If you’re looking to shed weight effectively and efficiently, you’ve come to the right place. High-intensity interval training is more than just a fitness trend-it’s a scientifically backed method to enhance weight loss and overall health. HIIT, a workout method alternating between brief, high-intensity exercises and rest or low-intensity periods, has quickly gained popularity. In this article, we’ll reveal how these short, dynamic workouts can be your biggest ally during your weight loss journey.
What is HIIT?
HIIT stands for high-intensity interval training. It's a way of training that combines quick, intense bursts of exercise, where you're working out as hard as you can, with short periods of recovery. HIIT can take on many forms, from Group Fitness Classes like cycling to circuit workouts at your gym or even in the comfort of your home. If you've been hearing a lot about HIIT lately, you're definitely not alone. HIIT has taken the fitness world by storm over the past decade or so, with more people discovering it as an efficient means of getting an intense workout.
Jessica Brown, a New York City-area certified fitness trainer and founder of the Glute Recruit, puts it as "an extreme type of workout program that builds endurance, strength, and helps shed weight more quickly than low-intensity cardio." More specifically, HIIT allows the body to achieve a higher heart rate for short periods of time. You cross that high-intensity threshold -usually around 80% of maximum heart rate - when you're almost out of breath or unable to hold a conversation, Brown says. Some super high-intensity HIIT workouts will take you right up to 90% or 100% of your max heart rate for a short time to really crank up the heat. To calculate your max heart rate, subtract your age from 220.
Joel Freeman, a fitness trainer and entrepreneur based in Los Angeles says, "People love that overall feeling of going to 90% to 100% of your max heart rate," he explains. "You feel like you're getting more of a workout because you're breathing heavier and your muscles are burning."
Examples of HIIT Workouts
Megan Wroe, a registered dietitian and wellness manager with Providence St. Jude Medical Center in Fullerton, California says, “For instance, going for a jog and doing 30-second sprints every three minutes is HIIT, as well as doing as many chest presses as possible with the highest weight possible for 60 seconds in between treadmill walks. This type of training stresses your cardiovascular system in a good way, causing your heart rate to speed up and then slow, which ultimately gives you more bang for your buck.”
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Rest periods in HIIT workouts often incorporate active rest, a type of light activity like walking or jogging, that lasts longer than the amount of time you've spent on the strenuous exercise element. And overall, most HIIT workouts are completed in 10 to 30 minutes, which is often less time than you need for a full cardio conditioning or strength training session.
Why HIIT for Weight Loss?
HIIT stands out as an effective weight loss method because it’s a powerhouse at torching calories, not just during but after your workout, too! By alternating between high-intensity bursts and rest periods, your body needs to work harder to recover, thus increasing your metabolic rate. The intense nature of the workout demands significant energy expenditure, which helps target fat loss, not just weight loss.
Calorie Burning and Metabolism Boost
One of the reasons HIIT can help you lose weight, despite short workouts, is that you will burn calories hours after your workout is finished. Due to the intensity of the workout, HIIT can boost your metabolism for hours after exercise. This results in burning additional calories even after you have finished exercising.
Excess Post-Exercise Oxygen Consumption (EPOC)
HIIT-related fat loss may be due to excess post-exercise oxygen consumption (EPOC), which is the amount of oxygen a person’s body uses while exercising.
Fat Loss and Muscle Gain
HIIT can then help burn more fat rather than muscle, which can occur with steady-state cardio. Plus, HIIT can help you trim your waist. People can continue to grow their muscle mass while shedding extra fat in hard-to-reach places like the lower abdomen and thighs.
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Research from 2018 indicates that HIIT may be an effective exercise modality to stimulate muscle size in people with a higher body weight or obesity. One 2022 study also found that HIIT can rapidly increase the oxidative ability of skeletal muscles, causing concurrent gains in muscle mass and a significant reduction in fat mass.
Time Efficiency
For busy folks who are trying to find time to fit in exercise, there's certainly an efficiency appeal to HIIT workouts. Most people can burn the same number of calories in a 20-minute HIIT workout than they can in performing constant cardio or strength training for 45 minutes.
Benefits of HIIT
There are multiple pluses to the HIIT approach: effective workouts, weight loss and health benefits. HIIT is a great way to lose weight in less time. HIIT also increases lung capacity and blood flow within the body.
