Starfield Skills -> Physical Skills
Fitness is a skill in Starfield located in the Physical skill tree that grants the player more Oxygen while making Sprint and Power Attacks more efficient.
Fitness Skill Description
In space, the greatest commodity is oxygen, and the increased lung capacity gained by a regular physical fitness regimen is essential to survival.
Fitness Skill Ranks
You have 10% more oxygen available.
You have 20% more oxygen available.
You have 30% more oxygen available.
Sprinting and power attacks now use significantly less oxygen.