Stylish or functional, we love our bags. They’re trendy little—or not-so-little—ways to make us feel secure away from home, because they hold all that important stuff we just might need. But while we’re lugging those extra files, shoes, phones and tablets, we’re damaging the key components of our spines, necks and shoulders.

The American Chiropractic Association says using heavy purses, backpacks and handbags is an “unhealthy fashion statement” that can cause improper balance. Heavy bags cause 31 million Americans to experience back pain at any given time, leading to one of the most frequently cited reasons for missing work.

Dr. Kathryn Montgomery, of Montgomery Chiropractic in Export, Pa., has been in private practice for eight years. She consults many patients with pain from carrying bags that are too heavy. “Anything that shifts position from the anatomical position (think Leonardo da Vinci’s Vitruvian Man) could cause stress,” she says. “Carrying a heavy purse can throw off your natural gait because your muscles are off balance, putting your body into a position that causes it additional stress. A briefcase has the same effect because you are still putting the load to one side.”

That imbalance of weight causes over-stretching, and makes the head rotate or tilt at an unnatural angle, resulting in wry neck, a localized muscle spasm in which the head is tipped to one side. And the shoulders feel the heat, too. “When carrying a bag on one shoulder, the other shoulder gets a lot of very specific pin point pain, which almost feels like a hot poker that irritates the muscles and nerves,” Montgomery says.

Carrying heavy bags could also cause your shoulder to rotate backward, which could affect the vertebrae and discs, the cushions of cartilage that sit between the vertebrae, she says.

Another common injury related to carrying too much is called rib head subluxation, Montgomery says. This is when the end of a rib slips slightly out of the position where it fits comfortably on the spine. “It doesn’t take much to cause discomfort, just a matter of a millimeter,” she says.

Even a heavy suitcase, awkwardly tossed just once into an airplane’s overhead luggage bin, can cause travelers to return home from their relaxing trip in pain, says Montgomery, who sees many neck and cervical sprain injuries from heavy duffle bags. These injuries can cause tingling and even numbness in hands.

Tote it right

The best way to avoid pain from carrying a big bag is to simply carry less weight. Adults should carry no more than 10% of their body weight. The American Academy of Pediatrics recommends children carry no more than 10% to 20% of their body weight. “Five percent is ideal,” says chiropractor Dr. Kathryn Montgomery. Try these tips to lighten the load.

  • Switch shoulders regularly.
  • Leave your big bag in the car, and take a wristlet into the store.
  • With backpacks, use both shoulder straps.
  • Evenly distribute items in the bag.
  • Keep bags close to your body to prevent swaying.
  • Take breaks from carrying the bag.
  • Try using bags with wider straps to help disperse the weight on your shoulder.
  • Avoid wearing high heels while carrying a bag, which can cause hyperextension and back strain.

Guys, what about your wallet?

It was funny when Seinfeld’s George Costanza had an overflowing wallet. But in reality, sitting on those unused membership cards and old receipts can cause misalignment the whole way up your spine. “I had a patient who was a truck driver, and his one shoulder was significantly higher than the other,” says Dr. Kathryn Montgomery. The reason? He spent hours driving while sitting on his wallet. “It had worn out a square in his back pocket,” she says. “I encourage all men to take their wallet out of their back pocket and stick it on the console.”

Just as your feet are your base when you’re standing, the pelvis is the foundation of your body when you’re seated. A wallet creates an uneven platform, which can cause tightness in the lower back from pelvic muscle imbalance. It is often seen in people who sit during much of their workday.

“If you do this over years, it can lead to long-term problems, such as numbness, neuropathic pain, stress headaches and potentially thoracic outlet syndrome (when the blood vessels or nerves in the space between your collarbone and your first rib become compressed),” Montgomery says. Wear your wallet in your front pocket, or at least take it out when you’re seated at your desk or in the car.