Gym Bag

Before you take the time to pack a gym bag, consider whether the bag fits your needs. It doesn't make sense to lug around a bag that's too big or try to cram everything into a bag that is too small. The right-sized gym bag will carry all of the things you need and be mobile enough to carry on public transportation (like the bus or subway) if needed.

If you plan to shower at the gym, consider getting a bag with separate wet and dry compartments (including one for your cell phone or music player). The strap should be adjustable and rest comfortably on your shoulder without cutting in.

Gym Shoes

While gym shoes might seem obvious, it's important to remember the specific type of shoe you will need for a particular workout. You don't want to show up for an indoor cycling class to find you only have bulky running shoes.

There are great all-purpose athletic shoes to wear to the gym, but you'll benefit from pairing the right shoe for a specific activity. There are a variety of affordable shoes designed specifically for weightlifting, cross-training, indoor rock climbing, and indoor running.

Having different athletic shoes to rotate will also allow you plenty of time to dry out each pair between workouts, which will help you avoid unpleasant foot odors.

Workout Clothes

There is nothing more aggravating than forgetting a critical piece of workout gear. A missing pair of socks can turn an otherwise productive workout into a recipe for blisters and chafing.

Depending on your workout, some gym bag essentials include:

• Clean underwear and/or sports bra
• Fresh pair of gym socks
• Headgear (e.g., headband, hair tie or clip, or a cap)
• Swimsuit, swim cap, and goggles 
• Workout top and bottoms (shorts, sweatpants, or leggings)

Gym Towel

Some gyms require you to bring a towel to the gym floor—and for good reason. Even if you don't overtly sweat, any moisture left behind might be felt by the next person using the equipment.

Cotton towels are usually best in the gym as the fibers are extremely absorbent and will dry in a short amount of time. Microfiber towels can also be convenient because they dry even faster. And cooling towels are designed to reduce your temperature and absorb sweat in the process. 

Many fitness centers provide clean towels for members to use saving space in your gym bag. However, some people prefer to use their towels.

Pack hand sanitizer with your gym bag essentials if you're concerned about sweat and germs. You'll also find that most gyms offer antibacterial sprays and towels to clean equipment before and after use.

Water Bottle

Nobody likes waiting in line at the water fountain, especially after a hard indoor cycling class or HIIT workout. A reusable water bottle makes it easier to stay hydrated and is easily one of your more important gym bag essentials. Some bottles can keep beverages cool for up to 24 hours.

Prices for bottles typically range from under $10 to well over $50. If you choose a reusable plastic bottle, choose one made with non-toxic bisphenol A (BPA) plastic. Newer, vacuum-sealed water bottles should be condensation-free. Glass water bottles should have leak-proof caps and protective sleeves to prevent breakage.

Tunes and Earbuds

Music helps some people "get into the zone" and pace their workout. If you don't enjoy the piped music at your gym, bring along your cell phone or music player. Don't forget your earbuds and make sure that your device has enough battery life to last for your workout.

You'll also want to make sure you have a way to securely carry your device and keep it dry while you exercise. The same applies to your earbuds. It often pays to buy a quality pair that is both wireless and sweat-resistant.

Heart Rate Monitor

A heart rate monitor may not be considered a gym bag essential, but it is nice to have. It's useful for interval training or during exercises in the anaerobic zone.

Wristband-style heart rate monitors are available in all price ranges. You can also go for higher-end models such as the Fitbit Charge 3, which offers functions like a pedometer as well as heart and respiration tracking.

Personal Care Items

Hygiene is important no matter your gym or chosen workout. Beyond freshening up after a heavy workout, you also want to avoid athlete's foot and other common locker room infections.

A shortlist of "must-have" personal care items to include with your gym bag essentials:

• Antifungal spray or ointment
• Bath towel
• Blow dryer
• Body and face moisturizer
• Comb or hairbrush
• Women's or men's deodorant
• Extra underwear
• Makeup and remover
• Menstrual products (tampons, pads, menstrual cups)
• Shampoo and conditioner
• Shower sandals or flip-flops
• Soap or antibacterial body wash
• Spare contact lenses and solution
• Washcloth or scrubber
• Pain relief cream

It often helps to have a dedicated travel bag to accommodate all your personal care items for the gym. You can buy travel-size portions of lotions and shampoos in most drugstores. Stashing a few body wipes in your gym bag can also be handy for those times when you don't have time to shower.

Gym Lock

Many gyms have self-locking combination lockers, but some still require you to bring your own lock. This can be tricky when traveling since not all locks fit all lockers.

To avoid mishaps, call the gym in advance to ask about locks. Leave as many valuables as you can at home or at your hotel. If you feel that the security at a gym is lax, ask if the front desk has facilities to store your valuables. If not, carry them to the floor with you.

Energy Bars

You may keep an energy bar or two among your gym bag essentials for a pre- or post-exercise snack. If you didn't have a chance to fuel beforehand, a high-carb bar is best suited before a workout. Feed your muscles after a workout with a high-protein bar if you won't have a chance to eat a meal.

Membership Card

Many big-chain gyms no longer require you to present your membership card to enter the gym. Instead, many use an app, your phone number, or a fingerprint scan.

If your fitness center still uses a card or key fob, keep it handy in your gym bag. Some cards are tag-shaped and can be secured to a keychain or clipped to your bag. Regular-sized cards can be stored in a gym bag pocket.

If you use different bags for workouts, swimming, or yoga classes, but you need a card for all your activities, keep your card in your wallet.