Learn the features to look for in a back-friendly chair and how to adjust it to prevent lower back pain.

Think about all the hours in a day that you spend sitting, at home and at work. For most people, that adds up to a lot of time, and lower back pain is inevitable if you're spending all that time sitting in a chair that doesn't properly support you.

Choosing the right chair is crucial for avoiding lower back pain. Once you've picked the perfect seat, you'll need to adjust it to make sure it fits you perfectly, preserving the natural S-curvature of the spine and reducing the body’s natural tendency to droop. These adjustments are critical to warding off lower back pain.

"The key thing is to have lumbar support, and to be sitting upright rather than slouched over," says Nick Shamie, MD, associate professor of spine surgery at UCLA School of Medicine, director of spinal deformity surgery at Santa Monica-UCLA Medical Center and Orthopaedic Hospital, and a spokesman for the American Academy of Orthopaedic Surgeons. "Slouching puts added pressure on your lower back and eventually can cause spinal disk deterioration."

Finding the Perfect Chair for Your Lower Back

Here are specific features to look for when you’re buying a chair that will reduce your risk of lower back pain:

• Chair base. Choose a strong, five-legged base to minimize the chances of tipping over. The base should be on casters, to allow you to scoot around and limit the muscle strain and fatigue associated with pushing, reaching, and bending.
• Seat pan. The pan should have some cushioning without being too soft, Dr. Shamie says. It should feature a rounded "waterfall" front edge that slopes slightly down. Be sure to get a chair that allows the height of the seat pan to be adjusted. Tilt adjustment is also a valuable feature.
• Backrest. The lumbar support supplied by a good backrest is one of your best tools for avoiding lower back pain. The backrest should feature an outward curve and be height-adjustable so it fits into the small of the back. The backrest should also be able to move forward and back so that short and tall people will be able to sit comfortably, and the angle should be adjustable.
• Armrests. They should be at least two inches wide to provide proper support and made of soft material to reduce irritation to the nerves and blood vessels in the forearm. Choose armrests that are adjustable in height and width.

Adjusting Away Lower Back Pain

You'll notice that nearly all the seat components come with various adjustment mechanisms. To head off lower back pain, you'll need to tweak the seat to fit your specific form. To do this, you need to:

• Raise or lower the seat pan until the entire sole of your foot rests on the floor, with the back of your knee slightly higher than the seat. This prevents slouching that leads to lower back pain.
• Move the backrest up or down until the lumbar support fits firmly in the small of your back. This will support your lower back and keep it free from pain.
• Adjust the backrest forward or backward until there's a fist-sized gap between the back of your knees and the front of the seat. This reduces pressure on the back of the thighs
• Set the armrests so they provide support for your arms but are still low enough to keep your shoulders relaxed. The armrests should be close enough to support your lower arms while keeping your upper arms close to the body.