The brain behind the balance

October 21st, 2025

Written by: Serena Chen

The cells in your body exist in a constantly changing environment. Your diet provides them with nutrients that fluctuate with each meal. Breathing involves continuous gas exchange between your cells and your bloodstream, taking in oxygen needed for energy production and removing carbon dioxide¹. And routines like sleeping and exercising impact how your cells eliminate waste, build new tissues, and clear out older cells². Your cells can even communicate with one another by responding to chemical signals from neighboring cells and releasing their own molecules and proteins³. These are just a few examples of the external and internal alterations that happen in each tissue and organ of your body. It sounds like a lot going on at once, but behind the scenes, your brain helps coordinate many of these changes – adjusting your hunger, breathing, sleeping, etc. In fact, one of your brain’s most important yet least visible jobs is coping with all these changes, keeping your body stable so that it can perform its everyday functions. It seems like an incredibly active process, yet somehow you never even need to think about it when it happens. So how does the brain pull that off?

Keeping the Body Balanced and Stable

The ability for your body’s tissues and organ systems to sustain a balanced internal state is called homeostasis⁴. Regulating homeostasis requires constant monitoring, even when you are resting or asleep. This is where the role of your brain comes in! One part of the brain that is central to maintaining homeostasis is the hypothalamus⁵. The hypothalamus is a small but powerful part of the brain that oversees key functions like body temperature, sleep, blood pressure, hunger, thirst, and energy use⁵. To do this, the hypothalamus receives chemical messages from nerve cells and organs around your body that may be undergoing change. It then reacts to this by sending its own messages back to the body about how to respond to that change.   

For example, the hypothalamus regulates body temperature by operating as the body’s thermostat⁶. This is particularly important as cells in the human body function best at 37˚C (98.6˚F)⁶. Therefore, the hypothalamus receives temperature information from nerve cells in your skin. When it is too cold outside, the hypothalamus instructs muscles to start shivering, generating heat. When it is too hot, it triggers sweat glands to produce sweat, cooling the body as the moisture evaporates⁷. But temperature is not the only thing your body has to keep balanced. There are dozens of other processes that are being balanced at any given moment. Therefore, homeostasis is tightly regulated by the brain and requires constant adjustments that keep your cells’ surroundings steady. In many ways, homeostasis is like a boat on water, constantly rocked by waves but making small corrections in its sails and speed to stay upright and on course. Steering that boat is the brain, with the hypothalamus being its captain.

Critical Messengers of Homeostasis

As you now know, the brain plays a key role in homeostasis by staying in constant conversation with the body, receiving information about the condition of its many tissues and organs and relaying information back about what needs to be done in response⁵. If homeostasis is disrupted, brain regions like the hypothalamus send messages to the parts of the body needed to bring conditions back to baseline⁵. In addition to nerve cells, these messages can be carried by hormones⁸ – special chemical molecules produced by glands around the body and the brain. Hormones travel through the bloodstream, which, like a telephone network, serves as the main communication line running through the entire brain and body.

To understand hormone-mediated homeostasis, you can think about what happens after you eat a meal. First, eating causes the level of a sugar called glucose to rise in your blood⁹. Your pancreas detects this rise and sends a hormone to signal this to your brain and liver – this hormone is insulin⁹. Your liver, muscles, and fat tissue take up glucose in response to this insulin signal and incorporate it into their energy stores, effectively lowering glucose levels in your bloodstream⁹. Meanwhile, your brain monitors this process. If blood glucose levels are still too high, your hypothalamus can send nerve signals back to your pancreas, encouraging it to release more insulin to further drive the liver’s job, until blood glucose levels return to baseline⁸. Conversely, if the opposite occurs where blood glucose levels are too low, like when you have not eaten in a while or are doing strenuous exercise, the brain senses this drop and sends different nerve signals out, directing the pancreas to release glucagon¹⁰. This hormone tells the liver to release its stored sugar into the bloodstream, until glucose levels return to baseline¹⁰. Here, the brain again acts as the command center, constantly monitoring changes and coordinating complex hormonal responses so that your body maintains a steady supply of energy – without you ever having to think about it.

