By now you’ve heard about the negative health effects of sitting for long periods of time — that research shows spending eight or nine hours at a desk raises the risk for chronic conditions like heart disease, cancer and diabetes.

Apparently, so have many employers, insurance companies and federal agencies such as OSHA, the Occupational Safety and Health Administration. Over the past five years, there’s been a push to improve work stations and encourage workers to alternate between sitting and standing. The effort has produced a number of innovative products designed to help workers be more mobile, such as standing and treadmill desks.

If you’re tempted to try one of these products, it’s important to know how to use it.

“The point of examining work stations is to see what we can do to help make the worker safe,” says Langdon Dement, an adviser at UL’s workplace health and safety division who has a special expertise in ergonomics. “We look at hazards [for injury] before they occur.”

Here, Dement evaluates the ergonomics of office furniture ideas that aim to make workers more mobile.

Related: How to Set Up a Feel-Good Office

Standing desk

Dement says the concept of standing desks, or “sit/stand workstations,” is good, but there can be issues with standing all day.

Standing for hours will make you tired, for instance, and you may start to shift from one leg to another or lean on one hip, which can overwork one side of your body. You also might lean onto the desk and cause stress on the arm or wrist bearing the majority of your body weight.

The surface you stand on and the type of shoes you wear can have an impact on your body as well. “If you don’t have an anti-fatigue mat under your feet, you’re putting a lot of stress on your knees and back,” says Dement. “If you’re wearing heels and don’t change into tennis shoes for the standing periods, you’re going to start to feel stress in your knees and lower back. Sooner or later, you’re going to start holding tension in your shoulders and neck, too.”

Related: 5 Ergonomic Mistakes You’re Probably Making

Workout ball

Using a workout ball instead of an office chair is trendy, but Dement says it’s not the most ideal for the workplace.

“If you aren’t able to maintain that posture [in a chair] for an extended period of time, it can be more difficult to maintain that posture on a ball,” Dement says. “It’s not a chair, so it’s not ergonomically supportive. It’s more of piece of workout of equipment, because it increases fatigue on the body. Short-term it’s probably fine, but most of the ergonomics research produced on the ball [as an office chair] shows that a chair is better for you when you’re at work.”

Treadmill desk

The treadmill desk usually consists of a slow-moving treadmill with a work surface built on or above the screen that transmits pace and heart rate. “The point is you can keep the blood flowing and you aren’t sitting still all day,” says Dement. “But you’re potentially adding more hazards than if you’re standing still.”

Even using a treadmill for exercise has its risks. In fact, treadmill-related accidents made up 37 percent of all injuries related to exercise equipment, according to a report in the Wall Street Journal.

Related: 9 Ways to Protect Your Joints on a Treadmill

Tablets and laptops

“People are going straight to tablets or using laptops more at work,” says Dement. Taking a laptop into a conference room or meeting is fine, he says, but sitting on a couch with it on your lap for long periods — at home or while on the road, say — causes stress on key areas of the body.

“The keyboard is smaller typically, and you’re looking down a lot more, and there’s also contact stress on wrists since they rest on the computer,” Dement says. It’s particularly bad for the neck and back to work on the couch for an extended period of time, he says. “The key to ergonomics is to maintain neutral positions of the body.”

Rather than invest in a treadmill desk, exercise ball or some other alternative to a regular desk and chair, Dement suggests doing this instead: At the beginning of the day, start with some stretches. Every hour, take a 5- to 10-minute break to walk around, stretch, and rest the eyes. “If you’re doing things like this, you’re at least not going to be in the same position, and you aren’t going to be as prone to the issues that come with sitting at a desk all day.”

Related: 4 Ways to Stay Sane While Working from Home

Chelsea Rice is a freelance health writer living in Boston. She's written for, The Boston Globe, HealthLeaders Media and Minority Nurse magazine.