The endocrine system and nervous system regulate nearly every process in the body—with the endocrine system handling longer-term changes and the nervous system controlling the minute-to-minute changes. Because these two systems are so intertwined, every change in one will affect the other.
Like your home’s heating and air conditioning system, feedback loops govern the vast majority of bodily activities. When it becomes too chilly in your house, the heat comes on; when it gets too hot, the air conditioning brings the temperature down.
When your blood sugar levels rise too high, your insulin levels rise as well. Insulin removes sugar from the bloodstream and returns your blood sugar levels to normal. Similarly, when your blood sugar falls below a certain level, the hormone glucagon is released to raise your blood sugar levels.
But what happens when something goes awry? When a hormone does not respond as expected? This is referred to as a hormone imbalance. It is more common than you might think, especially as we age. A little shift in one direction or the other might have far-reaching consequences. When one hormone is out of balance, it impacts other hormones. One of the most complicated systems in the human body is the endocrine system.
Consider the female sex hormones estrogen and progesterone. Before puberty, both hormone levels are low. Puberty is initiated when the hypothalamus (a part of the brain) releases gonadotropin-releasing hormone (GnRH). GnRH triggers the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gland. A synchronized release of LH and FSH regulates the menstrual cycle, the release of an egg from a follicle in the ovary, and the uterine cycle. Throughout a woman’s reproductive years, these cycles occur on a 21 to 28-day basis.
With aging, fertility wanes as the number of follicles remaining in the ovaries diminishes. Menopause occurs when a woman’s ovaries no longer have any follicles left, and estrogen production declines. The earliest phase of menopause, perimenopause, is characterized by normal estrogen levels but decreasing progesterone levels. When estrogen levels drop, symptoms develop, such as vaginal dryness and pain, hot flashes and night sweats, mood swings, brain fog, and thinning hair. These symptoms vary by women from mild to severe.
Many women are at the peak of their careers as they enter menopause. Brain fog can negatively impact their work and quality of life.
Aside from changes in the nervous system, aging, lifestyle choices, nutrition, and exercise can impact hormone levels.
Exercise lowers insulin release from the pancreas while increasing insulin sensitivity. When the level of glucose (sugar) in your bloodstream rises, the pancreas secretes insulin. Insulin binds to receptors on the cell membranes surrounding each cell as a key fits into a lock. When insulin binds to its receptor, glucose moves out of the bloodstream and into the cells, where it can be used as a source of energy.
Insulin sensitivity describes how easily insulin binds to its receptors and lowers blood sugar. If you become insensitive to insulin, your pancreas pumps more insulin into the bloodstream. No matter how much insulin is in the blood, blood sugar levels will not fall if cells are resistant to insulin’s effects. The problem is not a lack of insulin production; it is a lack of response.
Prolonged insulin resistance can cause type 2 diabetes. Besides type 2 diabetes, insulin resistance is associated with obesity, high blood pressure, and high cholesterol. Together these risk factors are called metabolic syndrome.
Signs of insulin resistance:
High blood insulin levels have been linked to inflammation, abnormal lipid profiles, heart disease, diabetes, and cancer (Fletcher, Gulanick & Lamendola, 2002). Physical activity of all kinds has been shown to increase insulin sensitivity and reduce blood insulin levels.
A single bout of exercise can increase insulin sensitivity in healthy people and people with type 2 diabetes for at least 16 hours post-exercise. Exercise can also improve your lipid profile, decreasing your risk for heart disease (Borghouts & Keizer, 2000).
With aging, there is a decline in testosterone levels in both sexes. The result is a decrease in muscle mass and an increase in truncal body fat. Resistance training can help reverse the age-related decline in testosterone levels that naturally occur (Sato et al., 2014).
A combination of aerobic and resistance exercises can help reverse the symptoms associated with a decline in growth hormone, another hormone that declines in both sexes with aging. Symptoms of decreased growth hormone include reduced muscle mass and strength, increased truncal obesity, and increased risk of metabolic syndrome (Seo et al., 2010).
