Contrary to popular belief, burnout doesn't happen simply because you're putting in too many hours. We all know people who work too hard, but who continue to function and even excel professionally.

While we can't always predict it, experts have identified some factors that are likely to contribute to burnout:

Experts have also identified certain signs that could indicate an impending burnout. If you're experiencing any of the following symptoms, chances are you're burned out--or headed there.

1. Perpetual exhaustion

Do you feel like you can never get enough sleep? Do you wake up exhausted every day? Do you feel perpetually tired and at the end of your resources, both emotionally and physically? These can be symptoms of a health problem, but also commonly accompany personal and professional burnout.

2. Unhealthy lifestyle choices

People who are suffering from burnout often don't have the energy or drive to make healthy lifestyle choices. They may eat too much (or too little), choose unhealthy foods or stop exercising. Research also suggests they are more likely to use and abuse alcohol as a way to escape their anxious or depressive feelings.

3. Inability to stop thinking about work

It's normal to think about work in your free time. But if these thoughts are accompanied by feelings of dread, or if they start to interfere with your day-to-day activities, it may be a sign you're on the path to burnout.

4. Stress-related health problems

People suffering from burnout often experience health issues commonly associated with depression and anxiety. These can include gastrointestinal problems, back pain, frequent headaches and low energy levels.

5. Difficulty sleeping

Occasional insomnia is common, but the frequent inability to fall or stay asleep--particularly if accompanied by thoughts of work--can signal burnout. There is also some evidence that insomnia may predict the onset of burnout; meaning if you're struggling with sleep, it's important to work towards good sleep hygiene sooner rather than later.

6. Loss of enjoyment in daily activities

Another symptom commonly associated with depression as well as burnout is a loss of enjoyment in daily activities. While you may have enjoyed your work in the past, you may now feel apathetic or even fearful about it. You may also find you no longer feel satisfied with your personal life, and that activities you once enjoyed no longer hold any appeal to you.

7. Increased irritability at work or home

If you're feeling out of control, it's easy to take these feelings out on those around you. You may be so overwhelmed by your own issues and exhaustion that minor annoyances lead to intense feelings of anger and irritability.

8. Persistent cynicism at work

Workplace cynicism may be characterized by frequent isolation, frustration and pessimism while at work. You may be distrustful of your boss and colleagues, and may be wary or suspicious of their motivations.

9. Frequently missing work

Research has shown that people suffering from burnout are more likely to be chronically late for or absent from work. You may find yourself looking for excuses to miss work, or may lack the motivation to show up on time.

10. Poor job performance

Whereas you once excelled at your job, you may find yourself performing poorly and relying on those around you to pick up the slack. Research into chronic job burnout and daily functioning suggests that an individual's burnout may actually impact the performance of the workplace as a whole: "Individual performance is compromised because burned-out workers need to invest extra time and effort in performing their job. Additionally, collective performance may suffer because healthy employees spend time in helping their sick colleagues, at risk of also damaging their own health."

What to do if you're experiencing burnout

If you're exhibiting any of the signs or symptoms above, it's important that you first speak to your doctor. He or she will likely suggest you implement some of the following strategies to prevent or recover from burnout.

Reduce known stressors at work:
Make healthy lifestyle choices:
Speak with your employer:
Ask yourself whether you should stay in your current job:
Take a leave of absence:
Use your free time for anything other than work:

Have you ever experienced burnout? What were the signs that something was wrong? Share with us below!