Is cardio really getting in the way of muscle building and how to avoid it?

Cardio is very beneficial. They improveEffects of Exercise to Improve Cardiovascular Health, Reversing the Cardiac Effects of Sedentary Aging in Middle Age - A Randomized Controlled Trial: Implications For Heart Failure Prevention heart health, reduceAerobic, resistance or combined training: A systematic review and meta ‑ analysis of exercise to reduce cardiovascular risk in adults with metabolic syndrome risk of cardiovascular disease (CVD), help relieveMeta ‑ analysis: Effect of exercise, with or without dieting, on the body composition of overweight subjects extra pounds and get rid ofA systematic review and meta-analysis of the effect of aerobic vs. Resistance exercise training on visceral fat from dangerous visceral fat.

Many athletes and amateurs combine cardio and strength training in their program, and this is great: this mix helpsAerobic or Resistance Exercise, or Both, in Dieting Obese Older Adults lose weight without losing muscle mass and reducesComparative effectiveness of aerobic, resistance, and combined training on cardiovascular disease risk factors: A randomized controlled trial

the risk of CVD is even greater than just aerobic exercise. But such a system also has its disadvantage, which is very significant for athletes of strength sports and bodybuilders.

How cardio training affects strength and muscle growth

In researchInterference of strength development by simultaneously training for strength and endurance 1980, the participants were divided into three groups: in the first, people trained with weights five days a week (C), in the second - six days a week they did cardio (C), and in the third they did both those and other activities (C + TO).

K-group did not increase strength at all - only endurance. In groups C and C + K, strength indicators initially grew equally well, but in the ninth week of C + K the beginning fall behind, and by the end of the experiment, the strength training group became the absolute leader, despite the same volume loads.

Subsequent researchConcurrent training: a meta-analysis examining interference of aerobic and resistance exercises, High volume of endurance training impairs adaptations to 12 weeks of strength training in well-trained endurance athletes confirmed this effect: adding to strength cardio sessions inhibits the increase in strength and muscle size.

Over time, the term "concurrent training" was formed in the scientific community, and the decrease in performance from such exercises was called the interference effect.

Why does the interference effect occur?

Scientists still don't know exactly how cardio interferes with muscle growth. Moreover, this does not always happen: in some studiesConcurrent exercise training: do opposites distract?, Concurrent Endurance and Explosive Type Strength Training Improves Neuromuscular and Anaerobic Characteristics in Young Distance Runners, The Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals competing training did not reduce the gain in strength. There are several theories about this. Some affect the mechanisms inside cells, others - the effect of exercise on the nervous system.

Adaptations interfere with each other

Scientists have suggested that, since the body adapts differently to power and cardio loads, certain mechanisms can interfere with each other. There is a theorySirtuin 1 (SIRT1) Deacetylase Activity Is Not Required for Mitochondrial Biogenesis or Peroxisome Proliferator ‑ activated Receptor-γ Coactivator ‑ 1α (PGC ‑ 1α) Deacetylation following Endurance Exercisethat the interference effect is due to the protein sirtuin-1.

It is produced in response to energy-intensiveInterdependence of AMPK and SIRT1 for metabolic adaptation to fasting and exercise in skeletal muscle aerobic exercise and may suppressSIRT1 Negatively Regulates the Mammalian Target of Rapamycin the activity of the mTOR rapamycin target, a complex that signals increased protein synthesis after strength training.

Another possible cause is stress in the endoplasmic reticulum, an important cell organelle. When its function is impaired, it triggers a specific unfolded protein responseSignal integration in the endoplasmic reticulum unfolded protein responsewhich reduces protein synthesis and thus interferes with muscle hypertrophy. And such stress can occur, among other things, after energy-intensive exercises such as cardio sessions.

The central nervous system (CNS) gets tired

This is another explanation for the interference effect, based on the fatigue characteristics of the body. In general, exercise fatigue is divided into two types:

• Peripheral - this is when the brain sends signals for muscle fibers to contract, but some part of them cannot do this due to fatigue. As a result, the signals become larger and the body has to use fibers that did not work before. This is useful for hypertrophy: the more signals are sent to the muscle, the more fibers will receive the load as a result, and then increase in size.
• Central - this is when the brain cannot send enough signals, so most of the fibers are not used. This negatively affects performance strength trainingbecause the muscles are not getting enough stress, there is no fatigue or growth.

Endurance exercise, especially long-term exercise, causesNeural Contributions to Muscle Fatigue: From the Brain to the Muscle and Back Again fatigue of the central nervous system, and this reduces the ability to produce strength.

If you do a cardio session for 30-40 minutes before strength training, the central nervous system will fatigue and will not be able to activate muscle fibers as well as if you were training with fresh strength.

Research confirms this. Putting strength training before cardio increases strength Strength prior to endurance intra-session exercise sequence optimizes neuromuscular and cardiovascular gains in elderly men almost twice as fast as in the reverse order of classes. Also, when strength training is done before cardio, the interference effect is negligible.The Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals even in very trained people.

How to do cardio without getting in the way of building muscle

Cardio can only be removed from your program if you want to turn into a mountain of muscles in no time. If endurance is important for your sport or if you want more than impressive figurebut also a healthy heart - keep aerobic training, but keep a few points in mind.

Do an aerobic workout after strength

This does not apply to 5-10 minutes of jogging or jumping rope to warm up. Brief aerobic activity warms up the muscles well and does not tire the central nervous system, so you can leave the usual warm-up unchanged. But long cardio sessions of 30 minutes or more are better to be rescheduled. Perform them either a few hours after the power load, or in free gym days.

The more time elapses between your cardio session and strength training, the more chances that the central nervous system will have time to recover and you will be able to fully load the muscles.

Try high-intensity interval training (HIIT)

While HIIT can be hard on, short, intense exercise is much lessEffects of fatigue duration and muscle type on voluntary and evoked contractile properties, Mechanisms of fatigue differ after low- and high-force fatiguing contractions in men and women, Central and peripheral fatigue in male cyclists after 4-, 20-, and 40 ‑ km time trials load the central nervous system than long, calm cardio sessions. At the same time, intensive intervals develop enduranceEffects of moderate ‑ intensity endurance and high ‑ intensity intermittent training on anaerobic capacity and VO2maxhelp to lose weightExercise Intensity and Energy Expenditure of a Tabata Workout and improveHigh ‑ intensity interval training versus moderate ‑ intensity continuous training within cardiac rehabilitation: a systematic review and meta ‑ analysis cardiovascular health is as good or better than cardio.

Replace long runs with short HIIT sessions of 8-24 minutes: this will increaseThe Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals aerobic capacity and will not interfere with you build muscle.

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