Stress Response and its Downsides

• These study notes pertain to stress and the body's response, as well as the potential for stress to cause sickness.

The Stress Response

• The core of the vertebrate stress response is built around the need for muscles to work intensely.
• Glucose, proteins, and fats are released from storage sites to fuel the muscles.
• During stress, the heart rate, blood pressure, and breathing rate increase to deliver nutrients and oxygen more rapidly.
• Long-term building projects, like digestion, growth, and reproduction, are halted during stress.
• The perception of pain can be blunted during extreme physical pain.
• Memory and sensory skills can improve during stress.
• The stress response is ideally adapted for mobilizing energy, deferring long-term projects, and sharpening cognition.

The Downsides of Stress Response

• Events can sometimes make individuals sick from stress
• Prolonged stress can lead to stress-related diseases.
• Crucial hormones are rarely depleted, but the body focuses so much on defense that education, healthcare, and social services are neglected.
• The stress response can become more damaging than the stressor itself, especially when the stress is purely psychological.
• Chronically mobilizing energy at the expense of storage can lead to fatigue and diabetes.
• Chronically activating the cardiovascular system can lead to cardiovascular disaster.
• A variety of reproductive disorders may occur with sustained stress.
• Suppressing immune function for too long increases the likelihood of succumbing to infectious diseases.
• Systems of the brain that function more cleverly during stress can also be damaged.
• Efforts to reestablish balance will eventually wear us down when faced with repeated stressors.

Two Elephants on a Seesaw Model

• This is a model of stress-related disease
• Two little kids on a seesaw show allostatic balance
• Two massive elephants representing stress hormones also show how they can balance themselves
• Enormous potential energies are consumed in balancing, instead of being able to do something more useful.
• Damage from using two elephants is from how large and lumbering they are. Wear and tear throughout the body is termed allostatic load.
• The secretion rate of hormones can return to normal, but other stress hormones are secreted.
• There are two punch lines: it is necessary to appropriately turn on the stress-response, or to turn off the stress-response to prevent damage.
• Those unable to secrete critical hormone classes are at risk of Addison's disease or Shy-Drager syndrome which can cause catastrophic failures
• Disorders of excessive stress include chronic fatigue syndrome, fibromyalgia, rheumatoid arthritis, a subtype of depression, critically ill patients, and possibly individuals with post-traumatic stress disorder.
• Repeating or failing to turn off the stress response can be damaging.

Important Qualifications

• Chronic or repeated stressors can increase ones risk of being sick
• Stressors, even if massive and repetitive, do not automatically lead to illness.
• Stress increases the risk of getting diseases that make a person sick, or the risk of defenses being overwhelmed by the disease.
• There are more explanations for individual differences why only some people wind up getting sick.
• It becomes easier to design ways to intervene in the process.
• Stressors do not always lead to stress reactions.

Glands, Gooseflesh, and Hormones

• It is surprising to be reminded how far-reaching effects can be throughout the body.
• The lines of communication is between the brain and other areas, in gaining which sites are activated and which are quieted when stressed.

Stroke, Heart Attacks, and Voodoo Death

• A cardiovascular increase is important to deliver oxygen and energy to legs while being chased by a lion

Cardiovascular Stress Response

• One must shift the heart into a higher gear
• Parasympathetic tone is turned down
• Sympathetic nervous system and glucocorticoids are activated
• Veins will get more rigid, resulting in blood blasting through the heart with more force
• Blood returns to the veins with more force
• Blood will distribute prudently throughout the body
• Arteries will lead to muscles
• Non essential body parts will lessen
• Body needs to conserve water and blood
• Kidneys are reabsorptive, hidirectional organs
• Hormones help the kidneys, regulating water balance
• The kidneys are unidirectional and cause the carrying of slooshy dead weight
• During vigilance when threatened, heart rate and blood flow slow down, and vascular resistance t increases.
• Stress signatures vary with stressor.
• The various hormones must turn off in stress-response, and the parasympathetic nervous system beings to slow down.

Chronic Stress and Cardiovascular Disease

• Altering cardiovascular functions can increase the risk of heart disease.
• Stress induced raising of Hypertension causes cardiovascular disease, and elevates blood pressure.
• The heart and blood vessels work harder from chronic stress until they wear out.
• Small vessels have to work harder to regulate blood flow
• Small vessels build a thicker muscle layer around them, becoming more rigid
• Force tends to increase blood pressure, resulting in a vicious cycle

Health Consequences

• Heart is impacted with more force over time which means there is greater impact on the heart muscle wall.
• Leads into "left ventricular hypertrophy,"
• Irregular heart beat can occur.
• After controlling for age, having left ventricular hypertrophy is the single best predictor of cardiac risk.
• Blood vessels have bifurcations, where vessels branch into smaller and smaller units, but are vulnerable to injury
• Damage occurs at branch points during repeated stress which can lead to smooth linear tears, which can result in inflammatory responses
• Cells full of fatty nutrients begin to form there, too, these are called foam cells
• During, stress the sympathetic nervous system makes blood more viscous by mobilizing energy

Atherosclerotic Plaques

• Stress promotes plaque formation by increasing damaged vessels
• Clogged vessels are prone to circulating platelets and lead to "bad" cholesterol
• Cholesterol can get trapped and aggregated in inflamed injuries
• Damaged and inflamed blood vessels is a better predictor for cardiovascular trouble
• High cholesterol can be tolerated if there is enough vascular damage,
• Plaques can form when there are healthy levels of cholesterol
• C-reactive protein (CRP) indicate injury, and can help amplify inflammation and trap bad cholesterol in aggregates for early detection to avoid heart disease
• Monkeys can have beta-blockers to prevent sympathetic activity

Other Health Issues

• Too many atherosclerotic plaques in lower body causes claudication, which hurts legs causing bypass surgeries.
• Arteries going to the hear cause horrible coronary herat diseases.
• Plagues can become mobile and tear loose and become lodged by the arteries.
• Clog up vessels trigger Myocardial Infarcts and strokes.
• Chronic stress affects blood vessels and makes each stressor more danagerous
• Coronary Arteries narrow down as heart vessels shut down to produce a shortage of nutrients causing myocardial ischemia = Terrible chest pains when stressful.
• Myocardial ischemia is where blood vessels fail to dialate in coronary arteries Brief hypertension causes the vasoconstrictive problem which can produce damage to an already atherosclerosised heart.
• The development of angina pectoris is a demonstration of how stress is extremely effective at worsening a pre-existing problem
• Silent Ischemic crises are psychological stressors for heart disease: They can trigger brief periods of stress or anxiety. The key to avoiding cardiovascular diseases is in management and protection against these stress factors.

Study notes cover the stress response and its effects on the body. It includes how the body mobilizes energy, defers long-term projects, and sharpens cognition. Prolonged stress can also lead to stress-related diseases and affect hormone levels.