HIIT vs. HIRT: Why Strength Training Should Be the Core of Your Workouts
I’ve talked a lot about High-Intensity Interval Training (HIIT) for its incredible brain and nervous system benefits. It’s quick, effective, and has a profound impact on neuroplasticity and stress resilience. But when it comes to building lasting strength, supporting metabolic health, and creating a foundation for long-term resilience, High-Intensity Resistance Training (HIRT) is the real star of the show.
Most of my workouts center around HIRT, and for good reason. It offers a unique blend of physical, cognitive, and nervous system benefits that go beyond what HIIT alone can achieve. Let’s dive into what makes each method unique, how they compare, and why HIRT should take center stage in your routine.
The Basics of HIIT
By now, most people are familiar with HIIT. These workouts alternate short bursts of high-intensity effort—like sprints or cycling at max effort—with periods of rest or active recovery. A classic example might be 20 seconds of all-out effort followed by 40 seconds of light movement, repeated for 15–30 minutes. I’ve talked about this in the blog previously, using Interval Training to Regulate the Autonomous Nervous System and the benefits of stacking Interval Training and Breathwork.
HIIT has become a go-to for its efficiency and cardiovascular benefits. Studies show it can improve VO2 max, the gold standard for aerobic fitness, in less time than traditional steady-state cardio. It also stimulates brain-derived neurotrophic factor (BDNF), a protein that enhances memory, learning, and mood, while training the autonomic nervous system (ANS) to handle stress more effectively.
However, HIIT isn’t without its downsides. Its intensity can put stress on joints and muscles, and when overdone, it increases the risk of burnout. It’s a fantastic tool, but one that works best in moderation—especially if strength and longevity are your goals.
Enter HIRT: The Power of Strength
While HIIT is about explosive energy and rapid bursts, High-Intensity Resistance Training (HIRT) brings a different, yet equally powerful, approach. HIRT focuses on strength, stability, and muscle development through high-intensity compound lifts performed with minimal rest. These are not isolated movements like bicep curls or leg extensions; instead, HIRT involves full-body exercises such as squats, deadlifts, bench presses, and overhead presses that target multiple muscle groups at once. The same principles I apply to my training with kettlebell workouts, including any variation or combination of swings, snatches, squats, cleans, presses, deadlifts, rows, and more.
In my opinion, the hard-style kettlebell snatch is the epitome of everything I discuss here. When I don’t have time or energy for a full workout, I grab a heavy bell and do snatch supersets. I’ve yet to find another movement that translates so well to all types of physical activity while simultaneously building both cardiovascular endurance and strength. I rarely go for a steady-state run, but when I do, my body doesn’t remind me of that fact until I’m 3 or 4 miles in.
Unlike traditional resistance training, which often involves long rest periods between sets to maximize strength output, HIRT blends the power of strength training with the metabolic demands of shorter recovery times. This approach creates an efficient balance between building muscle and maximizing the cardiovascular benefits of the workout. It’s a hybrid approach that addresses not only muscle growth and endurance but also endurance for the nervous system, which plays a significant role in long-term resilience and recovery.
The beauty of HIRT lies in its ability to provide a holistic workout experience that strengthens not just your muscles, but also your mind and body systems. Here’s how:
Building Strength and Muscle
HIRT’s emphasis on compound movements and high-intensity sets recruits a large number of muscle fibers, stimulating both mechanical tension and metabolic stress—the two key drivers of muscle hypertrophy. Mechanical tension refers to the force applied to muscles during lifting, while metabolic stress refers to the build-up of byproducts like lactic acid during intense effort. These forces push the body to adapt, causing muscle fibers to grow and strengthen over time.
As muscle mass increases, so does your resting metabolic rate (RMR)—the number of calories your body burns while at rest. More muscle means your body requires more energy to maintain itself, and this results in a higher daily calorie burn, even when you’re not working out. This creates a lasting effect on your metabolism, making HIRT a key factor in fat loss and long-term weight management.
