Cardio work may not always be the most fun training to do, but the benefits, like improved endurance, can help you big time down the line.

The importance of aerobic exercise on health and weight management has been found numerous times in academic studies. But sometimes, spending 60 minutes on the elliptical can be worse than going to the in-laws' for dinner.

Long Slow Distance (LSD) training, otherwise known as low-intensity aerobic exercise, is important to include into your workout regimen, but sometimes our time is cut short and we want the most bang for our buck when it comes to calories burned. This is where interval training steps in…and forget about the “fat-burning” zone—that was like, so 1980's.

Other studies have found that shorter, high-intensity workouts can have similar physiological changes compared to longer low-intense workouts. This serves great for you because your workouts can be shorter and less boring. But we'll warn you now—they’re not going to be easier!

1. Go the distance

We all know that some training days can feel like a million bucks, while others can feel like a slog. Instead of timing your intervals, go by how much distance you cover. This will accommodate for daily fluctuations in energy levels and will give you something different to focus on.

The workout: Set your treadmill to distance mode. Choose a set distance to cover per interval, say ¼ mile, ½ mile or mile. Run that distance as fast as you can. Follow that with an active rest (easy jog) running the same distance as the “hard” interval.

For example, run a ¼ mile and jog a ¼ mile. Repeat for 20 minutes. Boom. Now pick yourself up off the floor and hit the showers.

2. Do the time

Timing your intervals is one of the most common methods of interval training. The “Tabata Protocol” has exploded since its inception in 1996. This form of high-intensity interval training is only 4 minutes long and is broken up into 20- and 10-second intervals. Basically, hammer as much as possible for 20 seconds and rest for 10. Repeat until the 4 minutes is up. There’s one stipulation, though: the hard is meant to be at 170% max VO2, basically meaning 100x harder than all-out. This is obviously extraordinarily intense and is quite difficult even for the fittest beast out there. Here’s a protocol to help you get to beast mode in 6-weeks.

The workout: On a spin bike, set the resistance to all-out. (In the academic study where the 20-10 protocol was tested, the subjects were seated for the entire protocol. You can either sit or stand or use a treadmill. It doesn’t matter, as long as the effort is maxed.)

Perform each workout twice each week. Begin and end each session with 5-minutes at an easy pace.

Week 1-2: Start with the opposite – 10-seconds hard and 20-seconds easy. Repeat for 4-minutes.

Week 3: Progress to 15-seconds hard and 15-seconds easy. Repeat for 4-minutes.

Week 4: Progress to 20-seconds hard and 20-seconds easy. Repeat for 8-rounds. This will be slightly greater than the usual 4-minutes.

Week 5: Drop the break to 15-seconds and stick with the 20-seconds hard. Perform 8-rounds.

Week 6: Here we go! 20-seconds hard and 10-seconds-easy. Perform 8-rounds for four minutes of fat-loss hell.

3. Go to the beat

It wouldn’t be a “cardio article” without mentioning your heart rate. Your heart rate responds to the intensity of exercise and has been shown to be related to your subjective perception of how intense or “hard” an exercise bout is. The higher your perception of difficulty, the higher your heart rate. Duh!

Many professional athletes use heart rate monitoring in specific workouts to focus on different physiological acclimations—what’s referred to as Energy System Development. Just sets of 5 reps have a different effect on the body compared to sets of 12, running at 90% max heart rate (MHR) has different physiological effects compared to running at 65% MHR.

Let me break this up into 3 categories:

 1. 60-70% MHR – Cardio workouts in this category focus on improving your aerobic capacity and build the foundation for faster workouts. At this intensity, you should be able to carry a conversation. This is the intensity most trainees use when they step onto a treadmill.

 2. 70-80% MHR – Workouts in this category focus on improving your body’s ability to manage high concentrations of lactate and other metabolic by-products. The body produces high levels of lactate at this intensity but learns how to utilize and remove it from the muscles, allowing them to sustain a high power output for a greater duration.

 3. 80-90% MHR – Workouts at this intensity focus on improving your VO2-Max, basically, how much oxygen you body can utilize for a given activity (running, cycling, ellipticling, etc.) based on your body weight, age and sex.

The workout: Choose category 2 or 3 and put on your heart rate monitor. Use the 220 minus your age equation to get a rough estimate of your MHR. Perform a 10-minute warm-up at 60% MHR and bang out 5 x 3-minutes intervals with 2-minutes recovery. Keep the recovery active by jogging/cycling at 50% MHR. This will help get the metabolites out of your legs and prepare you for the next interval. Follow up with a 5-10-minute cool down at 60% MHR.

