According to the National Institute for Occupational Safety and Health, occupational stress originates from a variety of issues, including:

·         Long hours with few or no breaks

·         Employees unable to participate in the decision-making process.

·         Job insecurity and large amounts of impending change

·         Physical danger

Some jobs have more stress than others. That's not to say they're bad jobs, they just require people who are strong enough to handle the increased stress that comes their way. Here are eight of them:

1. Retail Salespersons
Why: Jobs in sales require you to convince customers to spend money. Customers don't necessarily want to spend money and even if they do, they have a variety of places to shop. Salespeople have to prove their merchandise is the best option. If that weren't stressful enough, retail compensation is often commission-based, which means your paycheck is tied to how much you sell.
What they earn: $24,530

2. Doctors and nurses
Why: Doctors and nurses deal with life and death on a regular basis, a pressure found in few occupations. They have to handle patients while accessing an encyclopedia of medical knowledge. Doctors and nurses who work in hospitals or clinics that don't keep regular business hours often work on little sleep and are on call even on days off. In recent years doctors have also been forced to deal with an increase in malpractice lawsuits.
What they earn: Internal medicine physician: $166,420; Registered nurse: $62,480

3. Accountants
Why: Crunching numbers requires attention to detail that can make your eyes cross. Not only are you dealing with a client's finances, but you also have to take into account volumes of rules and regulations that change each year. Plus, you're expected to know about minute loopholes and read tiny print that nobody else does.
What they earn: $44,632

4. Teachers
Why: Elementary and high school teachers put up with a lot. Students aren't always easy to control or motivate. Parents who can't understand why their children aren't doing better often place the blame with teachers. And pressure to prepare students for standardized tests mean they can't always stick to the lesson plans they'd prefer to teach.
What they earn: Elementary teacher: $43,421; High school teacher: $46,531

5. Firefighters
Why: When firefighters are on call, they've got to be ready to respond to emergencies that range from minor car accidents to huge explosions. They might go an entire shift with no emergency or they might get a call that keeps them out for hours. Perhaps most importantly, they're playing with fire literally. That's stressful enough.
What they earn: $44,130

6. Farmers
Why: Agriculture requires constant attention, from waking up early to strenuous physical activity. That alone isn't stressful, but having no control over nature is.  Droughts, floods, fires or other natural disasters can ruin months of hard work, and you can't do much about it.
What they earn: $23,508

7. Automotive assembly workers
Why: The automotive industry has always been volatile as manufacturers respond to the whims of consumers who want coupés one moment and SUVs the next. Add the pressure of assembling vehicles so that people who spend thousands of dollars can travel safely, and you've got a stressful job.
What they earn: $42,480

8. Stock brokers
Why: You can feel a bit helpless working at a job that's at the mercy of the stock market and economy. When things are going great, you reap the rewards, but when the financial climate isn't so great or the future is uncertain, you have no choice but to ride it out. Plus, competition is high for these jobs.
What they earn: $61,151


Source: http://www.careerbuilder.com/Article/CB-1005-Job-Search-8-High-Stress-Jobs/