HIIT vs SIT // What Everyone Should Know About Smarter Interval Training at Shred415

At Shred415, we’re all about smart, intentional training. That means knowing how to train for results, not just going through the motions. And when it comes to time-efficient workouts that deliver, both HIIT and SIT are at the top of the list.

Whether you’re just starting out or leveling up your performance, understanding the difference between HIIT and SIT can help you train with purpose, avoid burnout, and make the most of every class.

​​What is SIT and HIIT?

HIIT, or high-intensity interval training, features short bursts of challenging effort (like a jog or run on the treads), followed by brief periods of rest or active recovery.

SIT, or sprint interval training, is similar but takes intensity to another level. At Shred415, we approach SIT as PIT (Push Interval Training) because it’s not just about sprinting; it’s about pushing your limits, whatever your pace. It involves going all-out for a few seconds (typically 10 to 30), followed by longer recovery windows.

According to Healthline, SIT is an anaerobic training method that pushes your body to maximum effort and delivers serious improvements in cardiovascular fitness, strength, and performance in less time.

At Shred415, our class format blends both. Whether you’re walking, jogging, or pushing your pace on the treads, you’ll experience HIIT-style intervals and SIT-inspired intensity, all supported by strength work on the decks to keep your body balanced.

At Shred415, our full out effort is about reaching your max to push your limits, whether you’re walking, jogging, or running. We are an inclusive community, and we understand that reaching your full potential means pushing yourself to your personal best, not just sprinting.

How is SIT different from HIIT?

The difference between HIIT and SIT is all about intensity and recovery.

HIIT pushes you to around 70 to 90 percent of your maximum effort for 30 seconds to a few minutes, followed by short recovery periods.

SIT, which we view through our Push Interval Training approach, requires near-max or max effort, typically 90 to 100 percent, for a shorter duration, followed by a longer rest. It’s about finding your full-out push, not someone else’s.

Because SIT demands more from your body, it’s typically done less frequently, about one to two times a week, while HIIT can be repeated more regularly. At Shred415, our instructors guide you through both styles during each class so you can find your pace, challenge yourself, and recover effectively.

What is the DIT method for weight loss?

DIT, or diet-induced thermogenesis, refers to the energy your body uses to digest and process food. When paired with HIIT or SIT workouts, your body uses even more energy, increasing total calorie burn throughout the day.

According to Dr. Stacy Sims, combining high-intensity training with strength work not only supports lean muscle development but also increases EPOC (excess post-exercise oxygen consumption), the effect that keeps your metabolism elevated after the workout ends.

At Shred415, we structure every class to boost both your muscular and metabolic performance. The combination of cardio on the treads and resistance training on the decks is a proven approach for long-term results.

Are there benefits specific to women?

Yes. While HIIT and SIT benefit everyone, research shows that women in particular experience improved hormonal balance, enhanced energy regulation, and greater resistance to age-related fitness decline when using this type of training.

That said, Shred415 classes are built to benefit all bodies. Whether your goal is improved VO₂ max, body composition, strength, or cognitive focus, high-intensity intervals paired with resistance training offer the structure you need to succeed.

Want to learn more about cardio capacity? Check out our blog on how to boost your VO₂ max.

What if I don’t want to sprint?

You don’t have to sprint to experience the benefits of SIT. The essence of Push Interval Training is about effort relative to your fitness level. For some, that’s a walk at an incline. For others, it’s a jog or run. The idea behind SIT isn’t about speed; it’s about maximizing your personal effort.

Our instructors encourage Shredders to move at a pace that challenges without overwhelming. The treads are your lane, and you’re in control. Whether you’re building speed, maintaining a steady effort, or focusing on consistency, what matters most is that you push yourself toward your potential.

Remember: SIT at Shred415 is about pushing harder, not necessarily moving faster.

Why are HIIT and SIT so effective?

Both training styles are time-efficient, science-backed, and designed to help you get stronger, faster, and more resilient. Healthline reports that HIIT improves heart health, metabolic function, and muscle tone, all within shorter workouts.

When combined with strength training, HIIT and SIT (our Push Interval Training) also support better coordination, improved endurance, and mental clarity. That’s why Shred415 integrates both seamlessly into every class. You’re not just working hard; you’re training with purpose.

Train Smart. Move Strong. Shred More.

Whether you’re working to boost endurance, increase strength, or simply get more from your workout in less time, HIIT and SIT are proven to help. At Shred415, we make these training styles inclusive and effective for every fitness level.

Our combination of tread intervals and strength blocks creates a balanced, high-intensity experience designed to help you push, not punish, your body.

Ready to train smarter and feel stronger? Find your nearest Shred415 studio and book your next class today.