There are many reasons why people add amino acid supplements to their fitness routine. As a mid-workout supplement, they can maintain energy levels and reduce fatigue. As a post-workout supplement, amino acids aid in body’s recovery process and reducing muscle soreness. Whatever your personal health and fitness goals, amino acids can be a valuable tool for success.
What Causes Muscle Fatigue During Exercise?
Fatigue – that full-body feeling of low energy that makes you sigh when your routine is over. While it’s easy to understand how moving around for an hour or more and pushing your body to its limits can use up much of the body’s energy, but why does it feel like you have spent all your energy by the end of your training?
In your arms and legs, muscle fatigue is the result of both a lack of fuel – in the form of glycogen – and damage to the muscle tissue brought on by stress and catabolism. This damage is repaired through muscle protein synthesis, and glycogen is restored by consuming carbs, but both processes take time.
The other source of muscle fatigue is the buildup of a particular neurotransmitter in the brain: serotonin. This buildup is the result of your muscles using up the branched-chain amino acids (BCAAs) in your bloodstream, which typically block some of the access to the brain via the blood-brain barrier. Without those BCAAs, tryptophan can enter the brain in greater amounts, where it’s converted into serotonin.
How Branched-Chain Amino Acids Help Fight Fatigue
As mentioned above, most of the muscle fatigue, or central fatigue, experienced during a workout is the result of a lack of BCAAs in the bloodstream. This makes BCAAs an important part of any effort to reduce fatigue as you work out. By adding these amino acids to your workout routine, you can restore the levels in your bloodstream, which reduces a main source of exercise-related fatigue.
However, branched-chain amino acids can also have benefits for the muscles themselves. All three BCAAs – leucine, isoleucine, and valine – can be oxidized in the muscles, a process that generates energy when your glycogen stores run out. By serving as an alternative fuel source, BCAAs help ensure your muscles can continue performing in peak condition longer.
There are many products to help boost energy during a workout. These products can be effective at providing a jolt of energy, but they often come with side effects, such as jitters, nervousness, anxiety, and difficulty focusing. Takin amino acids should not result in these side effects and the energy they provide does not lead to a crash.
In addition, there was another source of muscle fatigue noted above – namely, the damage to muscle tissue – that BCAAs can help with as well. Because BCAAs can supply the body with energy, it saves the body from having to break down muscle tissue for fuel, preventing much of the damage that would otherwise occur.
Some research1 even indicates that these amino acids can protect the muscles. Valine, one of the BCAAs, is believed to have muscle-protecting powers, as does a metabolite of leucine. The compound beta-hydroxy-beta-methylbutyrate, or HMB, has an ability to boost protein synthesis (an ability shared by leucine) as well as “inhibit protein degradation,” in the words2 of one researcher.