The Consequences of Imbalance

The brain tightly regulates homeostasis around the body, and disruptions in these balanced conditions can lead to various diseases. For example, while brain works with the pancreas and liver to tightly regulate blood glucose levels, faltering of this fine-tuned system occurs in a disease called diabetes. Diabetes greatly affects how the body responds to insulin. In type 1 diabetes, pancreatic cells are unable to produce insulin¹¹. In type 2 diabetes, pancreatic cells may produce lower amounts of insulin or the cells that receive insulin become resistant to it, not understanding that glucose needs to be taken up, and thus leaving glucose levels high in the blood¹¹. In either case, the brain, which relies on accurate hormonal signals about energy status, receives confusing information about what is happening in the body and cannot direct glucose regulation as it usually does. This miscommunication contributes to dangerously high and low levels of blood sugar in patients with diabetes¹¹. As a result, current treatment for diabetes often involves insulin injections when a patient realizes their blood glucose is high. This treatment helps the brain, liver, muscle, and fat cells better understand the true blood glucose levels when the pancreas cannot properly inform them, restoring some balance back to this vital system, and preventing further health complications¹².

Conclusion

Homeostasis is maintained through the ongoing conversation between the brain and the body, where messages are delivered back and forth by hormones and nerve cells. Every breath, meal, movement you take is closely monitored by your brain in a larger effort to keep the body steady amid constant change and to help keep you healthy. Even when you are unaware, your brain works quietly behind the scenes, maintaining the physiological stability essential for your life.

References

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2.             Carapeto, P. V. & Aguayo-Mazzucato, C. Effects of exercise on cellular and tissue aging. Aging 13, 14522–14543 (2021).

3.             Valls, P. O. & Esposito, A. Signalling dynamics, cell decisions, and homeostatic control in health and disease. Curr. Opin. Cell Biol. 75, None (2022).

4.             Bodily Balance: Not Just a Fairy Tale. Cleveland Clinic https://my.clevelandclinic.org/health/articles/homeostasis.

5.             Williams, G. et al. The hypothalamus and the control of energy homeostasis: different circuits, different purposes. Physiol. Behav. 74, 683–701 (2001).

6.             Osilla, E. V., Marsidi, J. L., Shumway, K. R. & Sharma, S. Physiology, Temperature Regulation. in StatPearls (StatPearls Publishing, Treasure Island (FL), 2025).

7.             Tan, C. L. & Knight, Z. A. Regulation of Body Temperature by the Nervous System. Neuron 98, 31–48 (2018).

8.             Coll, A. P. & Yeo, G. S. The hypothalamus and metabolism: integrating signals to control energy and glucose homeostasis. Curr. Opin. Pharmacol. 13, 970–976 (2013).

9.             Dimitriadis, G. D., Maratou, E., Kountouri, A., Board, M. & Lambadiari, V. Regulation of Postabsorptive and Postprandial Glucose Metabolism by Insulin-Dependent and Insulin-Independent Mechanisms: An Integrative Approach. Nutrients 13, 159 (2021).

10.          Alonge, K. M., D’Alessio, D. A. & Schwartz, M. W. Brain control of blood glucose levels: implications for the pathogenesis of type 2 diabetes. Diabetologia 64, 5–14 (2021).

11.          Marissal-Arvy, N. & Moisan, M.-P. Diabetes and associated cognitive disorders: Role of the Hypothalamic-Pituitary Adrenal axis. Metab. Open 15, 100202 (2022).

12.          Kleinridders, A., Ferris, H. A., Cai, W. & Kahn, C. R. Insulin Action in Brain Regulates Systemic Metabolism and Brain Function. Diabetes 63, 2232–2243 (2014).

Cover image by Brodie on Burst.

ChatGPT-5 was used to help with rewording of some sentences, grammar, and title generation.