4. Run unstructured

Fartlek (färtlik) is a Swedish term that translates to speedplay or unstructured interval training. This is a common method of training for elite runners and triathletes. Essentially, this type of training incorporates fast and slow efforts, similar to interval training, but differs in that its unstructured and there is no stopping until you’ve completed the total running time.

The workout: Chose a trail and a time period to run—say, 30 total minutes. Choose landmarks to sprint to and landmarks to jog to. Change the distance between landmarks and go by feel, but don’t cut yourself short and jog most of the way. Make it challenging and put in a good effort. Don’t worry about time and make sure not to stop until the 30 minutes is up.

5. Climb a hill

Hill repeats are crazy cardio-boosters that can improve strength and explosive power. The high-knee lift, pumping arms and powerful toe-off, can spark new levels of aerobic power and some crazy fat loss. Hills are a bit easier on the body compared to sprinting on a flat surface. They force a forefoot landing and require a constant fight.

The workout: Find a semi-steep hill, gravel preferably, and sprint up! It’s that easy. Sprint for roughly 15-seconds. Stop. Find your breath and walk down. Walking down will be easier on your legs compared to running because of the reduced eccentric stress. Repeat 8-12 times and call it a day.

6. Create flow

Don’t go all-out. “It’s one thing to push yourself to extremes, but you can actually get a better workout by tuning into what’s happening to your body during the day,” says Jenny Hadfield, running coach and author of Running for Mortals: A Commonsense Plan for Changing Your Life with Running. If you’re following up a hard day on the trails with a treadmill run, pushing through another hilly workout will cause further fatigue and detriment. Instead, break up high intensity workouts, and ebb and flow between hard and easy to avoid hitting a point of diminishing returns. Follow a hill workout with a cross training day or easy day of flat terrain.

7. Re-work your warmup

Counteract a workday’s worth of sitting with a slow-speed, backwards-walk warmup to open up the hips. Then, integrate a slow side shuffle into the routine. “A slow lateral walk at a 3%-5% incline is a great strengthening warmup or cool-down exercise that targets the adductors,” says Hadfield. Here’s how to weave it into your warmup: follow 30-60 seconds of forward walk with 30-60 seconds of walking backwards at 1.5 miles per hour. “The slower the better,” says Hadfield. “If you’re just shuffling along, you’re not going to get the muscle activation you would if you’re deliberately contracting.” Next, laterally walk for 30-45 seconds until your hip is fatigued, then switch. Repeat 4-5 times.

8. Don't hang on

Fatigue might tempt you to grab onto the handrails for support, but you’re better off coming to a full stop before taking a breather. For safety reasons, always step off. The caveat to the rule: if you’re learning how to use a treadmill or you’re working on balance issues.

9. Work it out

Full schedule? Work out while working with a little intentional movement. Make your treadmill your workstation and complete simple tasks like answering phone calls or replying to emails while keeping a one mile per hour pace, says Hadfield.  

10. Mimic the race

“Track repeats, tempo runs, and a long run can all be done on the treadmill,” says Bill Pierce, Professor and Chair of the Health Sciences department and lead author of Run Less, Run Faster. Whether you’re seeking a change of pace or using the treadmill to simulate a race’s environmental conditions, take advantage of the treadmill’s automatic elevation options. If you live where there’s flat terrain but you’re planning to tackle Boston, you can simulate the racecourse by adding hills to your training run.

11. Ditch the programmed “fat burn” setting

Don’t be fooled by any fat-burn button. The lower intensity just means that a higher percentage of your caloric expenditure is from fat. You’re still always going to burn more fat running faster than you are running slower. For example: Pierce says if you run 10mph and 60% of your energy comes from fat calories, you might burn 100 calories per mile. But if you run 6 mph and 40% of your energy comes from fat, you may burn 300 calories per mile. Basically: ramp up your speed, and your fat burn doubles.

12. Skip the weights

Adding in weights might put on muscle; but it could also put you off balance. “Weights can change your biomechanics and the point of impact, which leads to injury,” says Pierce. Save your strength training for a later workout.  

13. Mix it up

Take advantage of the stationary benefit: Running on a treadmill puts heart rate and pace stats at your fingertips, giving you ultimate control over effort and speed. Try an anything-goes workout: increase your incline for the first interval, then activate the quads, calves, and hamstrings with a decline descent. Close with a challenging incline run that picks up the pace. “If someone runs at 1% incline and another person mixes it up—and runs on a 1%-3% incline on hilly terrain—the person who’s running hills is probably going to have more fun and get in a better workout,” says Hadfield. Don’t feel like overthinking? Use the treadmill’s constant momentum as motivation to run a low-level hill program or an interval workout.