News No Comments 3 May 2018


In a previous article we analysed the physiology of muscle contraction, the basic principle to know and understand how the body reacts to a load, how muscle fibres behave under stress and how they are stimulated, activated and exhausted in reality. The biologic machine is anyway a complex set of factors and processes that are not just “mechanical”. On the road to a better body structure, we cannot not know the various types of stress, since training itself is a stress administered voluntarily to bring about a positive adjustment. To understand how much, when and how to induce it, we need to know the theory and general laws at its base. Understanding the principles will allow us to understand how we choose in practice certain levels of training intensity, volume and frequency in the routines and programs we propose in our following articles. So?  Let’s go!

Stress, the pandemic of the new millennium

There are various types of stress: mechanical, organic, psychological-social and stress caused by external agents. All types of stress share precise rules, codified in what is called General Adaptation Syndrome (GAS).

For explanation’s sake, GAS can be divided into three phases:

  • Phase 1 (acute response): The body reacts to the stimulus
  • Phase 2 (resistance): The body tries to compensate and return to normality
  • Phase 3 (exhaustion): Phase two cannot be completed, exhaustion is reached.

With phase 3 we can find ourselves in two situations: one in which we are in front of an acute stress (after a short resistance phase, if the stress is not repeated, the body goes back to a “normal” situation) and one where the body has to face chronic stress, sometimes due to multiple factors, where the resistance phase can last hours, days or years. It may not be possible to go back to normality and chronic exhaustion may be the result.

Hormonal and nervous implications for the various phases

  • Phase 1: In this first phase, called the “alarm” phase, the body undertakes to recall all the strength and energy to handle the stress in the best way possible. The main internal reaction is the production of adrenaline (catecholamine), with the consequent increase in heart rate: the body prepares to respond with attack and flight. In fact, the hypothalamus is the star in this first phase. The hypothalamus acts by secreting cortisol, adrenaline and noradrenaline (increase equal to even 10 times the norm), and producing beta-endorphins that, raising the pain threshold allow withstanding traumas and efforts better through the sympathetic nervous system.
  • Phase 2: This is the most important moment, when our body adapts to the new circumstances and tries to resist until the stressing element disappears. In this resistance phase, there is an overproduction of cortisol causing a weakening of the immune defences, and even their suppression: at the start this causes no problem, but during the long chronic stress period it makes it easier for viral and bacterial diseases to develop.
  • Phase 3: This is the stress final stage and generally takes place when the body realizes the danger has passed or when the strength is about to run out. When the resistance phase ends, two are the cases: the strength is not totally exhausted and the person feels the exhaustion phase as a weakness and a relaxing, beneficial torpor, or the resistance phase has lasted too long and the exhaustion is due to the complete lack of energy, with long and debilitating (even depressive) recovery periods. Biochemically speaking, we have a sudden drop in adrenal hormones (adrenaline, noradrenaline and cortisol) and a quick decrease in energy reserves. Basically, we are facing a depressive action opposite to resistance, that will tend to bring the body back to the condition preceding the stress and therefore in balance (the calming parasympathetic system replaces the sympathetic system). Very often, when the subject becomes stress-dependent, living very prolonged resistance phases, he/she can feel the urgent need to use sedatives (like smoke or alcohol).

The various types of stress:

Mechanical or physical stress: stress is defined as mechanical when the body is exposed to a form of mechanical strain. Weight training, a long and intense cardiovascular session, physical work (bricklaying, porterage), a wound, sprain or fracture can all be mechanical stress (the last ones can also be organic stress).

Organic stress: stress is defined as organic when an illness is in progress, when we have a fever, an organ (see liver, kidneys, pancreas, etc.) or tissue (e.g. tendinitis) is suffering, when there is an allergic response, when acute or chronic inflammations develop (also due to food or drug intolerances), etc. We talk about organic stresswhen we are convalescing after an accident and the body has initiated a repairing mechanism (severe muscle lysis, wounds, fractures), slimming (over a certain threshold), insufficient rest.

Oxidative stress: is a pathological condition caused by the break of the physiological balance, in a living body, between the production and elimination of oxidant chemical species by anti-oxidant defence systems.

Psychological-social stress: Work, family, connected with financial or social worries, traumas, bereavements, emotional needs, etc.

Stress caused by external agents: Heat, cold, lack of food, stimulant excess, etc.

Even if the compensations that the body initiates during phases 1 and 2 of the GAS are specific to the stimulus, the overall result is a reduced ability of the body to react effectively to other stress sources, in other words it is as if they added to each other.

Slimming as a source of stress

Since slimming (organic stress) is an important but inevitable stressor during this phase, because connected with a calorie restriction (stress from an external agent) or an increase in training volume-frequency-intensity (mechanical stress), it is very important to balance the stimulus-recovery ratio correctly. Since it is difficult (at least in the short term) to intervene on some stressors (see financial situation, family disputes, work, etc.), we must intervene on what we can more easily control, therefore training, diet and supplementation.

In practice ...

  • Avoid training or techniques that may cause muscle lysis: recovery from this training is normally slower, and tissue repair is stressing and costly. This makes it particularly unsuitable to conditions of calorie deficit and increased activity.
  • Do not exaggerate with stimulants: if on the one side stimulants can help us a lot with slimming, we must handle them with care. Their abuse is connected to hypercortisolemia, nervous fatigue and reduced perception of overreaching symptoms (with increased overtraining risk). We recommend you find the right dosage for your needs, plan break periods and assess your personal tolerability.
  • Avoid linear calorie restrictions: if the calorie restriction lasts too long, mechanisms will be activated so that (without talking technical) you will find yourselves thinner and fatter. Break periods or UP&DOWN strategies guarantee you lose more fat and preserve muscles more.
  • Avoid extreme dietary approaches: a more “extreme” very low carb or very low fat approach is good for recompose but not real cut periods. Even if effective, they cause the body to go into an alarm condition, forcing it to adapt. If the sum of the stressors is high, the exhaustion phase is just round the corner.

Author: Mattia Lorenzini
Personal trainer, expert in sports nutrition and author of the informative project CorporeSano – Food&Training System (




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