According to the Gallup 2019 Global Emotions Report, a third of the world’s population (that’s over 2.5 billion people) felt stressed, worried and/or angry in 2019. Since then, over 6 million people have died from COVID-19, inflation has spiraled out of control and a major war has broken out in Europe. So clearly stress is here to stay, and its prevalence and intensity is probably at an all-time high. But can stress cause illness or a medical disorder?

More and more, research is saying yes. While previously diseases were thought to result mainly from our inherited genetics, evidence now shows that epigenetic factors such as environment, diet and stress can negatively influence the expression of our DNA, leading to many chronic health conditions and illnesses. Fortunately, removing stressors from our life and relaxing can go a long way in reversing these epigenetic changes and restoring health.

The genetic model of disease

For many years, we were led to believe that the key to our health and wellness lies in our DNA. Certain diseases were thought to be associated with genetic mutations or defects that caused us to become ill. If you “had the gene” for a certain trait or illness, it was generally presumed that there was little you could do about it. One day, a particular disease that you were genetically predisposed to would “kick in” and you would become sick — a rather depressing and fatalistic view of our health.

The latest science is actually a lot more hopeful. Although our DNA is still a critical element in our overall functioning as human beings, and while we cannot change the actual DNA sequence we are born with (except through artificial interventions on small genomic regions using CRISPR or TALEN), it turns out that it is really the expression or non-expression of certain genes in our DNA that play the most critical role in our health and well-being. This brings us to the burgeoning field of epigenetics.

Epigenetics: cause for hope

Translated literally, the word “epigenetics” means “above genetics”. Epigenetics refers to the idea that factors beyond the genetic code itself — such as nutrition, environment, stress and other external variables — affect the expression of DNA without altering the basic code itself. Epigenetic factors can influence certain genes to turn on or off, which in turn impacts protein production, which eventually affects our entire body chemistry and therefore our state of health (or lack thereof).

One critical factor in epigenetic expression is stress. While stress is often hard to define clinically, as so much of stress is subjective, feelings of stress do almost always correlate with corresponding measurable physical symptoms such as anxiety and chemical changes that reflect the state of stress.

In a study from Johns Hopkins University, researchers found that injecting mice with corticosterone, the hormone that mice produce when stressed out, altered the expression of numerous genes associated with the hypothalamic-pituitary-adrenal (HPA) axis, a network associated with stress response. One of the genes, Fkbp5, has been associated with Post Traumatic Stress Disorder (PTSD) and mood disorders. 

Can stress cause illness?

When stress gets out of control, the epigenetic changes that it induces can cause us to cross over from mere discomfort into actual illness. Stress has been associated with innumerable illnesses such as:

1. Insomnia — which increases your risk of developing many major disorders: In one study, researchers concluded that increased stress is a significant predictor of poor sleep quality. Poor sleep quality can contribute to the development of more serious conditions, such as obesity. A 2018 study found that “individuals who regularly slept less than 7 hours per night were more likely to have higher average body mass indexes and develop obesity than those who slept more.” Obesity can, in turn, snowball into metabolic syndrome, which increases the risk of serious health conditions such as heart disease, stroke and type 2 diabetes.
   
   
2. High blood pressure: Stress can contribute to elevated blood pressure, which can put you at risk for many cardiovascular diseases, such as coronary heart disease, heart attack, stroke, heart failure, and more. See: 7 Ways To Reduce Stress And Keep Blood Pressure Down.
   
   
3. Migraines: One study showed that “50-80% of patients report stress as a precipitating factor for migraine headaches,” while another study found that stress intensity correlated with headache frequency. Additionally, migraine incidence is higher when an individual’s stress scores are higher in the previous year. Furthermore, retrospective studies show that stressful childhood events such as sexual and physical abuse are found to be more frequent in those with migraines than in those that don’t have migraines.
   
   
4. Immune deficiency: Can stress reduce immunity? Over the past 30 years, more than 300 studies have been done on stress and immunity in humans, and together they have shown that psychological challenges are capable of modifying various features of the immune response. A 2004 meta-analysis found that chronic stressors were associated with suppression of both cellular and humoral immunity. However, they admit that there is little or no evidence linking stress-related immune change in healthy humans to disease vulnerability; rather, they opine that the immune system is remarkably flexible and capable of substantial change without compromising an otherwise healthy host. On the other hand, the flexibility of the immune system can be compromised by age and disease, implying that stress can trigger, rather than cause, reduced or compromised immunity, which can then lead to disease worsening.
   
   
5. Microbiome destabilization and gastrointestinal (GI) disorders: The gut microbiome, or the ecosystem of bacteria found in the human digestive system (gut), is increasingly seen as critical in the modulation of overall health. One study found that the destabilization of microbial diversity seen after trauma is potentially caused by stress. Researchers also say that exposure to stress leads to the development of many GI disorders such as inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and gastroesophageal reflux disease (GERD). 
   
