The hypothalamus occupies little real estate in the brain, but it houses nuclei critical to many of the body’s regulatory functions. Situated just beneath the thalamus, it keeps the body in homeostasis by controlling the sleep-wake cycle, body temperature, hunger and thirst, sex drive, fluid balance, emotions, blood pressure, and heart rate (Johnson 2018).
The hypothalamus seamlessly links the nervous system to the endocrine system. As the body’s built-in alarm, it monitors and receives information from all parts of the body, then responds when needed by triggering the release of hormones though the pituitary gland (Sargis 2015).
Here are some additional facts about the hypothalamus:
- The hypothalamus composes only 2% of the brain’s volume and is roughly the size of an almond (Lechan & Toni 2016; Sargis 2015).
- When the body experiences stress, the hypothalamus receives a distress signal from the amygdala and activates the sympathetic nervous system. The hypothalamus then sends signals to the adrenal glands to trigger release of adrenaline into the bloodstream (Harvard Health Publishing 2018).
- As long as danger is present, the hypothalamus helps to keep the body on high alert by releasing corticotropin-release hormone (CRH). CRH stimulates the pituitary gland to discharge adrenocorticotropic hormone, which prompts the adrenal glands to release cortisol. This networking between the hypothalamus, pituitary gland and adrenal glands is known as the HPA axis (Harvard Health Publishing 2018).
- A diet high in saturated fats can alter how the hypothalamus regulates hunger and energy expenditure (Johnson 2018).
- A healthy hypothalamus is supported by a diet with foods high in omega-3 content (e.g., fish, walnuts, flax seeds and leafy vegetables), as well as vitamin-rich fruits and veggies, vitamin C, and B vitamins (Johnson 2018).
- Regular exercise has been shown to improve hypothalamic regulation of the sleep-wake cycle, energy balance and hormonal stress responses (Morgan, Corrigan & Baune 2015).
- The hypothalamus monitors core body temperature through nerve endings in the skin and through blood flow in the brain. When body temperature is too high, the hypothalamus causes blood vessels to dilate, releasing heat from the skin, and increases the rate of perspiration. When body temperature is too low, the hypothalamus preserves heat by initiating the contraction of blood vessels; it also produces heat by triggering shivers in the body (Ackerman 1992).
Ackerman, S. 1992. Major structures and functions of the brain. In Discovering the Brain. Washington, D.C.: The National Academies Press.
Harvard Health Publishing. 2018. Understanding the stress response. Harvard Medical School. Accessed Jan. 16, 2019: health.harvard.edu/staying-healthy/understanding-the-stress-response.
Johnson, J. 2018. What does the hypothalamus do? Medical News Today. Accessed Jan. 16, 2019: medicalnewstoday.com/articles/312628.php.
Lechan, R.M., & Toni, R. 2016. Functional anatomy of the hypothalamus and pituitary. Endotext. Accessed Jan. 16, 2019: ncbi.nlm.nih.gov/books/NBK279126.
Morgan, J.A., Corrigan, F., & Baune, B.T. 2015. Effects of physical exercise on central nervous system functions: A review of brain region specific adaptations. Journal of Molecular Psychiatry, 3 (3).
Sargis, R.M. 2015. An overview of the hypothalamus. EndocrineWeb. Accessed Jan. 16, 2019: endocrineweb.com/endocrinology/overview-hypothalamus.