Cardiovascular Health
HIIT training has loads of health benefits, including strengthening your heart and keeping your blood pressure in check. The goal of HIIT training is to stimulate the cardiovascular system to improve fitness.
Research indicates that HIIT can reduce heart rate and blood pressure in people with overweight and obesity, who are more likely to have high blood pressure. Some researchers have found that HIIT may even reduce blood pressure more than moderate-intensity exercise in these populations.
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Improved Fitness
HIIT training is highly effective at improving VO2 max, which is a key indicator of aerobic fitness.
Blood Sugar Control
HIIT programs may reduce blood sugar levels. High intensity interval training may be especially beneficial for those needing to reduce blood sugar and insulin resistance. For example, research has shown HIIT can reduce blood sugar and improve lipid metabolism in people with type 2 diabetes.
Mental Well-being
Getting out of your comfort zone, exceeding your physical and mental limits, greatly facilitates self-confidence and improves your mood more than moderate intensity continuous training .
Limitations of HIIT
But there’s a cap to what HIIT can do, says Thomas Roe, a fitness trainer and endurance athlete based in San Antonio, Texas. “High-intensity interval training - think group or circuit training and moving from station to station with little to no downtime - can assist you in dropping the weight, as long as it’s combined with a low-calorie diet or nutrition plan,” he says. "You can't out-train a bad diet." What you do in the gym has to balance with what you do in the kitchen. If you're not operating on a caloric deficit - burning more calories in your HIIT workouts than you're consuming - you may not lose weight.
Janet Lee, a doctor of Chinese medicine, yoga instructor and health journalist based in Kansas City, Missouri says, "You really have to dial in your diet. There's really no getting around it," Try to limit your portions and limit your calories. It's calories in, calories out, for the most part."
Not for Everyone
Shaun Carrillo, lead wellness coach at Providence St. Joseph Hospital in Southern California, adds HIIT may not be the best choice for those who are new to exercise or who have joint issues. Instead, he recommends a low, steady cardio workout.
Comparing HIIT to Cardio
HIIT is just one kind of cardio exercise. But what is cardio? Roe explains, “(Cardio is) any form of exercise that elevates your heart rate and oxygen and blood flow throughout the body while using large muscle groups”. Unlike HIIT, cardio workouts last a minimum of 20 to 30 minutes at 60% to 70% of your maximum heart rate. They also lack the intense spikes of activity, and the long duration and steady pace can be boring for some, Freeman says. However, these long workouts can help you build stamina, making them a good tool for weight loss. The burn may be less than with a typical HIIT workout, but cardio still burns calories and fat, helping you reach a caloric deficit.
While you can lose weight with cardio, it tends to be most effective for those transitioning from a sedentary lifestyle to a more active one. Wroe explains, "Over time, this type of movement is really more maintenance - it’s how our bodies are supposed to move, so it doesn’t create stress once your body adapts. This is where many people get stuck in a weight plateau, and HIIT can help move that along.”
In addition to helping support weight loss, cardio, as the name implies, is also really good for your cardiovascular system, or your heart and lungs. It helps strengthen the heart and improve endurance, which are key components of overall health, wellness and longevity. Freeman says, "Cardio is great for the cardiovascular system and overall fat burning. Plus, it releases endorphins (the brain chemicals responsible for creating the sensation of a runner's high)."
When it comes to choosing the best exercise to support weight loss efforts, the key is finding a workout that doesn't feel like, well, work. Christine Mara, a physical therapist with the Orlando Health Jewett Orthopedic Institute in Florida says, "Pick a form of exercise you enjoy participating in and be consistent, even when you don’t see results. You will have times of plateau, and that may be a time to change up your routine or intensity.”
