Metabolic Stress: Definition, Causes And Consequences

Does the concept of metabolic stress sound familiar? Do you relate it to exercise? This concept refers to an organic process and, at the same time, to a factor that allows you to gain muscle mass (ie, increase muscle size). Thus, it  is a process that leads to muscle hypertrophy.

Muscle hypertrophy is the growth of the muscle, that is, the increase in its size, the number of myofibrils (consisting of actin and myosin filaments) that make up the muscle, or both variables. But what else do we know about metabolic stress? Why does it occur and what are its consequences? Is it enough to increase muscle mass? Can we use other processes?

Metabolic stress and muscle hypertrophy

As we saw in the introduction, metabolic stress  is an organic process that facilitates muscle hypertrophy. We could say that hypertrophy is what bodybuilders or people working to increase their muscle mass are looking for. In summary, this effect can be achieved through:

• Muscle damage.
• Metabolic stress.
• Mechanical tension.

Mechanical tension causes muscle damage and an inflammatory response, which would potentiate the release of muscle growth factors. Thus, the muscle would increase.

On the other hand, according to studies, the maximum gain in muscle mass is achieved through metabolic stress without loss of mechanical tension.

How does metabolic stress arise?

Metabolic stress appears when we increase the workload of a muscle or a certain group of muscles. This causes a progressive increase in muscle growth.

At a chemical level…

That is, we charge the muscle and generate a process called anaerobic glycolysis, which produces adenosine triphosphate (ATP). ATP is the energy needed to train. This process  is what allows us to obtain the energy  needed to perform muscle contractions from glucose molecules, in a state of oxygen deprivation or insufficiency.

Why does all this happen? Because the speed at which we need that energy is greater than the rate at which glucose is oxidized with oxygen, so it’s a fundamentally anaerobic process.

The accumulation of metabolites

Specifically, the metabolic stress we attribute to exercise  appears as a consequence of the accumulation of metabolites. Metabolites are compounds produced by the breakdown of nutrients.

Its function is to provide the body with the kind of energy it needs, especially during resistance training. All of this would cause the muscle hypertrophy response.

The main metabolite that accumulates due to the metabolic stress process is lactate, a glucose metabolite produced by the body’s tissues under conditions of insufficient oxygen supply. Other metabolites found in this process are: phosphate, hydrogen and the glucose metabolite (anaerobic glycolysis), among others.

Consequences

What happens when these products accumulate in the body? According to a study by Takarada et al. (2000), this could increase the secretion of several anabolic hormones. Anabolic hormones are: testosterone, somatotropin or growth hormone (ST or GH) and insulin.

On the other hand, according to the study by Ebbeling et al. (1989), the increase in waste products together with a deficiency of energy substrates (ATP) can cause muscle damage.

The importance of doing reps

One of the recurrent practices of athletes in their training, and especially of bodybuilders, is the performance of repetitions in their exercises, in addition to maintaining an intense level of training. But what happens when we train at very intense levels? This oxygen demand exceeds the supply.

In fact, the lack of oxygen, also called hypoxia, in certain muscle cells is believed to be a key factor in explaining why certain exercise repetition intervals during training lead to increased muscle growth or muscle hypertrophy.

Therefore,  doing repetitions during the exercises, as well as reducing the intervals (to a few minutes) can be interesting  if we want the accumulation of metabolites to be much greater and, consequently, the anabolic response to be too. Thus, the hypertrophy achieved would also be greater.

Final Thoughts on Metabolic Stress

As we have seen,  when it comes to gaining muscle mass or achieving muscle hypertrophy, not only metabolic stress is used, but other processes as well. This includes exerting muscle tension and causing muscle damage intense enough to stimulate muscle growth.

Metabolic stress is an organic process that would explain, in part, why muscle size increases. In this article, we were able to learn a little more about how this process works, but if you want to train in the healthiest and most effective way possible, it’s best to look for a professional who  specializes in the subject.