Americans are sitting for as many as 13 hours a day — sitting at a desk job, sitting in the car commuting, sitting on the couch at home watching TV.

There is increasing evidence that sitting for prolonged periods of time is bad for your health.

Sitting for more than eight hours a day is linked to an increased risk for heart disease, diabetes, cancer and early death, according to a recent analysis in the Annals of Internal Medicine. And while getting regular exercise helps, exercise does not eliminate the impact of excessive sitting.

The bottom line: Sitting too much could be shortening your life.

The American Diabetes Association is hoping to inspire people to get active and make healthy changes with its inaugural "Get Fit Don't Sit Day" Wednesday (May 6). The association is encouraging employees to post photos of how they and their companies are taking action in the workplace to Twitter at: #GetFitDontSit and on the association's Facebook page.

The association recommends people get up and move at least every 90 minutes throughout the day. Ideas for moving more during the day include the following: take a brisk walk around the building, choose the stairs over the elevator, hold a walking meeting, refill the water bottle at the cooler down the hall or simply get up out of the chair, stand up and stretch for a few minutes by the computer.

The Georgia Department of Public Health has pledged support for “Get Fit Don’t Sit Day.” In a DPH blog post, E. Susanne Koch, worksite wellness coordinator for the Georgia Department of Public Health, is urging employees to stand up and move for three to five minutes for every 60 minutes of sitting. She recommends that people wanting to sit less start off with small, incremental fitness milestones. Start off by measuring the amount of time sitting during the day, and try to eliminate two to three hours during a 12-hour period, she said.

“Individuals who can find opportunities to move throughout the day are best off,” Koch said in the DPH blog. “Find reasons to talk face-to-face with a co-worker versus sending an email; walk around and get a drink of water every hour; stand during phone calls; and set aside time in the evening to engage in physical activities that you enjoy.”