4 Reasons Your Arms Aren't Shrinking No Matter How Much You Work Out (2024)

No matter how hard you work on your arms, that dreaded loose underarm skin won't go away. Sound familiar?

You may not need to work out more, says Lisa Kinder, a Los Angeles-based personal trainer and star of the 10 Minute Solution: High Intensity Interval Training workout DVD. "The key may be to exercise smarter," she says. Read on for some common roadblocks to success, and what you can do to finally get toned upper arms. (Get a flat belly in just 10 minutes a day with our reader-tested exercise plan!)

Your workouts consist mainly of curls and presses.
Focusing on one area of your body, or "spot training," won't give you the results you want. According to a study in Medicine & Science in Sports & Exercise, women who strength-trained on just one arm for 3 months didn't lose any more fat on that side compared to the other. Exercising your arms will build muscle, but that can remain hidden under fat, explains Kinder. "For toned arms, you have to lose weight all over," she says. Yep, that means cutting calories and eating smarter (our 21-day clean-eating challenge can help!).

MORE:7 Reasons Your Thighs Aren't Changing No Matter How Much You Work Out

You're not pushing yourself hard enough.

If your cardio—walking, cycling, elliptical—is done at one pace, it's time to mix it up. Adding in some short sprints can ramp up your results: In a Japanese study, people who did high-intensity interval training burned about 55% more calories per minute than those who didn't change up their pace.

Try switching between 30 to 60 seconds of high-intensity effort and 15 to 20 seconds of recovery, says Kinder. For the best results, she recommends total-body moves, such as burpees,lunge split jumps,plank jumping jacks,and running in place with high knees. "You'll burn calories while building muscles all over your body, including your arms," she says.

MORE:The 8 Most Effective Exercises For Weight Loss

You're feeling frazzled.

About 4 in 10 Americans say they're regularly under pressure. "Chronic stress can slow or even prevent your weight loss, even if you're exercising and eating right," says Kinder. That's because your body pumps out the hormone cortisol, which ramps up your appetite and encourages the storage of fat in places like your hips, thighs, and, of course, upper arms. It also reduces your levels of testosterone, which may make it harder for your body to build muscle. Getting at least 7 hours of sleep (sleep better with these tips), exercising regularly, and carving out some downtime can help keep your stress in check.

MORE:10 Silent Signals You're Way Too Stressed

You work your arms only once or twice a week.
That's a good start, but you should aim for every other day if you really want results. If you can't get to the gym, body-weight exercises can be just as effective as pumping iron, reports a study published in the Journal of Strength and Conditioning Research.

What's more, they can be done anywhere. A few to try: dips done from a chair or tabletop position; push-ups; and extensions. (Give this 5-minute routine for toned, ageless arms a try.)"Do them in addition to your total-body aerobic workout," says Kinder. Just don't over do it: Kinder recommends alternating days, so you can give your arm muscles a day or two to recover.