Strength-building resistance exercises can help maintain muscle mass which will help you control your weight and decrease the likelihood of developing insulin resistance. Combine resistance exercises with aerobic exercises such as walking to strengthen the heart and respiratory muscles. Set small goals and gradually increase both the difficulty and length of the activity. Regular exercise can decrease stress, improve your mood, promote better sleep habits and prevent weight gain.
Our circadian rhythm, our 24-hour internal clock, regulates hormone release cycles, including ACTH and cortisol, as well as most physiological processes in the body. Light and dark cycles, mealtimes, and physical activity help the brain maintain the circadian rhythm.
Your body relies on the pineal gland to produce the hormone melatonin to maintain this 24-hour cycle. Adenosine, a byproduct of metabolism, accumulates in the brain throughout the day. When melatonin levels go up and enough adenosine has accumulated, you become sleepy. As you sleep, adenosine is metabolized and its levels decrease. Caffeine blocks adenosine receptors, promoting alertness.
Poor sleep habits stress the body. Initial symptoms of lack of sleep include fatigue, memory problems, and irritability. Since sleep replenishes chemicals used by the immune system throughout the day, a lack of sleep adversely weakens the immune system, making you more susceptible to infections.
A regular sleep cycle promotes the release of growth hormones. Growth hormone release peaks during deep sleep. Growth hormone release is reduced due to irregular sleeping habits because you often do not reach deep sleep stages.
Lack of sleep also decreases leptin levels and increases ghrelin levels, which can contribute to weight gain. Researchers have shown that lack of sleep increases cravings for calorie-dense foods high in carbohydrates (Spiegel et al., 2004). Weight gain increases the risk of diabetes, high blood pressure, and heart disease.
Most adults need 7-9 hours of sleep per day. The quality of sleep is even more important than the quantity. Try to:
The nervous system and endocrine system are inextricably linked. Two hormones whose levels are affected by stress, cortisol, and epinephrine, have a role in both the nervous and endocrine systems. Cortisol is your long-acting stress hormone. Epinephrine has a short duration of action. If your body perceives a threat, it pumps out epinephrine, so you are ready to fight or run.
Today’s lifestyle triggers these reactions, yet there is usually no genuine physical threat. Chronic stress raises cortisol levels, stores calories, and stimulates your appetite, preparing your body to fight or take flight. When the danger never materializes, these excess calories are stored in the worst possible way, as abdominal fat. Abdominal fat is linked to an increased risk of metabolic syndrome. Metabolic syndrome increases your risk for high blood pressure and heart disease.
Cortisol is involved in:
When cortisol levels are elevated for prolonged periods, side effects can include:
Consider ways to address your stress. Exercise is ideal. Try yoga, massage therapy, listening to music, journaling, breathing exercises, or meditation.
Proteins are required for tissue formation and repair, muscle building, fighting infections, and as building blocks for hormones, neurotransmitters, and enzymes. Hormones are the endocrine system’s messengers, neurotransmitters serve the same role for the nervous system, and enzymes are required for nearly every chemical reaction in the body.
Hormones are mostly made up of protein, so getting enough protein in your diet is critical. Hormones in a feedback loop control your appetite. Ghrelin is released before meals and decreases within 15-20 minutes after eating, whereas leptin levels rise after eating. Too much ghrelin release and you will be constantly hungry, which leads to weight gain.
Dietary proteins appear to be more satiating than carbohydrates. Protein consumption decreases ghrelin levels (Bowen et al., 2006). As your metabolism slows with aging, including more protein in your diet can help you cut calories without feeling hungry all the time (Belza et al., 2013).
Carbohydrates are the body’s primary energy source. Unprocessed or minimally processed whole grains, fruits, vegetables, low fat or no-fat dairy, and beans are the healthiest carbohydrates.
Avoid sugar and refined carbohydrates, particularly fructose, which has been shown to increase insulin levels and insulin resistance, especially in those with a family history of type 2 diabetes or who are overweight or obese.
Fructose is found in high-fructose corn syrup and refined table sugar in addition to its more natural forms. Other refined carbohydrates may also promote insulin resistance.
