Jill Koegel, a registered dietitian and certified as a personal trainer, blogs for momaha’s sister site, LiveWellNebraska.com

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One of the most commonly misunderstood variables of exercise is the concept of intensity. Determining how “hard” to workout has been a topic of debate for a long time.

For many, the purpose of working out is to train for an event. Some people use exercise to gain muscle or simply maintain an overall healthy lifestyle. But for the sake of appealing to the majority, the following explanation will focus on weight loss.

For starters, exercise intensity affects what kind of calories you burn. In any workout, a mixture of carbohydrate and fat are used to create the energy for muscle contraction and physical activity. Lowering workout intensity will offer a higher percentage of fat burned than higher intensity exercise. Sounds like a dream, right? Workout easier and burn more fat? Let me explain.

While the percentage of fat calories burned increases when intensity decreases, the total number of calories burned is drastically less. So unless you increase the duration of your exercise, your total number of calories/fat grams burned is less than in a harder workout. Bottom line: If your workout is easy, it has to be longer if you want to burn more calories.

The reason I tell many people to focus on a specific distance is because whether you run, jog or walk that distance, the calorie burn is approximately the same. The variable, of course, is the duration of the workout. It takes longer to walk three miles than to jog or run it.

Interval training is another hot topic when it comes to making workouts more efficient. This type of training alternates high intensity bouts of exercise with lower intensity “recovery” periods. Working out like this forces your body to alternate its main source of fuel between sugar and fat, and this has been shown to improve aerobic fitness.

The “5 – 4 – 3 – 2 – 1″ interval workout: Challenging, achievable and rewarding.

1. Start with a form of exercise you’re comfortable with, like jogging on a treadmill, for five to ten minutes.

2. Increase the intensity by adding incline or speed for another five minutes of “hard” intensity. Determining what is “hard” is sometimes the most challenging part.

3. Follow this with five minutes of “easy” intensity, which should allow you to recover.

4. Complete four minutes hard and four minutes easy.

5. The three, two and one minutes of both hard and easy intervals.

6. Complete the workout with five minutes of cool down.

For weight loss, burning a high number of total calories, while also preventing injury, is key. Having a personal trainer, physical therapist or other qualified professional who can assess your form and intensity level is helpful, too. Doing a variety of exercises, intensities and durations is the best way to keep your body “confused” and ultimately burn the most calories.

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