Written by Margaret (Maggie) Prosser, BS, CPT

Building workout routines without a personal trainer or expert can be tricky, especially for weight loss. You can choose from resistance training, plyometrics, cardiovascular endurance, yoga, and plenty of other styles. In the ever-evolving landscape of fitness trends and techniques, two methods have risen to prominence: High-Intensity Interval Training (HIIT) and Low-Intensity Steady State (LISS) workouts. Both promise significant health benefits, yet they couldn't be more different in approach and execution. As individuals seek to optimize their exercise routines for efficiency and effectiveness, the debate between HIIT and LISS intensifies.

The Basics

Any type of movement is going to help you burn calories, but the purpose of this blog post is to help you understand what the most efficient type of movement is for your weight loss goals. 

HIIT, characterized by short bursts of intense exercise followed by brief rest periods, has garnered widespread acclaim for its ability to torch calories and improve cardiovascular health in minimal time. Popular group workout chains like Orangetheory and F45 are examples of HIIT workout programs. Conversely, LISS workouts advocate for a sustained, lower-intensity effort over an extended period, promoting endurance and fat oxidation. LISS workouts include swimming, brisk walking, jogging, and cycling.  

LISS training primarily utilizes fat as a fuel source during exercise, making it an effective method for burning calories and promoting fat loss, but does little to promote lean body mass. Increased lean muscle mass burns more calories while at rest than fat mass. While HIIT may burn more calories per minute, LISS training can be sustained for longer durations.  

HIIT workouts involve short bursts of intense exercise followed by periods of rest or lower intensity activity. This alternating pattern boosts calorie expenditure both during and after exercise, leading to greater overall calorie burn compared to steady-state cardio.

Whether you burn more fat or carbs, the numbers that matter are your total energy expenditure compared to what you are taking in. An energy deficit will ultimately lead to weight loss.

How does your body adapt to exercise over time?

By aerobically training your body you build your aerobic capacity and endurance. Your body becomes more efficient at transporting oxygen and breaking down carbohydrates, proteins, and fats.  

When you engage in regular exercise, your body undergoes various adaptations to become more efficient and capable of handling the physical demands placed upon it. These adaptations occur at multiple levels, including cardiovascular, respiratory, muscular, and metabolic systems. 

What is the recommended amount of physical activity? 

The amount of exercise per week you should complete depends on your goals. Your weekly total can be any form of exercise. The Center for Disease Control and Prevention (CDC) urges people to get at least 150 minutes per week of low-to-moderate-intensity physical activity.

Final Thoughts

Both HIIT and LISS have their respective benefits. I believe they both can fit into a weekly exercise routine. Not every day has to be your “all out” and not every day has to be leisurely strolls.  

Choose things that feel good for your body. Your workout routine gets to be yours! Basic movements like walking and body weight squats can do great things for your body if you stay consistent. HIIT workouts may decrease weight quicker because it builds but lean muscle mass helps you burn more calories post-exercise while at rest. Encourage yourself to mindfully move at least once per day.  

References

Sutton BG. NASM Essentials of Personal Training. Jones & Bartlett; 2022.  

Karpinski C, Rosenbloom CA. Sports Nutrition: A Handbook for Professionals. Academy of Nutrition and Dietetics; 2017. 

Walking for exercise. Harvard T. H. Chan School of Public Health. October 26, 2023. Accessed February 6, 2024. 

Fetters K. Why you might need to do more low-intensity steady-state (LISS) cardio. October 16, 2020. Accessed February 6, 2024.  

Walking. Centers for Disease Control and Prevention. June 3, 2022. Accessed February 7, 2024.  

Foster C, Farland CV, Guidotti F, et al. The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity. J Sports Sci Med. 2015;14(4):747-755. Published 2015 Nov 24.