Monounsaturated and polyunsaturated fats are healthier fats to consume than saturated and trans fats. Excellent sources of fats are plant oils, avocados, butter, fatty fish, nuts, and some seeds. Choose fats high in heart-healthy omega-3 fatty acids and avoid trans fats entirely.
Consider any endocrine-stressing lifestyle habits you may have. Tobacco use, excessive alcohol consumption, vaping, exposure to environmental chemicals, or pollution can all have an impact on the endocrine and nervous systems. Chemicals that interfere with normal hormone levels are called endocrine disruptors.
Here are some common endocrine disruptors:
Be aware of endocrine disruptors and minimize your exposure. The biggest risk factor for your health is smoking. If you are a smoker, seek help in quitting.
When hormones are unbalanced and symptoms develop, you will need to consult with an endocrinologist or other specialist. After a thorough history and physical exam, an endocrinologist will probably order blood work to test your hormone levels. Medications are available to restore hormone levels or treat the symptoms caused by abnormal hormone levels.
If you have symptoms or signs of an endocrine disorder, self-treating may allow the condition to worsen. These recommendations on balancing your hormones are intended to reduce your risk for endocrine-related disorders, not to self-treat symptoms.
Supplements, herbs, and alternative treatments have been used and passed down from generation to generation. Some of these treatments improve overall health and, as a result, may benefit the endocrine system. Some have undergone testing and proven their benefits, while others have not. Each individual’s genetic predisposition and metabolism are unique. What may work for one person may not for another.
When choosing supplements and alternative treatments, research the company that manufactures the product. Verify that it meets the standards you expect. Because the FDA does not regulate supplements, each of us must assess the products for ourselves.
Medications are used to replace hormones when levels are low. Here are some examples:
Everything, whether made by a pharmaceutical company or a supplement company, has potential risks and benefits. When you meet with your healthcare provider, ask about the risks and benefits of taking a supplement or a medication.
For example, birth control pills:
After weighing the risks and benefits, you decide whether to take medication based on how you assess the risks and benefits. Each of us has a genetic predisposition to certain diseases and medical conditions, which will alter our risk and benefit profile. What makes sense for one person may not for another.
The endocrine system is a complex system of glands, hormones, and target cells. The same hormone may play a role in several physiological processes depending on the target cell.
Pituitary Gland: on the undersurface of the brain, the pituitary gland is called the master gland because it controls the functions of many other glands. The pituitary gland is connected to the hypothalamus, a part of the brain that controls body temperature, thirst, hunger, sleep, and emotions.
|Endocrine Gland||Associated Hormone||Target Organ||Effect|
|Anterior Pituitary||Growth hormone (GH)||Muscle and Bone||Promotes growth of body tissue by stimulating the liver to release insulin-like growth factor 1, stimulates fat cells to break down stored fat, increases the uptake of amino acids from the blood to build proteins, stimulates the release of glucose from the liver to provide energy for growth|
|Anterior Pituitary||Prolactin (PRL)||Breast||Promotes milk production from the mammary glands|
|Anterior Pituitary||Thyroid-Stimulating Hormone (TSH)||Thyroid gland||Stimulates thyroid hormone release from the thyroid gland|
|Anterior Pituitary||Adrenocorticotropic Hormone (ACTH)||Adrenal Gland||Promotes the release of cortisol and other glucocorticoids, which regulate metabolism and the stress response|
|Anterior Pituitary||Follicle-Stimulating Hormone (FSH)||Ovaries and Testes||Stimulates the production of the gametes, the ova (egg) and spermatozoan (sperm)|
|Anterior Pituitary||Luteinizing Hormone (LH),||Ovaries and Testes||Stimulates the production of estrogen, progesterone, and testosterone|
|Posterior Pituitary||Antidiuretic Hormone (ADH)||Kidney, sweat glands, circulatory system||Promotes retention of water by the kidneys when sodium levels are high, helps maintain water balance|
|Posterior pituitary||Oxytocin||Uterus, Mammary Glands, Brain||Promotes uterine contractions during childbirth, stimulates milk ejection for nursing, involved in maternal and partner bonding and the sexual response|
