Choose a Smart Style

The best way to avoid pain is to keep the weight of your bag centered on your body. Imagine that your spine is a stack of blocks. If you carry a heavy load on one side, whether on your shoulder or in one hand, those blocks — your vertebrae — get yanked into a column that’s not neatly balanced. Your body makes accommodations to bear the weight, which means muscles and ligaments become unbalanced, then your posture shifts, resulting in tension that builds up over time, says Mary Ann Wilmarth, a spokesperson for the American Physical Therapist Association and the director of the physical-therapy program at Northeastern University, in Boston. The safest carryall is a small, light backpack, Wilmarth says, since it encourages you to keep your shoulder blades pulled back and down. (See Pick a Better Bag for more bag options.)

If a backpack isn’t your style, opt for a messenger bag with a long, adjustable strap. That will allow you to distribute the weight of the bag between one shoulder and the opposite hip, and you can wear it close to your body. Before you even start loading the bag with your stuff, consider its size and material, as well as its bells and whistles. Even if you don’t carry much, many leather styles are heavier empty than are lightweight nylon, cotton, or canvas ones. “If you want a huge bag with lots of pockets and buckles, I won’t try to talk you out of it,” says Heidi Prather, an associate professor of physical medicine and rehabilitation at the Washington University School of Medicine, in St. Louis, “but you should be even more vigilant about what you put inside.” If you carry a computer and lots of paperwork and you don’t want a backpack, consider a rolling bag.

Divide and Conquer

“It’s easier on your back and neck if you carry two five-pound bags, one in each hand, than one 10-pounder,” says Patrice Winter, a physical therapist and a spokesperson for the American Physical Therapy Association. Also, make use of pockets when you can. “If you can put your sunglasses and keys in a coat pocket and clip your cell phone to your belt, you’ve reduced the weight of the bag hanging off your shoulder by as much as a half pound,” says Winter.

Change Things Up

“It’s natural to hang your purse from your nondominant side so your preferred hand is always free,” says Cynthia Vaughn, a spokesperson for the American Chiropractic Association and a chiropractor in Austin, Texas. But over time this may create imbalances. To avoid developing aches and pains, switch your bag from one side to the other every 10 minutes or so, says Vaughn. Alternate the purse you carry, too, as changing the style of bag you carry from day to day can prevent pain.