A recent study published in an American Psychological Association journal, Emotion, suggests that early birds are generally happier than night owls.

More than 700 respondents, ranging from ages 17 to 79, were surveyed and asked about their emotional state, health, and preferred time of day.

Self-professed "morning people" reported feeling happier and healthier than night owls. Researchers hypothesize that one of the reasons could be because society caters to a morning person's schedule.

It's certainly true that the working world does. Working "9-to-5" is more than an expression, but a standard shift for many Americans. It also stands to reason that those who like rising with the sun are also the most productive employees in the office.

Do you want to be more like them? Then take note of the tasks these high-functioning, productive, and more awake employees have completed before lunch:

1. They make a work to-do list the day before. Many swear by having a written to-do list, but not everyone agrees on when you need to compose it. According to Andrew Jensen, a business efficiency consultant with Sozo Firm in Shrewsbury, Pa., the opportune time to plan a day's tasks is the night before. "Some people like to do the to-do schedule in the morning, but then they might have already lost office time writing it out," he says. "It helps to do that to-do schedule the night before. It also will help you sleep better.

[In Pictures: 10 Ways to Boost Work Productivity.]

2. They get a full night's rest. Speaking of sleeping better ... lack of sleep affects your concentration level, and therefore, your productivity. Whatever your gold standard is for a "good night's rest," strive to meet it every work night. Most health experts advise getting a minimum eight hours of shut-eye each night.

3. They avoid hitting snooze. Petitioning for nine more minutes, then nine more, then another nine is a slippery slope that leads to falling back asleep and falling behind on your morning prep. Ultimately it also leads to lateness. "Anyone can be made into a morning person," Jensen says. "Anyone can make morning their most productive time. It could be that for the entire week, you set your alarm clock a little bit earlier, and you get out of bed on the first alarm. It may be a pain at first, but eventually you'll get to the point where you're getting your seven to eight hours of sleep at night, you're waking up with all your energy, and accomplishing the things around the house you need to before going to the office."

4. They exercise. Schedule your Pilates class for the a.m. instead of after work. "Exercise improves mood and energy levels," Jensen says. Not only that, but "there have been studies done on employees who've exercised before work or during the work day. Those employees have been found to have better time-management skills, and an improved mental sharpness. ... Those same studies found these workers are more patient with their peers."

5. They practice a morning ritual.Jensen also recommends instituting a morning routine aside from your exercise routine. Whether you opt to meditate, read the newspaper, or surf the Web, Jensen says "it's important to have that quiet time with just you."

6. They eat breakfast. Food provides the fuel you'll need to concentrate, and breakfast is particularly important since it recharges you after you've fasted all night. Try munching on something light and healthy in the morning, and avoid processed carbs that could zap your energy.

7. They arrive at the office on time. This one is obvious, right? Getting a full night's rest and keeping your sticky fingers off the snooze button should make No. 7 a cakewalk. If you're not a new employee, then you've already figured out the length of your average commute. Allot a safe amount of time to make it to work on schedule.

8. They check in with their boss and/or employees. We all know the cliche about the whole only being as good as the sum of its parts. In other words, if your closest work associates aren't productive, then neither are you. Good workers set priorities that align with their company's goals, and they're transparent about their progress.

9. They tackle the big projects first. You can dive right into work upon arriving in the office, since you made your to-do list the night before. And Jensen suggests starting with the hardest tasks. "Don't jump into meaningless projects when you're at your mental peak for the day," he says.

10. They avoid morning meetings.If you have any say on meeting times, schedule them in the afternoon. "You should use your prime skills during the prime time of the day. I believe that mornings are the most productive time," Jensen says, also noting that an employer who schedules morning meetings could rob his or her employees of their peak performance, and ultimately cost the company.

The exception to this, he adds, is if your meeting is the most important task of the day. "Sometimes you have to schedule a crucial meeting, or a client meeting, in which case you'd want to plan for a time when employees are at their peak."

11. They allot time for following up on messages. Discern between mindless email/voicemail checking and conducting important business. Jensen's company, Sozo Firm, advises clients that checking their inbox every couple of minutes takes time away from important tasks. Instead, set a schedule to check and respond to email in increments. Consider doing so at the top of each hour, to ensure that clients and colleagues receive prompt responses from you.

[See How to Use Your Work Email Efficiently.]

12. They take a mid-morning break. Get up and stretch your legs. Or stay seated and indulge in a little Internet surfing. According to Jensen, it's actually good to zone out on Facebook and Twitter or send a personal text message or two. "You should take 10-minute breaks occasionally," he says. "Companies that ban any kind of Facebook [use], texting, or personal calls can find it will be detrimental. Those practices increase employee satisfaction."

Just be sure not to abuse the privilege. "The best employees will respect their employer's time, and the worst-performing employees will find a way to waste time even if the company forbids personal Internet use," Jensen explains.