Fatigue: What Is Stress?
Homoeostasis, is a mechanism within the body that keeps physiological processes functioning optimally. Stressors, are external events which essentially alter the processes in some form. For example, the weather becomes really hot and you begin to sweat. The stressor here is the heat, the homeostatic response is the body producing sweat to act to cool the body down. The human body is an amazing thing, constantly changing and adapting to the external environment to contain and preserve its internal well-being.
Hans Selye (1956) introduced the General Adaptation Syndrome (below) theory, which explained how our bodies react to stress and how it deals with it.
General adaptation syndrome (1956) introduced by Hans Selye.
Phase 1 shows homeostasis. The body is maintained in a perfect state of balance. The body then is perturbed by an external stressor and enters the alarm reaction stage. You produce numerous hormones and enzymes in response to the stress in an attempt to try and survive (short term) the stress or adapt (long term).
If the stress on the body is persistent over a prolonged period of time then the individual will enter the resistance phase (phase 2). The defence mechanisms in response to stress will be constantly elevated leading to potentially negative consequences i.e. increased blood pressure, increased heart rate, heightened anxiety and other psychological issues. As a result, the immune system may become suppressed.
As the body remains in the resistance phase, and the stress on the body isn't suppressed or removed, then there is the potential to move into the exhaustion phase (phase 3). Due to being exposed to hormone production long term (specifically cortisol and epinephrine), the body can no longer deal with these metabolic adaptations. This leads to increased susceptibility to illness and disease during this phase.
If the stress on the body is persistent over a prolonged period of time then the individual will enter the resistance phase (phase 2). The defence mechanisms in response to stress will be constantly elevated leading to potentially negative consequences i.e. increased blood pressure, increased heart rate, heightened anxiety and other psychological issues. As a result, the immune system may become suppressed.
As the body remains in the resistance phase, and the stress on the body isn't suppressed or removed, then there is the potential to move into the exhaustion phase (phase 3). Due to being exposed to hormone production long term (specifically cortisol and epinephrine), the body can no longer deal with these metabolic adaptations. This leads to increased susceptibility to illness and disease during this phase.
Phase 4, the de-compensation phase, is brought about as a result of removing or suppressing the stressor and allowing the body to return to homeostasis.
We can apply this model to training. Take pre-season for example, you've taken 6-8 weeks off training and thoroughly enjoyed the time off. You arrive to day 1 of pre-season, and unsurprisingly you see no footballs. The trusted conditioning guru's are out in force to put you through your paces. Day 1 done and you enter the alarm reaction phase. The switch from sedentary behaviour to vigourous activity has overloaded your body and now it must find a way to deal with it.
The following day you wake up sore, aching and generally hating life (and your conditioning coach more than likely), but you go about your life as normal, be it school, college, work etc.
It's Thursday night training, still no sign of footballs, must be running again. Being the warrior that you are you get on with it and say nothing, placing more (similar) stress on the body. Hello resistance phase!
This cycle continues for several days and weeks (trust me I've seen/experienced it myself), and it's a week away from the start of the season and you're run down, have the flu and your hamstring feels like guitar string. Exhaustion phase has crept up on like those last minute assignments that you forgot to do and now you're out of action for a couple of days/weeks.
It's Thursday night training, still no sign of footballs, must be running again. Being the warrior that you are you get on with it and say nothing, placing more (similar) stress on the body. Hello resistance phase!
This cycle continues for several days and weeks (trust me I've seen/experienced it myself), and it's a week away from the start of the season and you're run down, have the flu and your hamstring feels like guitar string. Exhaustion phase has crept up on like those last minute assignments that you forgot to do and now you're out of action for a couple of days/weeks.
The stress of persistent exercise and inadequate recovery has manifested itself into fatigue. There may even be other consequences of this like poor sleep quality, irritability, lack of appetite and difficulty concentrating on life's other responsibilities.
It's important to remember that acute stress is required to produce adaptations to exercise and to progress. But prolonged and chronic stress is a negative outcome. Thankfully stress can be managed effectively so it doesn't develop into fatigue.
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