The number of physically demanding jobs has dropped to less than 10% from 20% in the 1950s, according a study published by economic and social policy researchers at the Urban Institute, meaning the number of jobs that require some exertion were cut in half, leaving more Americans susceptible to desk-job-related health problems.

Here are six office-related maladies and how they can be prevented.

Carpal Tunnel Syndrome

Problem: Any motion that is repeated over and over again can cause injury or pain, according to occupational-health-focused Denver Chiropractor Dr. T. Randall Eldridge. But carpal tunnel syndrome isn't just pain or soreness from too much typing. It's the tingling, numbness, itching or even sharp pain caused when a nerve that runs through the forearm is compressed by swollen ligaments and bones in the wrist, according to the National Institutes of Health.

Prevention: Before you're forced to treat carpal tunnel with acupuncture, drugs or even surgery, stretching and other exercises may help release tension in the wrist, the NIH says. And, contrary to what many believe, your wrists shouldn't actually rest on those cushy wrist pads that sit below your keyboard or mouse pad. They should actually be used as a guide for how high your wrists should be, according to occupational therapist to Marji Hajic. Hajic says hands should hover over the wrist rest and it should only be used as a rest in between bouts of typing.

Lower-Back Pain

Problem: Sitting for hours on end, particularly if you have bad posture, can be devastating to your body over time if you don't get moving on a regular basis. And back pain is actually a major reason for missed work for adults of all ages, according to the Georgetown University Center on an Aging Society.

But bad posture at your desk goes beyond the obvious slouching. Sitting up straight but curving your back too much can be a cause of lower-back pain as well, notes the NIH.

Prevention: Besides being better aware of your posture as you're sitting at your desk, getting regular exercise including abdominal strengthening activities should relieve some of the pressure on your lower back.

Having too fat a wallet in your back pocket can be a bad thing as well. Sitting on a large wallet can put pressure on the sciatic nerve, which can cause sharp back pain, according to UAB Health System in Birmingham, Ala.

Other Joint Problems

Problem: The human body is meant to move, and staying in one position for too long can make joints feel tight. Sitting at a desk especially shortens and tightens the hip flexors, the muscles than help pull your legs toward your body, according to the Yoga Journal. And tight hip flexors can actually contribute to back pain as well since tight hips force the pelvis to tilt forward, compressing the back, Yoga Journal says.

Prevention: Besides getting up from your desk at regular intervals and walking around a bit, the Mayo Clinic recommends a number of stretches that can help loosen up your hips.

Eyestrain

Problem: Office workers who spend hours a day staring at a computer screen might tell you that after a certain amount of time, their vision gets blurry and their eyes generally become more sensitive. Those symptoms (as well as too-watery or too-dry eyes, a headache or a sore neck) could be indications of eyestrain, according to the Mayo Clinic.

Prevention: To prevent eyestrain at your computer, increase your font size so you don't have to squint, suggests Microsoft (NASDAQ: MSFT - News) (though the font on this informative page might cause readers to do just that). You may also want to rest your eyes frequently by looking away from your computer screen and reducing any glare on your monitor, the Mayo Clinic suggests.

Bacteria

Problem: "The desk, in terms of bacteria, is 400 times more dirty than your toilet," University of Arizona microbiologist Dr. Charles Gerba told WebMD (NASDAQ: WBMD - News). "People turn their desks into bacteria cafeterias because they eat at them, but they never clean them. The phone is the dirtiest, the desktop is next, and the mouse and the computer follow."

But bacteria problems at your desk could be more severe than Gerba thinks. Breadcrumbs and other food remnants get can get in between keys on your keyboard, attract rats and lead to unintended exposure to their germs. What's more, many raw and cooked foods need to remain refrigerated, and leaving them out for two hours or more is a food safety no-no.

Prevention: If you frequently eat your lunch at your desk, you may want to make sure you have hand sanitizer and antibacterial wipes to wipe down your work surface daily. That can also protect you from germs sprayed into the air by your coughing and sneezing coworkers.

If your office has a communal kitchen sink with a sponge, the American Dietetic Association suggests using paper towels instead, just to stay safe from bacteria.

The association goes as far as recommending that those who eat in the office bring a refrigerator thermometer and a meat thermometer as well.

Stressful Situations

Problem: Stress can be a problem at work regardless of how physical your day-to-day activities are, but those who do exert themselves on the job can actually use some of their activities to ease their stress. If you're chained to a desk, however, you may be even more likely to have stress-related outbursts.

About one-sixth of workers said anger at work led to property damage, and 2%-3% of workers admit to pushing, slapping or hitting someone at work, according to Reuters.

"With roughly 100 million people in the U.S. work force ... that's as many as 3 million people," Reuters reports.

Additionally, about 22% of U.S. workers say they've been driven to tears because of workplace stress and 9% say that stress has led to physically violent situations, reports RJC Associates, a career development firm.

Prevention: Smaller stressors can be handled with breathing and relaxation techniques at your desk or a break outside of the office, but some conflicts may call for mediation by an unbiased party.

And believe it or not, video games have been suggested as a method for easing workplace stress, according to CareerBuilder.com. With the job market recovering and more companies hiring, however, it's starting to look like new job prospects could be a promising way out of stressful work conditions as well.