Xerox CEO Ursula Burns rises at 5:15 a.m. to email and work out.

Burns uses early morning hours to get caught up on emails, getting up at 5:15 a.m. and sometimes working until midnight, according to Yahoo Finance.

She also uses the time to fit in a workout, according to Laura Vanderkam's "What The Most Successful People Do Before Breakfast." Burns schedules an hour of personal training at 6 a.m. twice a week.