You huff and puff through cardio sessions, but that darned scale won’t budge. Your workout might be to blame. Here are six workout mistakes that can slow your results:

You sacrifice good form. It’s important to focus on your form, even if that means lowering the intensity. “You recruit fewer muscles and burn fewer calories when you’re slouched over,” said Geralyn Coopersmith, global director of performance and fitness training at Nike. An added bonus: One study showed that good posture allows you to take in more oxygen, so your workout feels easier even while you’re blasting more calories.

You exercise while parched. Without sufficient hydration, you’ll fatigue faster and your workout will feel tougher than it should. In recent studies, Dan Judelson, an associate professor of kinesiology at California State University in Fullerton, found that exercisers who were dehydrated completed three to five fewer reps per set while strength training. On workout days, drink an ounce of water for every 10 pounds of body weight (i.e., 15 ounces if you weigh 150) one to two hours before exercise. Then keep sipping during and after your session to replenish what you lose through sweat.

You read on the treadmill. “If flipping through a magazine keeps you motivated, by all means do it,” Coopersmith said. “But reading while exercising is so distracting that you’re probably working at an intensity too low to burn a significant number of calories.” Instead, turn on some tunes to increase the duration and intensity of your cardio workout. You don’t have to nix TV shows, cellphones, books and magazines every workout; just leave them behind a couple of times a week so you can focus on intensity.

You hate your workout. No matter how many calories an activity promises to burn, if you don’t enjoy it, you’ll be less likely to do it and won’t reap the benefits. Think of it this way: If you burn 300 calories every time you exercise, but you dread it so much that you skip one session a week, it adds up to 1,200 calories a month. Instead, find a workout you want to do, rather than one you feel like you have to do.

You skip weight training. More than 80 percent of women forgo strength training, a survey by the Sporting Goods Manufacturers Association found. People who pair aerobic and resistance training eat less — 517 fewer calories a day, on average — than those who do only cardio, reports a study in the Journal of Sports Science and Medicine. The combo workouts increase satiety hormones and boost your body’s ability to break down food and stabilize blood sugar, so you feel full longer, said study author Brandon S. Shaw.

You trust calorie-burn estimates. Like most things that sound too good to be true, those digital displays on exercise machines that show mega calorie burns are often inflated. For instance, research presented at the National Strength and Conditioning Conference found that elliptical trainers overestimate calorie burn by an average of 30 percent. But you can still utilize the calorie counters as a gauge of how much you’ve exercised and as a benchmark for ramping up your workouts. Try to raise the number you see on the machine every week, and you’ll continue to make exercise gains.