen production as long as you have power to them. If your oxygen is low, you can swim to the surface or pilot the Seatruck or Prawn Suit.When these levels get low your PDA will warn you what the problem is, whether it's recommending fluid or calorie intake or warning of hypothermia. Green is for Oxygen level, red is for health, yellow is for food, blue is for water and the teal on the far right is for body temperature. The circles on your screen will indicate the level of each.