What muscles does this HIIT workout target?

Your quads, glutes, hamstrings take the biggest hit, with secondary work through core, spine, shoulders. But here's what most people miss about hiit workouts: the primary target is your cardiovascular system, not individual muscles. A 2024 meta-analysis by Dupuit et al — found HIIT reduces visceral fat in perimenopausal women more effectively than steady-state cardio. The 14 exercises in this 20-minute session with Natalia Gunnlaugs are designed to keep your heart rate in the 80-90% zone for short bursts. That's where the metabolic magic happens. Your muscles are along for the ride — and they benefit too.

What equipment do I need for this workout?

You'll need: mat. Don't have these? thick towel, carpet work as substitutes — I've coached women through this with filled water bottles and it works. The resistance is what matters, not the brand. Natalia Gunnlaugs shows form with standard equipment, but anything that adds load will do. Just make sure it's comfortable to grip — slippery objects and high-intensity moves don't mix. This pairs well with a high intensity workout for fat loss approach. This pairs well with a high intensity interval training approach.

Is this workout suitable for beginners?

This is rated intermediate, so it assumes some baseline fitness. But Natalia Gunnlaugs offers modifications: If you cannot jump, you can step, just reverse lunges; Fingertips facing forward or back depending on wrist comfort. If you've been training consistently for 2-3 months, you're ready. If you're brand new, start with a beginner-level workout in this series and work up. Nobody benefits from ego-lifting into an intermediate session on day one. This pairs well with a low impact cardio approach.

How long is this workout?

Approximately 20 minutes, including warm-up and cool-down. Natalia Gunnlaugs wastes zero time — 14 exercises, no standing around, no 3-minute rest periods. The ACSM recommends 150 minutes of moderate or 75 minutes of vigorous exercise per week. Two or three of these sessions gets you there. That's 40-60 minutes per week of actual exercise. The rest of your week is yours.

Are there modifications available?

For every exercise. Natalia Gunnlaugs cues modifications as they come up: If you cannot jump, you can step, just reverse lunges; Fingertips facing forward or back depending on wrist comfort; Lean back onto elbows or all the way down if flexible — I'll say this once: using a modification is not failing. It's choosing the version that lets you maintain form for the entire set. A half-range pushup with a flat back beats a full-range pushup with a sagging spine every time. Pick the version where your technique stays clean.

How many calories does a HIIT workout burn?

The honest answer: it depends on your weight, fitness level, and actual effort. A 20-minute HIIT session typically burns 200-400 calories for a 140-170lb woman working at true high intensity. But here's what matters more than the calorie number: EPOC. Excess post-exercise oxygen consumption. Dupuit et al.'s meta-analysis found HIIT triggers metabolic elevation for up to 24 hours after the workout ends. So the calories you burn during the session are just the opening act. The real metabolic work happens while you're making dinner.

Is HIIT safe for women over 40?

Yes — with appropriate modification and a proper warm-up, which Natalia Gunnlaugs includes. A 2024 systematic review by Huynh et al — found aerobic exercise (including HIIT) significantly improves cardiovascular health in postmenopausal women with no increase in injury rates when progressed appropriately. The key phrase is 'progressed appropriately.' Start with the modification. Build up over 2-3 weeks. If you have joint issues, swap jumping for stepping. HIIT means high heart rate, not high impact. Those are two different things.

How often should I do HIIT workouts?

Two to three times per week, with at least one rest day between sessions. Your body needs 48 hours to recover from genuine high-intensity work. If you're doing HIIT every day, you're either not going hard enough or heading straight toward overtraining. Mandrup et al — demonstrated that three sessions per week was the sweet spot for improving insulin sensitivity in menopausal women. More wasn't better. Recovery is not laziness — it's where adaptation happens.

Hiit Workout No Equipment | HIIT Blast #7

Exercise Breakdown

14 exercises in Workout 7

Warm-up4 exercises

2m 27s

0:15

Warm-up: Low Squat with Thoracic Rotation

“Really press onto the inner thigh”

hipsinner thighsspinequads

low

0:56

Warm-up: Roll Down to Squat Chest Opener

“Open the chest, look a little bit up”

hamstringsspinechestquads

low

1:26

Warm-up: Tabletop Hover to Plank Walk

“Every time you come forward, you're gonna bring those knees close to the mat, but not touching”

corequadsshoulderswrists

medium

2:06

Warm-up: Glute Kickbacks

“Keep the core still and really squeeze the glute to kick the heel up”

glutescorehamstrings

low

Strength3 exercises

10m

4:30

Squat Pulses and Heel Lift Hold

“Try to keep the weight a little bit more onto your heels instead of your toes”

quadsglutescalves

high

9:45

Alternating V-Ups

“Make sure your shoulders and all the back comes off the mat”

