Immelt gets up at 5:30 in the morning every day for a cardio workout, during which he reads the papers and watches CNBC, he told Fortune. He claims to have worked 100 hour weeks for 24 straight years.  

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

She also uses the time to stay in shape, scheduling an hour of personal training at 6:00 A.M. twice a week, according to Laura Vanderkam's "What The Most Successful People Do Before Breakfast."

Marchionne splits his time between Turin, Italy and Auburn Hills, Mich.

When in the U.S., he gets up at 3:30 in the morning to deal with the European side and still have time for everything else, he told "60 Minutes."

"You and I have lived among workaholics in our day. I have never seen anything like Sergio," Obama "car czar" Steve Rattner said on the show. "When it was a holiday in Italy he'd come to America to work. When it's a holiday in America he goes to Italy to work. Saturdays and Sundays were just workdays to him and for his whole team. And anybody who signed up with Sergio signed up for the program.

Bloomberg TV

Running the world's largest bond fund in the world from California pretty much guarantees early mornings. According to Fortune, Gross wakes up at 4:30 in the morning to check out the markets and gets into the office by 6. 

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Dorsey described his morning routine to New York Magazine, revealing that he wakes up at 5:30 to meditate and go for a six-mile jog.

He kept up that routine during a period where he shuttled back and forth between Square and Twitter, spending around 8 hours a day at both companies. 

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In an interview with Business Insider's Aly Weisman, Branson revealed that he wakes up at around 5:45 in the morning, even when staying at his private island, leaving the curtains drawn so the sun gets him up. 

He does his best to use those early hours to exercise before an early breakfast and getting to work. 

YouTube

Nooyi wakes up as early as 4:00 A.M., telling Fortune that "They say sleep is a gift that God gives you ....that's one gift I was never given."

In a speakers series at Pepsi, she revealed that she's at work every day by no later than 7.

GM website

Akerson told the AP he will "rarely sleep past 4:30 or 5," waking up so he can talk to GM Asia before it gets too late. He calls it the best job he's ever had: "It's complex and interesting and exciting."

But the stress gets to him too, leading to "a lot of sleepless nights."

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Cush described his morning routine to the AP: Wakes up at 4:15 a.m., sends emails, calls business associates on the East Coast, and that's before listening to Dallas sports radio, reading the paper and hitting the bike at the gym.

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Cook is known for getting up and sending out company emails at 4:30 in the morning, according to Gawker's Ryan Tate. By 5 AM he can be found in the gym. And he works late too, priding himself on being the first in the office and the last out.

Business Insider

Iger told the New York Times he gets up at 4:30 every morning. He takes the quiet time to do a number of things, claiming to read the papers, exercise, listen to music, look at email, and watch TV all at once. Even though it's quiet time, he's "already multitasking."

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Simon wakes up 5 a.m. and immediately starts working, going through emails and calling operations in Europe and Asia. He also prays, walks the dog and exercises before his kids wake up, often scheduling a breakfast meeting before arriving at his Long Island office by 9 a.m.

"I have always been an early riser. As you can see, I accomplish a lot in four hours and now feel pumped for the remainder of the day," Simon told National Post, also saying he works 75 to 100 hours a week running the company behind brands like Rice Dreams and Celestial Seasonings.

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Now headed to the board of Eutelsat Communications, the former head of Peugeot was said to catch the 4 a.m. train from Dijon to Paris and would finish up a briefing paper within minutes of arriving to his office at 7 a.m. According to The Guardian, Folz also had his Renault Espace converted into an office so he could work while commuting.

Robert Holmgren

"I get up at 4:30 every morning to walk my three dogs and work out. Around 5:45 a.m. I make coffee for myself and my wife, using an 8-cup Bodum French press," Schultz told Bloomberg Businessweek. 

The coffee magnate still gets to the office by 6 a.m., according to Portfolio.com.

Crains

The youngest CEO in the NBA told SellingPower that he gets up at 3:30 in the morning in order to get to the office by 4:30. From there, he works out and sends motivational emails to his team.