Supporting Brain Health
While HIIT gets plenty of attention for its ability to boost brain-derived neurotrophic factor (BDNF), HIRT offers similar cognitive benefits, but with a unique twist. Resistance training has been shown to enhance neuroplasticity, the brain’s ability to reorganize itself by forming new neural connections. This is especially important for memory, learning, and mood regulation.
Research also highlights that strength training can help combat cognitive decline by improving cognitive function, reducing anxiety, and enhancing emotional regulation. Unlike HIIT, which can be mentally taxing due to its rapid pace, HIRT provides a grounding effect. The controlled nature of lifting weights forces you to focus on form, body mechanics, and breathing, which cultivates mindfulness and helps to combat mental fatigue.
Nervous System Resilience
One of the most underrated benefits of HIRT is its profound impact on the autonomic nervous system (ANS). Unlike HIIT, which activates the sympathetic nervous system (SNS)—the “fight or flight” response—HIRT alternates between sympathetic activation during intense lifting and parasympathetic activation during the recovery periods. This process of toggling between stress and recovery trains the nervous system to become more adaptable, resilient, and balanced.
When you lift heavy weights, your body enters a state of heightened alertness, engaging the SNS, but as you rest and recover between sets, the parasympathetic system kicks in to restore calm and bring your body back to baseline. Over time, this helps build a more resilient nervous system that can better handle both the stresses of physical activity and life’s emotional challenges. Essentially, you’re training your body to respond to stress with greater efficiency and calm, a vital skill for resilience.
Long-Term Metabolic Health
One of HIRT’s most significant advantages over HIIT is its long-term effect on metabolic health. HIRT directly impacts insulin sensitivity and glucose metabolism by increasing lean muscle mass, which plays a pivotal role in how your body processes sugar and utilizes energy. Unlike HIIT, which relies on quick bursts of energy from glycogen stores, HIRT fosters a sustainable metabolic environment, improving your body’s ability to manage blood sugar levels and reducing the risk of metabolic disorders such as insulin resistance and Type 2 diabetes.
Furthermore, HIRT is linked to increased fat oxidation during and after the workout. While HIIT is a fantastic tool for burning calories in a short amount of time, HIRT builds muscle that boosts overall metabolism, leading to a more efficient system that burns more calories even when you’re at rest. This is a more sustainable and long-term way to manage weight, enhance physical performance, and support overall metabolic health.
HIIT vs. HIRT: A Comparison
To put it simply, HIIT is like a quick burst of fireworks, while HIRT is the steady glow of a campfire. Both are valuable, but their impacts are different. HIIT focuses on speed and intensity, creating immediate cardiovascular benefits and short-term calorie burn, whereas HIRT builds strength, supports metabolic health, and provides long-term resilience.
Let’s break down their key differences and how they affect your body and mind:
Energy Systems Engaged
HIIT primarily relies on the anaerobic energy system, which uses stored glycogen for short bursts of high-intensity effort. This leads to a rapid calorie burn during the workout and can create a noticeable post-exercise oxygen consumption (EPOC) effect, where your body continues to burn calories after exercise.
HIRT, while also intense, leans on a mix of anaerobic and aerobic systems depending on the rest periods and load used. Its emphasis on building muscle shifts the focus to long-term energy expenditure, as more muscle mass means a higher basal metabolic rate (BMR).
Cardiovascular vs. Muscular Emphasis
HIIT is a cardiovascular powerhouse, improving VO2 max and overall heart health by pushing your cardiovascular system to its limits. It trains your heart to recover faster, a marker of good autonomic nervous system health.
HIRT focuses on muscular strength and endurance. While it doesn’t push the heart as hard as HIIT during the workout, it still provides significant cardiovascular benefits over time, especially when combined with compound lifts that challenge large muscle groups.
