Your negative, moaning, complaining co-workers aren't just annoying; they're also contagious.

When Harvard researchers combed through piles of data from the Framingham Heart Study, a massive undertaking the collected information on thousands of people over decades, they found that it's not just germs that are catching. "Feelings circulate in patterns analogous to what's seen from epidemiological models of disease," reported Wired.

And negativity, unfortunately, is much more catching than happiness. So what do you do if your office contains the emotional equivalent of Typhoid Mary? Sadly, you can't live in a literal bubble, always keeping your grumpiest colleagues and customers at a safe distance lest they infect you. But there is plenty you can do to protect your mood from being spoiled by their complaints and misery.

On Success Consciousness, writer Laura Tong recently outlined a mighty 23 ways to keep colleagues' negativity from bringing you down. Some of these tips will be a little too over-the-top cheerful for some (I, for one, just can't manage positivity mantras or inspirational posters), but several are both practical and powerful. Here are four of the best, along with one more bonus idea inspired from an unlikely source.

1. Dress happy.

Maybe you have a pair of flamboyant socks that make you smile every time you catch a glimpse of them peeking out of your pants. Maybe there's that one yellow shirt that causes you to grin whenever you look at yourself in the mirror. Maybe putting on a concert T-shirt under your suit gives you a little jolt of secret rock 'n' roll energy throughout the day.

Whatever the particulars, most of us have at least some article of clothing that reliably cheers us up. Put it to full use. Tong focuses on brightening up your look, in particular. "Color has an impact on our psychological mood. Add a splash of uplifting color," she advises.

2. Come prepared.

If you know that the talk around the office often drifts to the same depressing topics, it's up to you to come prepared with alternatives and cut the moaners off before they really work themselves up. "Be prepared with upbeat topics to start a conversation. By going first, you'll have more control to ensure the tone stays positive," Tong says.

3. Try radical empathy.

Nope, it's not easy to extend your empathy to that woman two desks over who's complaining to you about the same pointless thing for the sixth time this week. But instead of yelling "Just fix it!" in her face, as you no doubt want to, try to understand her. You'll reap the benefits of putting in the effort.

"Negative chatter and miserable stories can often mask feelings of low self-esteem and inferiority. The empathy you feel will dilute their words and will also make you feel more positive towards yourself, further boosting your mood," Tong says.

4. Start with an unstressed body.

If you were trying to avoid catching the flu, you'd make sure to keep yourself healthy, so that your immune system could be at it's strongest. That means sleeping enough, eating healthy, and getting some exercise. The same approach works for fighting off a negativity infection. If your body is worn down, it will be easier for the office drama to start stressing you out.

"Your self-control, attention, and memory are all reduced when you don't get enough--or the right kind--of sleep. Sleep deprivation raises stress hormone levels on its own, even without a stressor present. A good night's sleep makes you more positive, creative, and proactive in your approach to toxic people," author Travis Bradberry has written.

This is also why Tong recommends you "get a good night's sleep" and "take a short walk or jog" in the morning.

5. Train them with your attention.

What's the first principle of dog training? Generally, ignore behaviors you don't want and reward those you do. It works for humans, too. Don't reward your perpetually gloomy colleagues with your attention when they're caught in yet another negativity loop. Meet complaints and moaning with a simple "OK" or "I see," but respond to more constructive conversation with enthusiastic participation. Repeat until the lesson sinks in.