High-Intensity Interval Training (HIIT) has taken the fitness world by storm as a fast way to burn more fat, get stronger in less time and improve cardiovascular health. By alternating short, explosive efforts with some rest or moderately easy intervals, HIIT can deliver in a fraction of the time what low- to moderate-intensity steady state cardio does. However, some worry. could your HIIT workouts actually be causing your muscle tissue to breakdown?
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The answer is complicated. There are many benefits to HIIT, however all depending on how you plan your workouts and what they're intended for, also regarding the personal fitness goals that each person may have, it is possible that high-intensity interval training can cause muscle catabolism rather than anabolism. Let's delve deeper into this and see how to avoid it.
How HIIT Breaks Down Muscle
Catabolism — is due to muscle breakdown: this is the state in which the body begins to break down the so-called muscular tissue for energy. A lot of things can happen during HIIT, which may make this process even worse.
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When your glycogen reserves are depleted — hard high-intensity workouts require fuels, and carbs stored in muscle as glycogen are a primary source This is because HIIT quickly burns through these stores with its intensity. Glycogen is the stored form of glucose in your muscles and liver, when you run out, your body may resort to using muscle tissue as a fuel source → not good especially if you are doing long or multiple HIIT workouts per week.
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HIIT Raises Cortisol: HIIT stimulates cortisol, the stress hormone. Although cortisol helps provide energy for stress and exercise, the catabolic nature of chronically elevated cortisol means it can break down muscle. Cortisol Promotes The Breakdown Of Muscle Proteins Into Amino Acids, For Use As Glucose And An Additional Factor Leading To Catabolism.
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Non-sufficient recovery: HIIT is incredibly taxing on your muscles, cardiovascular and nervous system. If you do not have enough time to heal your body structure, your body start overtraining and it will begin taking muscle tissue away instead working on repairing them. HIIT is a little more hardcore, so you definitely need to take enough rest and you ALSO need to eat well just in case your muscle gets burned further instead of fat.
**Why HIIT Could be Breaking Down Muscle
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Doing Too Much HIIT, Too Frequently: The more intense and frequent your HIIT sessions are, the greater risk of muscle breakdown. Our bodies are fatigued from the high-intensity of HIIT, and without rest days in between, this can lead to overtraining and muscle depletion which is a direct cause for catabolism.
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Low-Calorie / Low-Carb Diets: HIIT is also often used in combination with a very low-calorie or fad caloric restricted diets to further expedite fat loss. Even so, it can shoot you in the foot on this since you might not be eating enough protein or carbs to truly fully recover. If your body doesn't have enough energy to sustain it, it will use muscle for fuel, causing you to lose muscle, not fat.
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Not paying enough attention to strength training: HIIT is typically very cardio focused, especially when it involves movements like sprinting, cycling, and jumping. If your goal is to lose weight and the majority of your workout is therefore focused around aerobic activities, then HIIT without including some kind of resistance training for muscle building and maintenance might not be doing enough work for the preservation of muscle if you are prone to it diminishing during fat loss efforts.
How Do You Avoid Your Muscles from Breaking Down During HIIT?!
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Although it has some drawbacks when taken to the extreme, you can mitigate any potential risks by modifying your training so that muscle loss is minimal, and the benefits of HIIT are maximized:
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Integrate Strength Training — This assists in preventing muscle break down at least, so be strict about getting regular weightlifting or resistance exercises into your week More specifically, strength training support muscle building and muscled mass retention during HIIT sessionsoras well as through the duration of your weight loss program.
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Eat Right: Make sure your diet includes enough protein to help repair and rebuild the muscles. At a minimum: 1.6-2.2 grams of protein/kg body weight per day You also need to add in some carbohydrates for glycogen replenishment if you are doing long or regular HIIT workouts.
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Keep Your Workouts in Balance: Do Not Let HIIT dominate your routine. But, it is an intense and fat burning workout so overdoing can result in overtraining and muscle catabolism. I actually encourage you to combine your HIIT workouts with some moderate- or even lower-intensity days and also rest.
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Recovery: Even with a 5-minute workout, high intensity interval training takes a toll on your body and focus on recovery in between sessions. While rest days are important, recovery also includes ensuring proper sleep, hydration, and stress management as aids for muscle healing and growth.
Conclusion
HIIT is an awesome workout to improve cardiovascular fitness and burn fat, but overdoing it can cause muscle breakdown — especially if your body is not in a position to recover, be nourished, or balance. If you want to do HIIT and still benefit from muscle retention, ensure you also strength train, fuel your body properly and treat recovery as a non-negotiable.
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HIIT is powerful but if you do it too much and without programming smartly, it can start to wash away all your muscle gains.