Eighty percent of kids in the UK carry bags that weigh up to 20 percent of their body weight, according to research from the charity BackCare. The news could be worse for you.
"With a backpack, the load is evenly spread," says Alan Hedge, Ph.D., professor of ergonomics at Cornell. With a shoulder bag, it's not. Too much weight on one shoulder means your back twists more to one side resulting in an uneven strain—and tension, pain, or even spasms.
Consider the add-ons: You didn't start your day with a 36-ounce bottle of water, but now you're schlepping it everywhere. "1 pint of water is usually 1 pound," says Hedge. Buy what you can drink. Power cords are heavy too. Consider a slim powered battery that you can charge up and store with you, says Boye. Some clip right on to the back of your phone like this one from Third Rail. (www.ThirdRailMobility.com; $89.99).
Streamline: Are you carrying two phones? An iPad and a laptop? A book and a Kindle? "Limit yourself to one phone and an iPad/Kindle," says Boye. And unpack the insurance stuff that never gets unpacked, Hedge adds. You don't need five pens, three notebooks, and 12 USB drives.
Buy smart: You don't have 18 credit cards, so you don't need a wallet that holds 18, says Boye. "The more room you have to fill, you will." Check out some slim, stylish wallets with spots for eight cards from J.FOLD.
Add wheels: It may not be work-appropriate, but when it comes to travel, "wheel rather than carry," says Hedge. Look for a bag with broad wheels that can handle any surface, and make sure the handle is long enough so you're not bending your back, says Hedge. (Don't forget these 8 Rules of Business Travel.) When it comes to an efficient, sleek roller bag, Boye suggests Rimowa.