Bodybuilding, as you likely know, places a high value on physical appearance. This typically means developing large muscles and maintaining a low body fat percentage, both of which are achieved through heavy weight training.
On the other hand, HIIT (High-Intensity Interval Training) focuses less on progressively lifting heavier weights and more on performing high-intensity exercises in large volumes and at a fast pace. The goal is to elevate heart rate through cycles of intense effort followed by rest periods. HIIT can be done using light weights, bodyweight exercises, or traditional cardio movements.
Weight Loss: Cardio vs. Strength Training
Losing weight is fundamentally about balancing energy intake with energy expenditure. When we talk about “burning fat,” we’re referring to using the energy stored in fat cells to fuel our activities.
For individuals carrying excess fat, achieving a healthy weight can be a significant lifestyle improvement. It helps reduce the risk of obesity-related conditions such as type 2 diabetes, heart disease, and stroke.
Cardio and Fat Burning
When people begin exercising for weight loss, they often turn to cardiovascular workouts—commonly known as cardio. These exercises primarily burn calories derived from food. Combined with a healthy diet, cardio can help shift the energy balance toward weight loss.
While exercise alone may not result in substantial weight loss, it offers numerous additional health benefits. Regular cardio improves heart and lung function, increases energy levels, and supports joint health. It also helps prevent weight regain over time.
HIIT for Weight Loss
HIIT involves short, intense bursts of cardio followed by low-intensity recovery periods. Studies show HIIT can lead to greater reductions in body fat and improvements in cardiorespiratory fitness, especially among individuals with obesity.
Though cardio-based, HIIT is more time-efficient than steady-state workouts like jogging or cycling. Research shows it can reduce total fat mass by 28.5% and take up to 40% less time to achieve similar results.
“HIIT workouts also provide that coveted after-burn effect,” says Innermost personal trainer Hajnalka Balázs. “Because intense effort elevates your breathing and heart rate, your body continues to burn calories post-workout during recovery—up to 40% more energy throughout the day.”
HIIT is also highly accessible. It doesn’t require a gym membership or special equipment and can be done at home with just a mat and some space. Many workouts are available online and are often set to music, adding an element of fun.
Muscle Building and Metabolism
Fat loss isn’t the only way exercise contributes to weight management. Strength training increases muscle mass, which boosts your resting metabolic rate (RMR)—the amount of energy your body burns at rest.
Muscle is more metabolically active than fat. Researchers at the University of New Mexico found that muscle accounts for about 20% of daily calorie burn, compared to 5% for fat (in individuals with approximately 20% body fat).
Beyond fat loss, strength training provides additional health benefits such as:
Slowing age-related muscle loss
Increasing bone density
Protecting joints
It also reduces the risk of osteoporosis, osteoarthritis, and fall-related injuries. Just one hour of strength training per week can cut the risk of heart disease, cardiovascular disease, and stroke by 40% to 70%.
Strength Training for Weight Loss
Strength training includes resistance exercises such as lifting weights, using machines, or bodyweight exercises like push-ups. These activities trigger muscle protein synthesis, the natural process of muscle breakdown and repair that leads to growth.
The effectiveness of weight training in supporting weight loss is well-documented. One study found that nine months of resistance training increased RMR by 5%. Another showed it reduced body fat percentage, total fat mass, and visceral fat in healthy adults.
Major Benefits of Strength Training:
Builds Muscle: Resistance breaks down muscle tissue, prompting the body to rebuild it stronger. This process, known as hypertrophy, is amplified with heavier weights.
Boosts Metabolism and Fat Loss: More muscle means a higher basal metabolic rate. Combined with a calorie deficit, this supports fat loss.
Supports Bone Health: Weight-bearing exercises help maintain bone strength and prevent osteoporosis.
Improves Mental Health: Strength training reduces cortisol (a stress hormone) and promotes a sense of achievement.
Improves Sleep: The combination of reduced cortisol and physical fatigue contributes to better sleep quality.
Accessible and Varied: With countless exercise types, machines, and classes available, strength training suits all fitness levels and preferences.
Combination is the Key to Weight Loss
Both HIIT and strength training are proven to support healthy weight loss. The best part? You don’t have to choose just one. Alternating between them throughout the week or combining them in a single session can yield even better results.
“Incorporating weights into a HIIT session increases the intensity and combines strength and cardio,” explains fitness expert Piercy. “You might include exercises like weighted squats, dumbbell snatches, kettlebell swings, push-ups, and jumping lunges.”
By merging HIIT and resistance training, your workouts become more efficient and effective, potentially helping you achieve your weight loss and fitness goals faster. Whether performed separately or together, both approaches offer extensive benefits for overall health and well-being.