HIIT vs. MICT: A Study
A study compared the effects of HIIT with moderate-intensity continuous training (MICT). 44 obese subjects were randomised and trained with isoenergetic treadmill exercises for 12 weeks: MICT (60% of maximal oxygen peak, VO2peak) or HIIT (3-7 repetition of 3 min 100% of VO2peak interspersed by 1.5 min 50% of VO2peak). 32 subjects (53% male, mean age: 38.5 years, mean body mass index: 35.5 kg/m2) completed the trial. MICT and HIIT showed comparable effect within groups in weight loss (−6.0 kg (−9.0 kg to −3.0 kg) vs −5.7 kg (−8.3 kg to −3.1 kg)), changes in fat mass (−2.9% (−4.4% to −1.4%) vs −3.6% (−5.9% to −1.2%)), fat free mass (−5.3% (−7.8% to −2.8%) vs −5.5% (−8.3% to −2.6%)), diastolic blood pressure (−5.5 mm Hg (−10.6 mm Hg to −0.3 mm Hg) vs −5.8 mm Hg (−11.3 mm Hg to −0.3 mm Hg)) and low-density lipoprotein cholesterol (−16.4 mg/dL (−30.8 mg/dL to −2.0 mg/dL) vs −14.7 mg/dL (−25.6 mg/dL to −3.8 mg/dL)). There was a significant change between groups in VO2peak (HIIT: +461.6 mL (329.3‒593.8 mL); MICT: +170.5 mL (86.7-254.4 mL); p<0001) and duration of sessions (HIIT: 35.0 min (31.7 ‒35.6 min); MICT: 46.5 min (40.2‒48.3 min); p<0.001).
Choosing the Right Approach
Freeman points out, "I always hesitate to say one is better than the other because there's details that go into the question,". He says when working with clients, he always asks how much time the person has and what their physical limitations might be. There is no one-size-fits-all approach to these workouts. If you like a lot of variety in your workouts, HIIT may be the better option because you're moving between different exercises at shorter intervals.
Getting Started with HIIT
Consistency Over Intensity. Starting with 1 or 2 HIIT workouts per week allows your body to adapt to this new form of exercise without overwhelming it.
Important Considerations
HIIT, however, shouldn't be performed every day, Brown adds. HIIT workouts are hard on the body and should be alternated between less intense workouts like walking or yoga to avoid injury. If you're feeling fatigued with heavy legs or (have) difficulty performing your daily routine, it might be a sign that you're overdoing it with HIIT exercise. Lee recommends aiming for two to three high-intensity workouts a week and mixing in strength training and cardio on the other days for maximum results.
Warm-Up and Cool-Down
Warm-Up is Non-Negotiable. A dynamic warm-up increases your heart rate, loosens up your muscles and prepares your body for the high demands of HIIT, significantly reducing the risk of injury. Spend 5-10 minutes on light aerobic exercises like jogging in place, jumping jacks or dynamic stretches to ensure your body is primed and ready. Both HIIT than MICT training sessions included 10 min of warm-up (50% VO2peak) and 5 min of cool-down (50% VO2peak).
Hydration and Nutrition
Hydration is Key. Drinking plenty of water throughout the day, not just right before you exercise, is essential. During your workout, you’ll lose a lot of fluids through sweat, so remember to take small sips of water as needed during your workout. After finishing, rehydrate thoroughly to aid recovery. If you’re engaging in prolonged or particularly sweaty sessions, consider a sports drink with electrolytes to replenish what you’ve lost and prevent dehydration.
Nutrition Fuels Your Engine. What you eat before and after your HIIT workout can affect your performance. Pre-workout, focus on a light meal or snack that combines carbohydrates with a bit of protein; this could be a banana with peanut butter or a small smoothie. These nutrients provide a steady energy source and can help prevent muscle breakdown. Post-workout nutrition is about recovery. Aim for a meal or snack with a good mix of proteins and carbohydrates to repair muscles and replenish energy stores.
Listening to Your Body
Listen to Your Body. While pushing yourself is a part of HIIT, it is crucial to recognize the difference between pressing your limits and overstepping them. If you feel dizzy, nauseated or exhausted, take it as a sign to slow down or take a break.
Rest and Recover. A day or two of rest or lower-intensity activities like walking or yoga can help your body recover and prevent overuse injuries. Incorporating rest days into your schedule is essential for allowing your body to recuperate and repair. Adequate nutrition and sufficient sleep play a vital role in this process.
Sample HIIT Exercises
Here are some exercises you can incorporate into your HIIT routine:
- Jumping Jacks: Start with your feet together and hands at your sides, then jump with your legs spread wide as you raise your arms overhead.