corehip flexors

medium

10:30

Reverse Plank Hold

“Squeeze your glutes, engage your core”

glutescoreshouldersarmshamstrings

medium

Cardio4 exercises

11m 45s

3:15

Walkout to Plank with Squat Ladder

“Nice high plank”

full bodycorequadsglutes

high

4:00

Plank Jump to Squat Pulse Ladder

“You wanna bring your chest up each time”

quadsglutescoreshoulders

high

9:00

Jumping Split Squats

“Keep that balance”

quadsgluteshamstringscalves

high

14:30

Finisher: Squat Jump to Pulse Ladder

“Always just one squat jump”

quadsglutescalvescardiovascular

high

Cool-down3 exercises

1m 58s

16:40

Cool-down: Forward Fold

“Relax the lower back”

hamstringslower back

low

17:06

Cool-down: Quad Stretch

“Try to keep the knees quite close”

quadship flexors

low

18:01

Cool-down: Seated Hamstring Stretch

“Relax the head, the neck, all the way down”

hamstringsspineneck

low

Muscles Targeted

Primary

quadsgluteshamstrings

Secondary

corespineshoulders

Equipment & Modifications

Equipment Needed

Don't Have Equipment?

You can substitute with:

thick towelcarpet

Available Modifications

If you cannot jump, you can step, just reverse lunges
Fingertips facing forward or back depending on wrist comfort
Lean back onto elbows or all the way down if flexible

Coaching Highlights from Natalia Gunnlaugs

“Every time you come forward, you're gonna bring those knees close to the mat, but not touching I tell every new client the same thing: if you can't feel the muscle working, slow down until you can. Speed is not the goal.”
Form

“Don't push it too much, though. Know your limits This is non-negotiable — I've seen the injury that happens when you skip this step, and it's not worth the two extra reps.”
Safety

“Little bit faster now than the first round Some days you show up and everything clicks. Other days it's a fight from the first rep. Both count.”
Motivation

“Natalia pushes hard but always gives you an escape hatch. She'll say 'keep going' in the same breath as 'modify if you need to.' That's not a contradiction — it's coaching.”
Form

Health Benefits

If your heart rate hasn't been above 'walking the dog' pace in months and you know it, this 20-minute session is where you start — I designed it for women who want cardiovascular conditioning without spending an hour on a treadmill. If you're in your 30s or 40s dealing with metabolic slowdown, weight creep, or that specific afternoon energy crash — HIIT addresses all three through the same mechanism. You'll need mat and the willingness to be uncomfortable for 45 seconds at a time.

cholesterol jump

90% relevant

Increases HDL (good cholesterol) and lowers LDL (bad cholesterol) through cardiovascular exercise.; Improves insulin sensitivity and glucose metabolism, which indirectly impacts cholesterol levels.; Reduces visceral fat, a key contributor to dyslipidemia.; Builds lean muscle mass, boosting metabolism and aiding in weight management.; Reduces systemic inflammation, a factor in cardiovascular disease progression.; Manages stress, which can influence cholesterol through hormonal pathways.

heart disease risk

90% relevant

improving cardiovascular efficiency; reducing blood pressure; improving cholesterol profiles; enhancing insulin sensitivity; reducing systemic inflammation; maintaining healthy weight

stomach cancer risk

90% relevant

improving metabolic health and insulin sensitivity; reducing chronic inflammation; maintaining a healthy body weight and reducing visceral fat; enhancing immune function; improving gut motility and microbiome diversity

gynecological cancer risk

90% relevant

Improved insulin sensitivity and glucose metabolism; Reduced chronic inflammation; Enhanced immune function; Maintenance of healthy body weight and fat mass; Modulation of hormone levels (e.g., estrogen, androgens); Stress reduction and improved psychological well-being

heart health awareness

90% relevant

improving cardiovascular endurance; reducing blood pressure; improving cholesterol profiles; maintaining healthy weight; stress reduction; improving insulin sensitivity

Relevant For

back painbalancebone densitycardiovascularcore strengthflexibilityhip painknee painmetabolismposturestressweight gain

Frequently Asked Questions

Related Workouts & Topics

About the Trainer

Natalia Gunnlaugs

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From: HIIT Blast

Exercise Breakdown

Muscles Targeted

Primary

Secondary

Equipment & Modifications

Equipment Needed

Don't Have Equipment?

Available Modifications

Coaching Highlights from Natalia Gunnlaugs

Health Benefits

cholesterol jump

heart disease risk

stomach cancer risk

gynecological cancer risk

heart health awareness

Relevant For

Frequently Asked Questions

Related Workouts & Topics

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About the Trainer

Natalia Gunnlaugs