“The passage of time itself is distorted: a couple of long sessions in cold water, hard winds, and big waves can make two days seem like two weeks. Mark has a theory: that the sense-deprivation involved in cold-water surfing can throw the body into a state resembling insulin shock, which causes a similar distortion of time. Mark also has a rule: “For every hour you surf in San Francisco in winter, add one hour of sleep.” The rule has an exception: for Dead Man’s, which has an especially ferocious current, Mark says, “Add two.””
— Ocean Beach. The jewel of San Francisco, hiding in plain sight.