He takes it easy on the weekends, arriving at the office by 7 a.m. instead.

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The founder of Oxygen is awake by 6 a.m. and out of the house a half hour later. If you get up early enough she might even take you under her wing, she tells Yahoo! Finance:

"Once or twice a week, I go for a walk in Central Park with a young person seeking my advice. This is my way of helping bring along the next generation. And if someone is up early in the morning then they are serious about life. I can't take time at the office to do this, but doing it in the morning allows me to get exercise and stay connected with young people at the same time."

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Ouimet likes to get to the office early, waking up at 5:30 in order to get out of the house by 6 a.m.

“I’ve always been anxious to get to work: game time," he told Yahoo Finance.

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After waking up at 4:30 a.m., Warrior spends an hour on email, reads the news, works out, and gets her son ready for school. She is still in the office by 8:30 at the latest, according to Yahoo Finance.  

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The head of Proctor & Gamble, who took the job again after a hiatus, told Fortune that he makes it a habit to be up between 5 and 5:30 a.m. and at his desk by 6:30 or 7.

He also takes care to have a good breakfast:  "I used to eat virtually nothing for breakfast. Now I have a V-8 juice, half a bagel, and a cup of yogurt. And I eat five or six times a day. It's about managing your glycemic level. You don't want to boom and bust."

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The Dutch-born Polman gets up at 6 a.m. so he can run on the treadmill in his office. This also gives him time to "reflect on the work day ahead," which is probably pretty hectic at a multinational food and detergent company.

General Motors

Barra, who will replace current CEO Dan Akerson next year is a GM lifer and will be the first female head of a major auto company.

She's in the office before many people even wake up, usually by 6 A.M. according to the New York Times.

flickr/worldtravelandtourismcouncil

The former Coors CEO makes a habit of going for a run or bike ride at 5:50 in the morning and being ready for the day by 6:30, according to "What The Most Successful People Do Before Breakfast."

According to the AP, he might be America's fittest CEO, and completed his first Ironman triathlon earlier this year in 12 hours and 44 minutes. 

It's that effort that's helped him succeed. One of the three life lessons he shared with Bloomberg Businessweek was that "effort is more important than talent." Another excellent lesson was that "anyone who believes he is a self-made man has a very selective memory." 

AP Images

While running PepsiCo, this Marine veteran would run 4 miles every morning at 5 a.m., according to CEO.com. This was the only way he could be sure he would have time for his run and would not get caught up in corporate affairs. He also made a habit of reading The New York Times, The Wall Street Journal, Financial Times, and The Dallas Morning News before heading to work.

Now dean of the Wake Forest University School of Business, Reinemund has invited students and faculty to join him on early morning jogs he calls "Dawn with the Dean," according to the Business Journal.

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For ESPN, Harbaugh chronicled his work week as he prepared for a game with the Chicago Bears. He usually wakes up well before 6 A.M. and often works until 11. On at least a few nights of the week, he sleeps on his office couch in order to wake up earlier, work later, and get down to work faster.

And despite a packed schedule where pretty much every minute is taken up with watching tape, meetings, or practices, he manages to work out almost every day. 

Getty Images / Gareth Cattermole

The famously intense magazine and fashion icon wakes up every morning at 5:45 to play an hour of tennis, according to The Guardian. After that comes a daily blowout at quarter to 7 to maintain her famous hairstyle. 

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The first Bush would get up at 4 a.m., go running, be in the office by 6 a.m. and stay up until 2 a.m. "He was a horror," said a former White House nurse who had to try to keep up with him.

The second Bush kept a similar schedule, going to the office by 6:45 a.m. and often holding meetings at this ripe hour, according to The NYT.

So did W. Bush's cabinet. Colin Powell put in "perfectly appalling" hours, arriving to the office at 6 a.m., and not leaving until after 7 p.m., according to his former students. Condoleeza Rice woke up every day at 4:30 in the morning in order to get to the gym before work.