Phase 1: Physical Conditioning 7 weeks

Phase 1: Physical Conditioning (7 weeks)

The first phase of BUD/S assesses SEAL candidates in physical conditioning, water competency, teamwork and mental tenacity. Physical conditioning utilizes running, swimming and calisthenics and grows harder and harder as the weeks progress. Candidates will participate in weekly four mile timed runs in boots and timed obstacle courses, swim distances up to two miles wearing fins in the ocean and learn small boat seamanship.

The first two weeks of basic conditioning prepare candidates for the third week, also known as "Hell Week." During Hell Week, candidates participate in five and a half days of continuous training. Each candidate sleeps at most four hours during the entire week, runs more than 200 miles, and does physical training for more than 20 hours per day. The remaining four weeks involve the acquisition of various methods of conducting hydrographic surveys and creating a hydrographic 

Because of its particularly challenging requirements, many candidates begin questioning their decision to come to BUD/S during First Phase, with a significant number deciding to Drop on Request (DOR). The tradition of DOR consists of dropping one's helmet liner next to a pole with a brass ship’s bell attached to it and ringing the bell three times.^[10][13]

It has been reported that all candidates receive two medical examinations within 24 hours after Hell Week.