6 Best HIIT Treadmill Workouts for a Flat Belly

Truth bomb: Treadmills are an underrated weight-loss tool, and high-intensity interval training (HIIT) is highly effective for shedding belly fat and boosting cardiovascular health. HIIT's intense bursts of exercise followed by short recovery periods are designed to maximize calorie burn and boost metabolism long after the workout is over. For those looking to trim their midsection, HIIT treadmill workouts can support their weight-loss journey by combining the benefits of running with the fat-burning power of interval training.

Maintaining a flat belly becomes more challenging as you age, thanks to hormonal changes and a natural decrease in muscle mass. However, incorporating regular HIIT sessions into your routine can help combat these changes by burning plenty of calories quickly while helping build lean muscle—a crucial component for boosting metabolism and achieving a toned physique.

If you're unsure where to start, we have you covered. We spoke with certified personal trainers who share their top HIIT treadmill workouts for a flatter belly. Keep reading for the workouts and detailed instructions.

Workout #1: 20-Minute High-Intensity Interval Pyramid

Warm-up:

• Begin with a 2-minute walk at 3.0 mph to warm your body up and get your blood flowing.

Workout:

• Run at 6.0 mph for 1 minute.
• Walk at 3.5 mph for 1 minute.
• Increase your running speed to 6.5 mph for 1 minute, followed by a 1-minute walk at 3.5 mph.
• Run at 7.0 mph for 1 minute, then return to walking at 3.5 mph for another minute.
• Continue this pattern by running at 6.0 mph for 1 minute, then walking for 1 minute.
• Run at 6.5 mph for 1 minute, followed by a 1-minute walk.
• Run at 7.0 mph for 1 minute and finish with a 1-minute walk at 3.5 mph.

Cool-down:

• End with a 1-minute walk at 3.0 mph on a 1% incline to bring your heart rate back to normal.

Tips:

Rachel MacPherson, CPT, an ACE-certified personal trainer with Garage Gym Reviews, tells us, "To make this workout easier, decrease the running speed or increase the rest periods. Beginners might prefer brisk walking and light jogging instead of running. To make it harder, extend the high-intensity intervals for an extra challenge."

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Workout #2: Sprinting for Quick Calorie Burn

"Sprinting is an incredibly effective way to burn calories quickly and build anaerobic fitness," explains MacPherson. "This sprint workout is great when you're pressed for time but want maximum results. However, while sprinting is highly effective, it is also very intense. I recommend only doing this type of workout one to two times per week."

Warm-up:

• Start with a 3-minute walk at 2.5 mph on a 1% incline to get your muscles ready.

Workout:

• Sprint at 9.0 mph on a 1% incline for 30 seconds.
• Follow with a 4-minute recovery walk at 2.5 mph on the same incline.
• Repeat the sprint and recovery walk 3 more times, alternating between 30-second sprints at 9.0 mph and four-minute recovery walks.

Cool-down:

• Finish with a 3-minute walk at 2.5 mph on a 1% incline to cool down.

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Workout #3: Progressive Speed Interval Workout

"This workout increases running speed with each interval while maintaining a steady walking pace for recovery. It's good for building endurance and speed in a challenging, manageable way," says MacPherson.

Warm-up:

• Begin with a 5-minute walk at 2.5 mph to warm up.

Workout:

• Run at 5.5 mph for 1 minute, then walk at 3.0 mph for 2 minutes.
• Run at 6.0 mph for 1 minute, followed by another 2-minute walk at 3.0 mph.
• Run at 6.5 mph for 1 minute, then walk for 2 minutes.
• Run at 7.0 mph for 1 minute, followed by 2 minutes of walking.
• To finish the workout, run for 1 minute at 7.5 mph and walk for 2 minutes at 3.0 mph to recover.

Cool-down:

• Finish with a 5-minute walk at 2.5 mph.

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Workout #4: Tabata Treadmill Workout

"Tabata is a form of HIIT that focuses on short bursts of maximal effort followed by short rest periods," explains Kyrie Furr, CPT, a certified personal trainer and performance coach with Barbend. "This workout is designed to maximize fat burn in a short time. It's intense but effective at reducing belly fat."

Warm-up:

• Complete 5 minutes of light jogging or walking.

Workout:

• Sprint for 20 seconds at 90 to 100% effort.
• Rest for 10 seconds (either walking or slow jogging).
• Repeat this pattern for 8 rounds (4 minutes total).
• After completing 8 rounds, rest for 2 to 3 minutes before repeating the circuit 2 more times.

Cool-down:6254a4d1642c605c54bf1cab17d50f1e

• Perform 5 minutes of walking or light jogging.

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Workout #5: Incline Run Workout

"This workout alternates between running at a high incline and walking at a low incline," says Furr. "Running on an incline increases your calorie burn and targets your leg muscles, helping you shed belly fat faster."

Warm-up:

• Complete 5 minutes of walking with no incline.

Workout:

• Run at a 6% to 10% incline for 1 minute at a moderate pace.
• Walk at a 1% to 2% incline for 1 minute at a brisk pace.
• Repeat for 10 to 12 intervals.

Cool-down:

• Complete 5 minutes of walking on a flat incline.

Workout #6: Fartlek Interval Run

"Fartlek involves alternating between faster and slower running segments. This workout is more flexible than traditional interval training, allowing you to adjust your speed based on how you feel," says Furr.

Warm-up:

• Perform 5 to 10 minutes of easy jogging or walking.

Workout:

• Walk or jog at a moderate pace for 5 minutes to set your base pace.
• Alternate between faster and slower segments—2 minutes of faster running, pushing yourself to a challenging pace; 1 minute of easy running or walking to recover.
• Continue alternating between faster and slower paces for 20 to 30 minutes.

Cool-down:

• Perform 5 to 10 minutes of easy jogging or walking to bring your heart rate down.