Cardio, cardio, cardio. Aside from diet changes, cardio may be all you hear about when you're trying to lose weight. But can your fat-burning workout plan really be as simple as getting in plenty of cardio?

"Cardio is great for burning calories, so it's a great place to start when you're trying to lose weight," says Lauren Murray, health fitness coordinator and personal trainer at Houston Methodist. "Plus, cardio has other benefits, such as improving your heart and lung health, lowering your blood pressure, regulating blood sugar and improving cholesterol levels."

But, Murray points out that there's more to burning fat than "just getting some cardio in" — and it shouldn't be the only thing you do. Keep these three things at the top of your mind while creating your weight loss exercise plan.

Make sure you're hitting your fat-burning heart-rate zone

To get a good calorie burn during your cardio workout, Murray says you'll want to be sure it's moderate or vigorous in intensity. That's because the higher the intensity, the more calories you burn.

But, what's considered moderate or vigorous for you may not be what's considered moderate or vigorous for someone else. To determine what makes your cardio workout moderate or vigorous, you'll need to do a few calculations to find your target heart rate for each intensity level.

For moderate intensity, you'll need to work out at 50-70% of your max heart rate. For vigorous exercise, you'll need to work out at 70-85% of your max heart rate.

You can find your target heart-rate zone by doing the math yourself (using our guide below), or you can use an online calculator. Once you find your target heart-rate zone, you’ll need to monitor your heart rate while you're exercising.

And speaking of intensity, we mean it when we say that the higher the intensity, the more calories you burn.

High intensity interval training (HIIT) can help you burn more calories

High intensity interval training, or HIIT, has been one of the top fitness trends for the last few years — and for good reason.

"HIIT is one of the most efficient and effective exercise formats," says Murray. "Many studies have shown that working your hardest is key when it comes to losing weight and increasing your metabolism. These workouts typically give you more bang for your buck, with a lot of calories burned in a short amount of time."

HIIT is basically an all-out effort that consists of a quick but intense burst of exercise that's followed by a short period of active recovery — and then repeated several times.

"Another advantage of HIIT is that it interrupts the repetitive motions our bodies can get stuck in during some traditional cardio workouts," explains Murray. "Repetitive movements for extended periods of time can lead to pain and injury — and adding variety to the motions our body is making during workouts is a great way to limit that risk."

(Related: 5 Questions About HIIT Workouts, Answered)

Strength training boosts your resting metabolism

While it's not a bad idea to make cardio the cornerstone of your fat-burning workout plan, it shouldn't be the only thing you do.

One of the many benefits of strength training is that the muscles and lean body mass you gain while lifting weights increases the overall calories you burn during the day.

"One thing that many people don't know is that strength training can boost your resting metabolism, which is the amount of calories you burn at rest," explains Murray. "Yes, minute-for-minute, cardio is a great way to burn calories. But strength training can help you continue to burn calories throughout the day — even after your workout is over and your body is resting."

It might sound intimidating, but Murray says it doesn't have to be.

"Your own body weight is a great piece of equipment itself," says Murray. "There are movements and exercises you can do to improve your strength without ever touching a piece of gym equipment."

(Related: Why You Should Be Strength Training At Least Twice a Week & How to Do It)

So, if you're nervous about picking up weights, Murray recommends starting with body weight exercises. Then, when you're ready, you can slowly add free weights or weight machines into your workouts.

How to calculate your fat-burning heart-rate zone

For instance, a 30-year old's max heart rate is 190 bpm, and he found his RHR to be 70 bpm. This means his HRR is 120 bpm. After plugging these values into the formula, he found his moderate intensity exercise zone begins at 130 bpm and caps out at 154 bpm. While exercising, the time his heart rate is between 130 and 154 bpm is considered moderate intensity and the time their heart rate is above 154 bpm is considered vigorous intensity.