Impact on the Brain
HIIT is known for its ability to boost brain-derived neurotrophic factor (BDNF), which supports neuroplasticity, learning, and mood regulation. It’s an excellent choice for improving focus and emotional resilience.
HIRT, while often overlooked for brain health, has similar benefits. Resistance training enhances cognitive function, memory, and emotional regulation. It also improves the brain’s executive functions, like decision-making and impulse control, and reduces symptoms of anxiety and depression through hormonal regulation, including increased dopamine and endorphin production.
Autonomic Nervous System (ANS) Benefits
HIIT trains the ANS by rapidly activating the sympathetic nervous system during effort and requiring the parasympathetic system to bring the body back to baseline during recovery. Over time, this improves heart rate variability (HRV), a key marker of stress resilience.
HIRT takes a more balanced approach to the ANS. The heavy lifting stimulates the fight-or-flight response, while controlled rest periods and strength-building help stabilize the rest-and-digest state. This can create a more robust and adaptable nervous system overall, particularly for those dealing with chronic stress or trauma.
Hormonal Response
HIIT triggers a surge of stress hormones like cortisol and adrenaline, which are beneficial in small doses but can lead to burnout if overdone. It’s a great short-term stimulus but requires careful recovery management.
HIRT, on the other hand, promotes the release of anabolic hormones like testosterone and growth hormone, which are critical for muscle repair and growth. It also reduces cortisol levels over time, fostering a more balanced hormonal environment that supports long-term resilience.
Calorie Burn vs. Long-Term Metabolism
HIIT is famous for its ability to torch calories quickly, both during the session and for hours afterward, thanks to the EPOC effect. However, its benefits are largely immediate and taper off quickly without consistent effort.
HIRT takes a slower, steadier approach. While the calorie burn during a HIRT session may be lower than a HIIT session, the muscle mass you gain significantly boosts your resting metabolic rate (RMR), meaning you burn more calories around the clock.
Accessibility and Sustainability
HIIT requires a high level of effort and can be taxing on joints and muscles, making it less suitable for beginners or those with injuries. Its intensity can also make it harder to sustain over the long term without risking overtraining or burnout.
HIRT is more adaptable. It can be scaled to suit any fitness level, from beginners to advanced athletes, and its focus on strength ensures longevity. Unlike HIIT, which often has diminishing returns with overuse, HIRT builds a foundation of physical and metabolic health that only improves with consistency.
How to Structure Your Week
So, there are benefits to each approach, how do you strike the right balance? Based on both research and personal experience, I recommend making HIRT the foundation of your routine, complemented by strategic doses of HIIT. Here’s a sample breakdown:
3–4 Days of HIRT: These sessions should prioritize compound movements that target major muscle groups. For example, a full-body workout might include squats, deadlifts, pull-ups, and overhead presses. Keep rest periods short (30–90 seconds) to maintain intensity without sacrificing form.
1–2 Days of HIIT: Add short, intense cardio sessions to enhance your aerobic capacity and boost neuroplasticity. These could include sprint intervals, kettlebell circuits, or bodyweight exercises like burpees. Keep these sessions under 30 minutes.
1–2 Active Recovery Days: Recovery is non-negotiable. Activities like walking, yoga, or mobility work help reduce inflammation, support the parasympathetic nervous system, and improve overall movement quality.
HIRT Should Dominate Your Workouts
At its core, fitness should enhance your life—not just burn calories. HIRT does this by building strength, resilience, and metabolic health in ways that support not only your body but also your brain and nervous system.
While HIIT has its place, it’s HIRT that offers the long-term benefits we all need: functional strength, sustained energy, and the ability to adapt to life’s stresses. By making strength the foundation of your workouts, you’re investing in a body and mind that will serve you for years to come.
If you’re looking for a sustainable, science-backed approach to fitness, start with HIRT. Incorporate it into your week, complement it with HIIT, and don’t forget to rest. Strength, after all, isn’t just what you do in the gym—it’s how you show up for the rest of your life.