HIIT Treadmill Workout: 3 Plans and the Right Machine

A HIIT treadmill workout is high-intensity interval training on a treadmill: short, hard efforts with easy walking or jogging in between. A session takes about 12 to 25 minutes, warm-up and cool-down included. We'd begin with two a week and build to three.

You also need a machine that's fast enough for your hard efforts. Below are the specs that matter and which of our treadmills can handle each plan. Jump to the three plans below.

What is a HIIT treadmill workout?

HIIT means high-intensity interval training. You switch between short, hard efforts and easy recovery, round after round.

Mayo Clinic says a typical session might include "a three-minute warmup, four to six repetitions of a 30-second sprint followed by a 60-second active recovery, and a three-minute cool-down." Our Beginner plan is based on the format Mayo Clinic describes, with "hard effort" at 7-8 of 10 in place of "sprint."

A treadmill makes intervals easy to repeat. You set the exact speed and incline, and bad weather never cancels a session.

Does it work? A PubMed meta-analysis found that HIIT raised VO2max (a common measure of aerobic fitness) more than conventional training. The people studied were elite athletes, so take it as a general sign, not a promise.

What your treadmill needs for HIIT

Three specs decide whether a treadmill can keep up: top speed, incline range and motor. Here's how ours compare, from each product page.

The Muscle D screen models list 3.0 HP with 4 HP continuous output. Where a page lists both continuous and peak HP, we compare the continuous number.

The Touch Screen and LED Screen go to 20% incline for hill work, and the LED runs 8 training programs. The STEPR is the fastest at 13.7 mph and connects to Strava over Bluetooth.

The Endurance T50 is missing on purpose. It's a walking treadmill with a 0.1-5 mph speed range, so it can't do the running plans.

Deck, weight limit and power

• Deck size: 60 × 22 in on the T150, 63 × 21.6 in on the STEPR, and 57 × 20.5 in on the T25. A longer deck gives your stride more room at speed.
• Weight limit: 400 lb on the T150, 440 lb on the STEPR and 275 lb on the T25.
• Power: the T150 needs a dedicated 110v NEMA 5-20P outlet and has a 13 ft cord. That's a heavy-duty 20-amp outlet, not the standard household kind, so ask an electrician. The STEPR uses a standard 110V outlet.

Our picks for treadmill HIIT

Body-Solid Endurance T150 Commercial Treadmill

Commercial treadmill: 4 HP motor, 0.5–12.5 mph, 0–15% incline

Our pick for all three plans. Its built-in INTERVAL program runs walking and running speed intervals, and quick keys change speed and incline. It needs that dedicated 20-amp circuit and comes by freight.

Three CUSTOM programs on the T150 let you set speed and incline over up to 16 segments. Check the manual for how segments work before saving a plan.

On a tighter budget, the Muscle D Light Commercial runs 0.5 to 12 mph with a 2.0 HP continuous motor. For a small room, the Endurance T25 folds to 50 × 36 × 64 in. Its 10 mph top speed suits the Beginner and Intermediate plans but caps the Advanced one.

Delivery and space: plan before it arrives

The T150 measures 82 × 35 in and weighs 285 lb assembled. The T25 is 76 × 36 × 57 in and 260 lb. The T25 ships by LTL freight (a shared truck) within 1 business day, with 2-5 days in transit. The T150 also ships by freight.

Before delivery day, do three things:

1. Measure the room and the way in, including doorways and stairs.
2. Leave clear floor behind the belt. Your manual gives the exact clearance.
3. Check the outlet. For the T150, have the dedicated 20-amp circuit ready before the truck comes.

How to set up and start safely

Every treadmill differs, so these steps cover only the basics.

1. Read the manual and follow its safety steps.
2. Clip the safety key to your clothing the way your manual shows. The T150 and T25 both include an emergency stop safety key.
3. Stand on the side rails, unless your manual says otherwise, and start the belt at a slow walk. Then raise the speed in small steps.
4. Use the handrails to get on, get off and steady yourself. Don't hang on during hard efforts.
5. Keep children and pets away. In a recall notice for another brand, the CPSC advised storing the safety key away from the machine and out of children's reach.

How hard is "hard"? Set your speed by effort

The CDC rates effort from 0 to 10, and vigorous effort is a 7 or 8. Its talk test is simple: at vigorous effort, you "cannot say more than a few words without pausing for a breath."

Heart rate works too. The American Heart Association puts hard activity at about 70% to 85% of your maximum heart rate. It estimates your maximum as about 220 minus your age. For a 40-year-old, that's about 126-153 beats per minute.

The T150 and T25 have built-in heart rate monitors. Treat the reading as a guide and check it against the talk test.

Why the mph numbers are only samples

A 6 mph effort is a jog for one person and a sprint for another. So treat our speeds as a first guess.

In your first session, set each hard effort a bit slow. Raise the speed in small steps until the last few seconds feel like a 7 or 8. Write that speed down.

Three HIIT treadmill workouts: Beginner, Intermediate and Advanced

The names match the Beginner, Intermediate and Advanced days on our 30-day calendar, linked at the end. Treadmill belts need a moment to change speed, so press the button a few seconds early.

Beginner HIIT treadmill workout (4-6 rounds, 12-15 minutes)

Move up when you finish 6 rounds at a 7-8 effort two sessions in a row and feel fine the next day.

Intermediate HIIT treadmill workout (8 rounds, about 21 minutes)

Move up when all 8 rounds feel steady and your hard speed has crept up over a few weeks.

Advanced HIIT treadmill workout (8 rounds, about 25 minutes)

Keep going by adding a round, stretching hard efforts to 60 seconds, or trying a format below.

Other treadmill interval formats

• 30/30: 30 seconds hard, 30 seconds easy. Less rest than the Beginner plan.
• 20/40: 20 seconds hard, 40 seconds easy. Fast efforts with plenty of rest.
• Hill repeats: keep the speed and raise the incline for each hard effort. Good for walkers.
• Pyramid: hard efforts of 30, 60, 90, 60 and 30 seconds, each followed by the same time easy.
• Tabata: 20 seconds hard, 10 seconds rest. Treadmill belts need a moment to change speed. If yours takes several seconds, a 10-second rest may not work, so this format may suit other equipment better.

How often and how long should you do treadmill HIIT?

We'd start with two sessions a week, with rest days between, and add a third once two feel steady.

Each session runs 12 to 25 minutes with the warm-up and cool-down, depending on the plan.

Our 30-day calendar includes a lighter week.

A sample week: HIIT on Tuesday and Friday, strength training on Wednesday and Saturday, an easy run or walk on Monday, and rest on Thursday and Sunday.

Cool down and recover

End every session with a 3- to 4-minute easy walk. Mayo's sample session uses a 3-minute cool-down. Then stretch your quads, hamstrings and calves for a few minutes.

Drink some water afterward.

If your legs still feel heavy on the next HIIT day, swap it for an easy walk.

Common mistakes on treadmill HIIT

• Gripping the rails. If you have to hold on, the speed is too high.
• Skipping the warm-up. Never jump straight to your hard speed.
• Too much incline too soon. Add incline in small steps.
• Chasing someone else's speed. Your effort sets the pace.
• Running the same plan for months. Add a round or a little speed every couple of weeks.

Start your HIIT treadmill workout this week

A HIIT treadmill workout is short, hard efforts with easy recovery in between. Pick the plan that fits your level, and use a treadmill that reaches your hard speed.

Want it on paper? Download the 30-day calendar (PDF).

Shop treadmills for intervals