Navika Mittal
Edited by Lily Galapon
Published 3/12/2024
The effects of stress are well known: impaired immune function and increased susceptibility to infectious diseases. However, what many people don’t know are the intricate nervous processes that lead to such a “stressful” response.
A biological response to external situations, stress starts its journey in the brain’s command center, the hypothalamus, aptly named the “master of master gland”, which perceives the signal and generates a stress response. This signal makes its way to the pituitary gland, which releases the adrenocorticotropic hormone (ACTH) and carries the hormone to its target site- the adrenal gland. This is where the tangible response to stress actually begins. The release of epinephrine, or adrenaline, from the adrenal gland stimulates a variety of responses in the body including increased heartbeat and breathing rate. In addition, epinephrine triggers the release of blood sugar (glucose) and fats from temporary storage sites in the body. These nutrients flood into the bloodstream, supplying energy to all parts of the body.
As the initial surge of epinephrine subsides, the hypothalamus activates the second component of the stress response system — known as the HPA axis. This network consists of the hypothalamus, the pituitary gland, and the adrenal glands.
The HPA axis relies on a series of hormonal signals to keep the sympathetic nervous system — the “trigger” — pressed down. If the brain continues to perceive a situation as dangerous, the level of cortisol, a steroid hormone released by the adrenal gland, in the bloodstream remains high, keeping the body alert and active. When the threat passes, cortisol levels fall. The parasympathetic nervous system — the "brake" — then dampens the stress response.
Understanding this intricate process unveils the duality of stress. Short-term acute stress can enhance memory and fortify relationships, offering positive outcomes. However, chronic stress, characterized by prolonged cortisol release, poses serious threats to mental and physical health, leading to issues like anxiety and depression.
Researchers, armed with this knowledge, can distinguish between beneficial and harmful stressors, paving the way for innovative solutions. For example, Dr. Herbert Benson, director emeritus of the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital, suggests that relaxation techniques and physical activity can help relieve stress by deepening breathing as well as alleviating muscle tension, all of which helps reduce the buildup of high levels of cortisol in the bloodstream, thereby lessening chronic stress.
Beyond the nervous advantage of understanding these processes corresponding to environmental stresses, their extensive knowledge sheds light on other metabolic processes impacted by high levels of cortisol. For instance, one rampant ailment associated with high glucose levels called diabetes, can get exacerbated by sustained cortisol release. Though cortisol doesn’t directly cause diabetes, this stress hormone can inhibit insulin producing cells in the pancreas from working properly, reducing the amount of insulin they make.
In delving into the science behind stress, we not only empower ourselves to respond appropriately but also open doors to inventive mechanisms for alleviating chronic effects. As we navigate the intricate pathways of our nervous system's response to stress, we gain insights that extend beyond immediate challenges, impacting our overall well-being.
References
(2020, July 29). Stress and the Brain. Let’s Talk Science.
(2020, July 6). Understanding the Stress Response. Harvard Health Publishing.
Kumar, A. Rinwa, P. Kaur, G. Machawal, L. (2013, April-June). Stress: Neurobiology, consequences and management. National Library of Medicine.
Comments