Keeping your sneakers in your gym bag until you’re ready to work out will help to keep the soles clean and in good shape so that you don’t have to replace 'em every few months.
A change of clothes
This is a no-brainer if you go right from the gym to the office. Even if you’re not, though, it can be nice to leave the gym feeling fresh and clean rather than sweaty and worn-out.
Unless, of course, you like listening to clanging weights, loud grunting, and whirring machines while you work out.
Comb and hair product
Useful if you’re heading straight to your next engagement after the gym to make sure you leave looking as polished as you did coming in.
It’s a little neurotic, but we’d rather not take our chances by stepping on whatever’s been on the floor of the shower that day.
Soap and shampoo
Unless you work out at an absurdly luxurious gym that stocks their locker rooms with the good stuff, you should avoid whatever industrial-grade, skin-decimating products are available and bring your own.
If you want a quick boost of energy, a water bottle with a scoop of pre-workout powder will amp you up right away. There are lots of options, but they all do similar things: slightly repress your appetite and give you some extra energy so you can focus on your workout (instead of that e-mail you forgot to send, or what’s for dinner). And if you want to refuel after a weightlifting session, a protein shake makes for an easy and filling post-workout drink to get more muscle-building protein into your diet.
Books or magazines
If you prefer to camp out on an elliptical machine instead of bench pressing, kill two birds with one stone and work through your reading list while you exercise.
Pen and paper
If you’re serious about weight lifting, you can keep a written record of your lifts to check your progress against. Can also come in handy for writing down phone numbers if you happen to catch someone’s eye.