Human Stress and MSD’s
Oooh! I’m very excited to share a new article we received from Leslie Henley, one of our Safety Concepts Subscribers. Les has researched the links between Human Stress and MSD’s. As the article is full of indepth information, I’ve had to cut it into segments and will add the following section the following week with links to the previous segments. So please keep visiting the site – you’ll find Les’ article very interesting.
Leslie has a Bachelor of Commerce – Employment Relations, has been a self-employed Management Systems Consultant and then gradually evolved to focus solely on OHS. Les has been an OHS Consultant and Auditor, and his current role involves both OHS and Workers Compensation/RTW duties. He has experience consulting to a wide range of industries from open cut mining/quarrying, through to forestry and manufacturing, transport and warehousing to aged and community care and the commercial/financial sector.
Leslie has a passion to promote OHS because he believes Australia needs to ‘do it better’ to protect our great quality of life. Thank you Les. 🙂
An Investigation Into The Links Between Human Stress Factors And Musculo Skeletal Disorders (MSDs)
Human Response To Stress (perceived threats)
Fight or flight Syndrome:
The human body is pre-programmed to deal with perceived threats by what is termed the ‘fight or flight syndrome’. During periods of perceived threats the human body undergoes a range of internal changes that are aimed at assisting the body to either stand and fight a threat or to run away from a threat.
These changes are aimed at providing significant blood supply, hence nutrients to and waste removal from the large muscles of the legs and arms.
These changes are brought about by the production of various chemicals by certain glands, including the adrenal gland. These chemicals target various structures and systems of the body to bring about changes that allow for this increased blood supply to the larger muscles.
Due to the fact that the circulatory system of the human body is a ‘closed system’ ie. there is a limit to its fluid content, it stands to reason that to increase the blood supply to some muscles there must be a resultant reduction of blood supply to other muscles.
There must also be changes to other systems that work in conjunction with the circulatory system to assist with the increased need for nutrients and oxygen, hence respiration and heart rate are also affected by the chemical changes.
The changes fall into three basic areas as follows:
- Central Nervous Systems changes
The central nervous system contains the majority of the nervous system, and consists of the brain and the spinal cord. Together with the peripheral nervous system, it has a fundamental role in the control of behaviour. The six senses provide information input with regard to the environment and thought processes include decision making about that information. It is through this process, of input and decision making, that threats are perceived and responses are established, including the response of ‘fight or flight’ and the resulting preparation of the body to do so.Following the identification of a threat the autonomic nervous system responds by signalling various glands and other organs to prepare the body for the fight or flight response.
- Autonomic Nervous Systems changes
The autonomic nervous system is a central part of the human nervous system that humans are not able to consciously regulate. It is the primary source of control for functions such as heart rate, blood pressure, respiration and digestion. Several changes experienced during periods of stress include:Arterio/vascular activities: blood vessels in the larger muscles expand to allow higher blood flow rates whilst blood vessels in the other muscles, not required for ‘fight or flight’, are constricted to reduce blood flow to them.
Reticular formation activities: “the reticular formation is a part of the brain that is an important regulator in the autonomic nervous system for such processes as respiration rate, heart rate and gastrointestinal activity. It also plays an important role in sleep and consciousness as well as modulation of pain. The reticular formation not only appears to control physical behaviors such as sleep but also has been shown to play a major role in alertness, fatigue, and motivation to perform various activities.” (Wikipedia)
- Immune System Activities
The threat of wounds and infection causes the immune system to establish an increased level of chemical response in preparation for fighting such infections. This involves the release of a group of chemicals called cytokines, some of which are inflammatory to the cells they affect.
It is important to note that, based on a variety of sources such as personal experience and shared information each individual will process information and make decisions about given situations differently. Hence the term ‘perceived threat’ must be recognised as being perceived by the individual.
Something that one person may have experienced and learned to cope with may not subsequently be perceived by that person as a threat. But if another person has not had a similar experience or has not successfully coped with a similar experience they may perceive it to be a threat. This means that different people may experience different responses to the same set of situational information.
