Stress and Diarrhea: What’s the Link?

Stress can cause diarrhea and other physical symptoms.

Stress

Stress is a natural bodily reaction to pressure or a perceived threat. A little stress can be a good thing, as it can help motivate a person, focus the mind, and improve performance. However, excessive or chronic stress can affect a person’s psychological and physical health. Chronic stress negatively impacts physical health (e.g., heart disease, weakened immunity), mental health (e.g., anxiety, depression), and behavior (e.g., overeating, isolation).

Diarrhea

Diarrhea is the medical term for loose, watery stools. It is a symptom of an underlying issue rather than a disease in itself. Some symptoms that may accompany diarrhea include abdominal pain and cramping, an urgent need to empty the bowel, and loss of bowel control. Diarrhea may be acute or chronic. Acute diarrhea lasts only 1–2 days, whereas chronic diarrhea continues for 4 or more weeks.

Globally, diarrheal diseases remain a significant health challenge, particularly in low- and middle-income countries. They are one of the leading causes of morbidity and mortality. Diarrheal diseases accounted for approximately 1.5 billion cases annually worldwide, with the highest prevalence reported in regions lacking access to safe water, sanitation, and healthcare. Diarrhea is linked to inadequate sanitation and poor hygiene.

Diarrhea is caused by infections (bacterial, viral, or parasitic), contaminated food or water, medications (e.g., antibiotics), digestive disorders (like irritable bowel syndrome or lactose intolerance), stress, and certain medical conditions.

Symptoms of Stress Diarrhea

A person suffering from stress diarrhea might experience one or more of the following symptoms: tense muscles, neck pain, headaches, feelings of fatigue, increased irritability, depression, problems sleeping, feelings of restlessness, heightened anxiety, feelings of being overwhelmed, or decreased sex drive.

Disturbed Gut-Brain Axis

Stress disrupts the communication between the brain and gut, leading to digestive symptoms. When you experience stress or anxiety, your body releases hormones like cortisol and adrenaline, which can affect the digestive system. This can lead to changes in gut motility and an increase in the speed at which food moves through your intestines, resulting in diarrhea.

When under stress, the hypothalamic-pituitary-adrenal axis is activated, leading to increased production of hormones. Stress hormones can alter the gut-brain axis, increasing intestinal permeability. This can allow bacteria, toxins, and undigested food particles to pass through the intestinal lining, which can irritate the gut and lead to diarrhea.

Stress can speed up or slow down bowel movements. For some people, this can cause diarrhea as the digestive tract becomes overly responsive or overly sensitive to stimuli under stress.

Stress can affect neurotransmitter levels such as serotonin, which play a role in gut function. Imbalances in these neurotransmitters can contribute to symptoms like diarrhea.

How Serotonin Affects Diarrhea

Serotonin plays a significant role in regulating gut function, and its levels can influence gastrointestinal symptoms like diarrhea. It is the primary neurotransmitter involved in bowel motility and intestinal secretion.

Elevated serotonin levels in the gut can lead to increased secretion of water and electrolytes into the intestinal lumen. This can cause an increase in stool frequency and watery diarrhea, especially in response to stress or certain foods.

Serotonin also communicates with the brain-gut axis. When there is an imbalance or excess serotonin, it can exacerbate gastrointestinal symptoms, such as diarrhea, by affecting gut motility and sensitivity. This connection is particularly relevant in disorders like irritable bowel syndrome. In irritable bowel syndrome patients, excessive serotonin production can lead to increased intestinal motility and secretion, contributing to diarrhea.

Chronic stress can promote inflammation in the gastrointestinal tract, worsening conditions like irritable bowel syndrome. Chronic inflammation in the gut can lead to persistent diarrhea. The chronic nature of this inflammation affects the gut's ability to absorb nutrients properly and control water balance, leading to frequent and watery stools.

Altered Microbiome

Stress can negatively affect gut bacteria, which play a crucial role in digestion. Stress alters the balance of gut bacteria, reducing beneficial microbes (e.g., Lactobacillus and Bifidobacterium) and promoting the growth of harmful bacteria. This imbalance (dysbiosis) can impair digestion, increase intestinal permeability ("leaky gut"), and trigger diarrhea.

Stress can cause hyperactivity in the gut's enteric nervous system, speeding up intestinal contractions and leading to diarrhea. The microbiome’s altered composition may exacerbate these motility issues.

Beneficial gut bacteria produce short-chain fatty acids (SCFAs) which maintain intestinal health. Stress reduces SCFAs production, weakening the gut barrier and contributing to diarrhea.

Microvascular Changes

Prolonged stress may also lead to changes in microvascular blood flow in the intestines, affecting nutrient absorption and increasing susceptibility to diarrhea. In response to stress, your body increases blood flow to your muscles instead. This makes it harder to digest and absorb food.

Warning Symptoms

Warning symptoms of diarrhea associated with stress can include more than just the frequent and watery stools typical of stress-induced diarrhea. You should contact your healthcare provider if you have blood in stool, severe abdominal pain or cramps, fever, rapid weight loss, or dehydration symptoms such as dry mouth, dark urine, dizziness, and fainting. If any of these warning symptoms occur, it's important to seek medical advice promptly to rule out serious underlying conditions and receive appropriate treatment.

Tips to reduce Stress Diarrhea

The best approach is one that focuses on diet and lifestyle. You should:

• Avoid foods that can make diarrhea worse. Common triggers are dairy, spicy foods, artificial sweeteners, alcohol, and fatty foods.

• Reduce stress. Mediation, yoga, and deep breathing exercises can be especially helpful. Ensuring enough restful sleep is crucial for managing stress. Establishing a regular sleep schedule and creating a relaxing bedtime routine can improve sleep quality. If your anxiety levels are very high, you might benefit from therapy, with or without treatment with medications.

• Keep your body hydrated. Drink plenty of fluids like water, clear juice, broth, electrolyte solutions, or tea. Staying hydrated is crucial for managing stress as it helps maintain bodily functions and mental well-being. Proper hydration supports cognitive function, mood stability, and physical health, all of which can be adversely affected by stress.

• Keep track of patterns. If you notice that you get diarrhea every time you have an exam, you might want to start relaxing days in advance. This can help your body deal with stress more effectively.