- Squat Jumps: Begin with your feet shoulder-width apart. Sink into a squat position, ensuring your quads are parallel to the ground and your back is flat, not arched. From the bottom of the squat position, jump into the air, keeping your core tight and your tailbone tucked. Modification: Instead of jumping, perform regular squats focusing on form and controlled movements to strengthen the lower body without the high impact on your knees and ankles.
- Plank: Start in a push-up position with your hands under your shoulders and your body forming a straight line from your head to your heels. Modification: Try a forearm plank if a high plank puts too much pressure on your wrists or shoulders.
- High Knees: Start standing with your feet a width apart. Bring your knee to your chest one at a time while pumping your arms.
- Knee Drives: Start in a high plank position. Modification: For a lower-impact version, slow down the pace of the knee drives, focusing on form and engaging the core.
- Reverse Lunges: Stand with your feet hip-width apart with your hands by your chest or on your hips. Step backward with your right leg, slowly lowering your right knee below your right hip to form a 90-degree angle. Modification: Try a step-to-balance if reverse lunges are too challenging for your knees. Step forward with your right foot and balance on your right leg. Swing your left leg forward so both legs are parallel, but do not place your left foot on the ground.
- Burpees: Start standing, then squat with your hands on the ground. Kick your feet back into a plank position, do a push-up, then move back into a squat position. Modification: Modify burpees by removing the jump and push-up.
- Shoulder Taps: In a high plank position, tap your left shoulder with your right hand and then your right shoulder with your left hand. Modification: Perform this exercise on your knees instead of your toes to reduce the intensity and provide more stability.
- Speed Skaters: Start standing, then leap to the left, landing on your left foot while sweeping your right foot behind you to the left, mimicking a speed skater’s movement. Modification: Instead of jumping from side to side, take a significant step to the side and cross your trailing leg behind you, tapping the floor for balance.
Sample 10-Minute HIIT Routine
Combine the exercises listed above for a dynamic 10-minute HIIT session. Perform each exercise for 30 seconds, followed by 15 seconds of rest, to keep the heart rate up and maximize calorie burn.
Here are a few simple examples of HIIT workouts:
- Using a stationary bike, pedal as hard and fast as possible for 30 seconds. Then, pedal at a slow, easy pace for 2 to 4 minutes. Repeat this pattern for 15 to 30 minutes.
- After jogging to warm up, sprint as fast as you can for 15 seconds. Then, walk or jog at a slow pace for 1 to 2 minutes. Repeat this pattern for 10 to 20 minutes.
- Perform squat jumps as quickly as possible for 30 to 90 seconds. Then, stand or walk for 30 to 90 seconds. Repeat this pattern for 10 to 20 minutes.
Making Exercise a Daily Habit
When initiating your new HIIT workout regimen, you just need to carve out a time slot that works for you!
Lee adds that if doing less than a half hour makes exercise more approachable, then start there. "Try to make the most of it. If you're just going to walk on the treadmill for 20 minutes, that's better than sitting on your couch. But if you're going to do 20 minutes, try to get your heart rate up, get the intensity up," she suggests. You can always increase your speed, incline or both to make a more challenging workout. Use that 20 minutes to work hard, and you may be able to burn as many calories as you would in 30 or even 45 minutes, she notes.
Roe recommends enlisting the help of a fitness trainer who has experience with weight loss and asking about their own fitness or weight loss experiences. Trainers who have successfully managed their own weight may be the best because they can relate to your journey and help you create a plan and schedule to reach your goals, he adds.
Building Muscle
Building Muscle Helps With Weight Loss. As you build more strength and muscle, you'll end up burning more calories 24/7, as muscle burns more calories than fat. If you're using a wearable fitness device that tracks calories burned, Freeman says it's best not to get too hung up on the numbers just within your exercise period. "Turn your body into a calorie-burning machine not just for the workout, but throughout the rest of the day," he says. "Sustained weight loss is more attainable by increasing muscle mass (which boosts your metabolism)."
Setting Realistic Goals
Roe also recommends setting realistic goals and finding someone who can keep you accountable, such as a trainer, support group or team.
Lastly, don't let a lack of progress get you down. Brown says, "Weight loss is a journey and doesn't happen overnight. It's important to be patient when losing weight and not become discouraged,". And consistency is key - factor in time to work out each day, just like you do for meal planning.