Jogging on a treadmill is boring — gain more health benefits from running with these short 20-30-minute HIIT workouts

• Using intervals on a treadmill is a great way to break up the monotony of running inside.
• You can add intervals to your workout by increasing your speed or the treadmill's incline.

Running on a treadmill is a great way to increase your heart rate and get an effective cardio workout. But unless you enjoy doing the same running routine over and over again, it can be a little boring, especially if you run multiple times a week.

One of the best ways to freshen up your time spent on a treadmill is to do some high-intensity interval training (HIIT) runs. HIIT workouts are filled with short bouts of intense exercise followed by shorter rest periods — think sprints followed by walks, or hill climbs followed by running on flat ground.

In addition to spicing up your running routine, research shows that doing HIIT workouts (including sprint intervals) is more beneficial for your body than moderate-intensity continuous training, and it involves shorter workouts. Just some of the major health benefits from HIIT workouts include improved VO2 max, blood sugar levels, blood pressure, and cardiovascular function.

Below are five of the best HIIT treadmill workouts, as recommended by three personal trainers, each capable of giving you an effective and efficient cardio exercise in just 15 to 30 minutes.

1. High-impact sprint workout

Time required: 15-20 minutes

This sprint workout comes from personal trainer, Sophie Allen, of Train With Soph, and is comprised of 10 sets of timed sprints that scales in difficulty based on the runner's fitness level.

For instance, beginners will sprint for 20 seconds, rest for 40 seconds, then repeat, while advanced runners will sprint for 40 seconds, rest for 20, then repeat. The entire workout should take roughly 15 to 20 minutes.

Here's how to do it:

• Warm up for five minutes at a moderate walking pace
• Repeat the following sprint section a total of 10 times
  • For beginner runners: sprint for 20 seconds, rest for 40 seconds
  • For intermediate runners: sprint for 30 seconds, rest for 30 seconds
  • For advanced runners: sprint for 40 seconds, rest for 20 seconds
• End the workout with a five-minute cooldown at a walking pace

Quick tip: Allen recommends holding onto the handrails of the treadmill for added support when you adjust the speed up and down.

2. Combination strength training and HIIT workout

Time required: 20 minutes

This HIIT workout was designed by Brianna Joye, personal trainer and founder of the app, BOLD by Brianna Joye Fitness. It combines walking, running, uphill work, and even a few strength-training and bodyweight exercises:

Here's how to do it:

• Warm up for five minutes at a walking pace (roughly 3 mph)
• Next, get off the treadmill and perform 30 seconds of squats
• Get back on the treadmill and walk for two minutes
• For the next three minutes, perform walking lunges on the treadmill at a slow speed of about 2.5 mph
• For 30 seconds, run at a pace that's 5 mph or faster
• For the last five minutes, walk uphill at an incline of 10 or higher

3. High-impact incline workout

Time required: 30 minutes

This is another workout from Joye, and one that focuses heavily on incline and hill work, with a short burst of sprinting in the middle.

Although incline running is more taxing (and sweat-inducing), it's worth the effort as the benefits are many, including improved VO2 Max (i.e. your body's oxygen uptake), better speed endurance, and improved long-distance running performance.

Here's how to do it:

• Start with a warm up of about three minutes, walking at a speed of 3 to 4 mph
• During minutes 3 through 5: increase the incline to 3.5 with a speed of about 5.5 mph to 6.5 mph
• During minutes 5 through 10: increase the incline to 10.0 and decrease the speed to 3.5 mph
• During minutes 10 through 15: position the treadmill at a 0 incline and perform repeated sprints at a comfortable sprint speed. Follow a cadence of 20 seconds of sprinting followed by 10 seconds of rest, and repeat for 5 minutes.
• During minutes 15 through 30: increase the incline to 12.0 and try to stick to a speed of 3.5 mph
• Position the treadmill at a 0 include and finish with a 3-minute recovery cool-down walk at a speed of 3 mph

4. Low-impact incline workout

Time required: 25 to 35 minutes

This incline workout from Allen is a great low-impact alternative to the routine above, yet still delivers an effective cardio session.

"Try and increase your pace or incline each round, or at least match your pace/incline from

the last round," says Allen. And if you need to increase difficulty, "don't hold onto the hand rails as your incline increases."

This is also the longest workout listed, so you should be comfortable running for at least a half an hour before trying this one:

• Warm up for five minutes at a moderate walking pace
• Repeat the following section three to five times:
  • Start with two minutes of walking at a moderate incline of 3 to 5
  • Follow up with two minutes of walking at a high incline of 8 to 10
  • Continue with two more minutes of walking at the high incline but increase your pace to a slow jog if you can
  • Rest for 30 seconds, then repeat

5. Heart-rate-based interval training from Orangetheory Fitness

This set comes from Rachel Vaziralli, Orangetheory Director of Fitness Design and Education. If you've ever done an Orangetheory class, it's not exactly a HIIT workout but more so a heart-rate-based workout with plenty of interval training.

"A true HIIT workout requires extremely strenuous efforts followed by a lot of recovery between those efforts," says Vaziralli. "Our workouts are challenging but doable with limited recovery time."

For this routine, your goal is to maintain a challenging pace as you progress through the exercise. Each challenging section gets shorter as you go, and your companion recovery sections get longer.

Here's how to do it:

• Warm up for five minutes at a moderate walking pace, followed by 3 minutes of a challenging pace
• You'll now start your intervals:
• Interval 1: Walk or run for 1 minute at a moderate pace, followed by 2.5 minutes at a challenging pace
• Interval 2: Walk or run for 1.5 minutes at a moderate pace, followed by 2 minutes at a challenging pace
• Interval 3: Walk or run for 2 minutes at a moderate pace, followed by 1.5 minutes at a challenging pace
• Interval 4: Walk or run for 2.5 minutes at a moderate pace, followed by 1 minute at a challenging pace
• Interval 5: Walk or run for 3 minutes at a moderate pace, followed by 30 seconds at your fastest sprint pace.
• End with a 3-minute cool down at a walking pace

Best treadmills

Get the most out of a HIIT workout by using high-quality equipment, like these favorites from our guide to the best treadmills.

• Best overall: ProForm Pro 2000 Treadmill, from $1,246.45 at Amazon and ProForm
• Best smart: NordicTrack Commercial 2950, $2,499 at Amazon
• Best budget: Horizon Fitness T101-04 Treadmill, from $649 at Horizon Fitness and Dick's Sporting Goods
• Best folding: LifeSpan TR3000i Folding Treadmill, from $1,099 at LifeSpan and Amazon

Insider's takeaway

Running on a treadmill doesn't always have to be the same tedious process. You can instead change up your routine by doing a HIIT-inspired workout that's just as, if not more, effective than a normal treadmill running routine.

These kinds of workouts include everything from sprinting and incline work to strength training and bodyweight exercises, and are perfect for every fitness level from beginners to advanced runners. And all you need is anywhere from 15 to 30 minutes of time to do them.