The immune system keeps the body healthy by getting rid of foreign attackers and keeping an eye on how cells work. Keeping this natural balance is what makes it possible for the body to do its jobs as well as it can. When this balance is off, it can be bad for a person’s health.
Psychological stress is the body’s reaction to demands or events in the environment that are bigger than the person’s ability to deal with them. Stress is something everyone knows, and it tends to get worse in times of disaster and peak performance. But going over this limit could cause stress-related worry or discomfort, which can both hurt performance. The response of the endocrine system to long-term stress can cause both emotional and physical signs of distress.
When these symptoms combine with the immune system, they could do a lot of damage to the body. Because they all work together, the CNS, the immune system, and the endocrine system are all sensitive to stress. Psychoneuroimmunology is the name for this area of study.
How Stress Acts on the Immune System
When the body feels stressed, it sends out hormones that work as a “fight or flight” reaction. The hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic-adrenal-medullary (SAM) axis are the parts of the body that make these hormones. The HPA axis is controlled by cytokines and by signals from the brain to the body.
In reaction to stress, the SAM axis quickly releases epinephrine (also known as adrenaline) and norepinephrine (also known as noradrenaline). Catecholamines are a type of hormone that makes you want to fight or run away. The adrenal glands, which are above the kidneys, make epinephrine, while norepinephrine is the main stimulant of the sympathetic nervous system.
Epinephrine causes changes in the way the body works, like a faster heart rate, higher blood pressure, and more sugar in the blood. Even when you’re sleeping, norepinephrine is working hard to keep your heart beating at a steady rate. When stress causes the amount of Norepinephrine to go up, the HPA axis reacts.
Corticotropin-releasing hormone (CRH) is released by the brain. This hormone tells the pituitary gland to make adrenocorticotropic hormone (ACTH). When this hormone binds to the adrenal glands, cortisol and other glucocorticoids are made. Cortisol raises blood sugar and sends glucose to the muscles by lowering the defense system and stopping other less important things from happening.
Immune System Suppression and Health Consequences
Hormones can affect immunity by working directly on the receptors of immune cells or by changing the chemical makeup of the brain through cytokine inhibitory feedback. Hunger and sleep problems can hurt your health in a lot of ways, like making your defense system weaker. Several studies have shown that these effects on the immune system are true.
In mouse models of influenza, there is a big difference between stressed animals and controls after restraint stress. When both proinflammatory and anti-inflammatory cytokines levels went up, the body made less antiviral antibodies. The glucocorticoid receptor was turned off, which made the mice’s immune systems work normally again. This suggests that stress is a major cause of the illness.
In recent vaccine studies, a lot of attention has been paid to how stress affects the immune system. In a study about the Hepatitis B vaccine, medical students with different amounts of worry and anxiety took part. Antibody and T-cell responses to a virus were weaker in groups that were stressed. It was also shown that social support can help lessen the bad effects of changes in the immune system.
Due to the high amounts of chronic stress they face every day, caregivers are often used as a study group in the vaccine literature. Compared to the general community, caregivers had a lower response to the flu shot in terms of antibodies and T-cells that were specific to the virus. The rubella vaccine caused a similar reaction. An rise in the production of cytokines that cause inflammation has also been linked to long-term stress.
When they were tested with pneumococcal vaccines, caregivers had lower amounts of IgG antibodies than controls. In a second study, the meningitis conjugate immunization was used to confirm these results. These results show that worry makes it more likely that your body won’t respond well to vaccines and illnesses.
Another thing that stress and hormonal changes can do to the immune system is make it harder for wounds to heal. Compared to mice that weren’t restrained, those who were had wounds that healed 27% slower. By blocking the glucocorticoid receptor, this action was made less strong.
In later studies with the student and caretaker groups, a skin wound that was the same for both groups was used. When the same group of students was looked at during the break and right before finals, they healed cuts 40% more slowly right before finals. The wounds of caregivers healed 24% slower than those of healthy controls. In all cases, stress caused peripheral blood leukocytes that had been stimulated to make less IL-1 mRNA.
Stress hurts a person’s health over time and in the long run. When the body senses stress, it moves its internal resources to deal with the current threat and stops using them for things that aren’t as important. The stress reaction of the endocrine system directly stops the immune system from working.
During these times, the body’s ability to fight off diseases, heal wounds, and protect itself from vaccines could all get worse. Also, the production of pro-inflammatory cytokines goes up, which makes it more likely that long-term inflammation will damage tissues.
Blood amounts of cytokines like IL-6 have been linked to a number of diseases that can kill. Stress will be a very important thing to think about when figuring out how well a vaccine works. This is especially true given the current trend toward vaccinations as a way to prevent the most dangerous diseases, like coronavirus and the growth of different cancers. We can’t say enough about how important it is for people to learn more about how stress affects the immune system.