|Thyroid||Thyroxine (T4), triiodothyronine (T3)||Cells of the body||Increases metabolism, increases body temperature, increases protein synthesis, can influence libido, fertility, and other reproductive functions, and can increase the body’s sensitivity to epinephrine and norepinephrine|
|Thyroid||Calcitonin||Bone, intestines, and kidney||Reduces blood calcium levels by building bone, decreasing calcium absorption from the intestines, and increasing calcium loss in the urine|
|Parathyroid||Parathyroid Hormone (PTH)||Bone, intestines, and kidney||Increases blood calcium levels by breaking down bone, increasing calcium absorption from the intestines, and decreasing calcium loss in the urine|
|Adrenal (Cortex)||Aldosterone||Kidney, salivary glands, sweat glands||Regulates the concentration of sodium and potassium in the urine, saliva, and sweat, regulates blood pressure along with ADH|
|Adrenal (Cortex)||Cortisol, corticosterone, cortisone||Cells of the body||Breaks down stored nutrients for energy, long-term cortisol release causes the breakdown of muscle for amino acids, triglycerides into fatty acids and glycerol, and glycogen to glucose, excess fuels are stored, down-regulates the immune system|
|Adrenal (Medulla)||Epinephrine, norepinephrine||Cells of the body||Stimulates the fight-or-flight response, increases blood flow to the muscles|
|Pineal||Melatonin||Brain||Regulates sleep cycles|
|Pancreas||Insulin||Liver, adipose tissue, body cells||Lowers blood glucose levels, stimulates the liver to make glycogen from glucose, inhibits the conversion of amino acids to glucose, and stimulates body cells to take up glucose from the bloodstream|
|Pancreas||Glucagon||Liver, adipose tissue, body cells||Raises blood glucose levels, stimulates the liver to break down glycogen to glucose, to convert amino acids to glucose, breaks down fats to fatty acids and glycerol, inhibits body cells from taking up glucose from the bloodstream|
|Testes||Testosterone||Muscle, bone, adipose tissue, reproductive organs, other cells||Stimulates the development of male secondary sex characteristics and sperm production|
|Ovaries||Estrogens and Progesterones||Muscle, bone, adipose tissue, reproductive organs, other cells||Stimulate the development of female secondary sex characteristics and prepare the body for childbirth|
Other tissues in the body produce hormones in addition to their primary functions, including:
The signs and symptoms of hormone imbalance will depend on which hormone is affected, but may include:
Erectile dysfunction can be a symptom of low testosterone levels, but it can also be an early warning symptom for blood vessel problems. Speak to your doctor about your symptoms. Very effective treatment options are available, one of which is Trimix, an injectable comprising three medications that increase blood flow into the penis. Trimix is considered second-line therapy to treat erectile dysfunction in men who cannot take phosphodiesterase inhibitors, have severe side effects, or have not had successful results with oral ED medications. Based on clinical studies, the success rate for Trimix, when treating ED, is 80-95%.
The American Urological Society defines low testosterone (Low-T) as less than 300 nanograms per deciliter (ng/dl). Low testosterone levels can cause a low sex drive, decreased lean muscle, irritability, fatigue, erectile dysfunction, and depression. Whether low testosterone levels are due to medical conditions such as cancer treatment, genetic conditions, or lifestyle factors such as the aging process, many men are interested in testosterone replacement treatment programs and seek information online.
Learn More: Testosterone Replacement Therapy
The signs and symptoms of hormone imbalance will depend on which hormone is affected, but may include:
Estrogen and combination, estrogen and progesterone medications are available to ease the symptoms of menopause. Speak with your doctor to learn more about the options and evaluate your risks and benefits.
Learn More: Cognitive Symptoms in Menopause
If you are concerned that your hormones may be unbalanced, speaking with a healthcare professional to get an appropriate lab test is a next step. The endocrine system is complicated, and most lab values are lab-specific and age-specific. Your healthcare professional will recommend a lab for you, receive the results along with laboratory standards and help you interpret your results.
Invigor Medical works with a network of partner labs. These labs have met high laboratory standards and are trusted by healthcare practitioners for providing accurate results. For more information:
While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case. The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice.
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