   However, whether stress is “causative” directly or just a triggering behavior (that can lead to more causative variables, such as high alcohol use or taking too many pain meds) leading to gut distress remains under study. Clearly, the early notion that ulcers, as an example, are caused by stress has been refuted by the medical establishment, based on research showing that it’s actually Helicobacter pylori (commonly called H. pylori) in the gut that causes ulcers. On the other hand, in most ulcer cases where H. pylori is present, stress is often involved, as well. — so the impact of the two factors may be additive. Regarding other gastrointestinal (GI) disorders, much research now connects stress with the developmental trajectory of the intestinal barrier and an increase in gut permeability, although the reverse (gut health impacts stress) may be even more prevalent. In fact, pharmaceutical companies are actively investigating gut health treatments as a way to treat myriad psychiatric conditions (see #6, below). Receiving the most attention: Irritable bowel syndrome (IBS), now classified as a “stress-related functional brain-gut-microbiota axis disorder.” 
   

6. Mental illnesses: Stress is also considered a major factor in the development of many mental disorders, including:
   
   
7. Anxiety disorders: Researchers found a direct and significant correlation between perceived stress and symptoms of anxiety.
   
   
8. Bipolar affective disorder: Individuals with bipolar disorder were found to report more stressful life events than healthy individuals.
   
   
9. Depression: Perceived stress has been found to be associated with depressive symptoms.
   
   
10. Dissociative disorders: Dissociative experiences are more common when people are stressed, and those symptoms decrease when stress is reduced.
    
    
11. Eating disorders: Psychological distress and perceived stress have been found to have a strong association with eating disorder symptoms.
    
    
12. Obsessive Compulsive Disorder: A study found that in patients with OCD, cortisol levels and perceived stress scores were significantly higher than in control subjects.
    
    
13. Psychosis: Perceived stress was found to be correlated with higher scores on the community assessment of psychic experiences (CAPE), as well as with psychotic-like experiences (PLE).
    
    
14. Schizophrenia: Patients with schizophrenia have significantly higher allostatic load (AL) of stress than healthy control subjects in both early and chronic schizophrenia. 

7. Many other illnesses: While the research is in the early stages, stress is thought to be a precipitating factor in many other illnesses, including asthma, Alzheimer’s, certain cancers and autoimmune syndromes. 
   

In summary, stress can trigger numerous acute physical and mental conditions and even put you at risk for certain chronic illnesses. Fortunately, there is plenty you can do to manage your stress levels, reverse the epigenetic changes caused by stress and restore balance and well-being. Here are some proven strategies for keeping stress at bay.

Tips to reduce stress

• Exercise and lose weight: A study from Duke University found that exercise and stress management training were able to reduce emotional distress and improve markers of cardiovascular risk in patients with ischemic heart disease.
  
  
• Practice Pranayama techniques to relax: Pranayama, an ancient science that originated in India, centers on the concept that the flow of vital force (or prana) throughout the body is critical in maintaining health. Various breathing techniques, called Pranayama, are highly effective in reducing stress. In one study, researchers found that stress levels in participants reduced after two months of pranayama. Another study found that practicing slow pranayama techniques reduced perceived stress and also had beneficial effects on cardiovascular parameters such as heart rate, diastolic blood pressure and mean arterial pressure.
  
  
• Sleep better: In a complex relationship, good sleep is critical for managing stress levels, and stress can be a causative factor in poor sleep. The Sleep Foundation offers great tips on how you can sleep better, including choosing quality bedding, avoiding light disruption, cultivating a quiet and peaceful atmosphere and using pleasant aromas to relax your mind and prepare for sleep. See also: Why Sleep Matters For Your Metabolic Health.
  
  
• Meditate: Meditation is increasingly being proven as one of the most effective and safe ways to deal with a variety of chronic health conditions, including stress. In an 8-week study of Alzheimer’s patients and their caregivers, a twice-daily meditation program reduced perceived stress and improved sleep, mood, memory and blood pressure. One very effective meditation practice is Heartfulness Meditation, a program found to significantly reduce perceived stress and improve sleep quality. (To start Heartfulness Meditation, you can download the HeartsApp app and connect virtually with a trainer for free.) 
  

• Yoga: Arguably a practice that combines exercise with meditative aspects, yoga has been shown to significantly reduce depression, anxiety, and stress in as little as 12 sessions.                       
  
  
• Write in a journal: A study concluded that Positive Affect Journaling (PAJ) decreases mental distress, depressive symptoms and anxiety (which correlates very closely with stress), and also increases overall feelings of well-being.
  
  
• Eat better: A poor diet can contribute to feelings of stress. A joint review found that, overall, excessive sodium intake is associated with several negative health outcomes. Other food recommendations include avoiding excess caffeine and alcohol while increasing intake of stress-reducing foods such as whole grains (e.g., quinoa) and other high-fiber foods, nuts, foods rich in Vitamin D (e.g., mushrooms), foods rich in B6 vitamins and folic acid (e.g., dark, leafy greens like spinach), foods high in Omega-3 fatty acids (e.g., salmon), foods rich in magnesium (all the aforementioned foods) and fermented foods (e.g. kefir, sauerkraut, yogurt).
  
  
• Build strong relationships with friends and family: Many studies show the positive effects of strong relationships on numerous stress-related measures. In fact, supportive, close relationships, such as high-quality marriages and parental warmth, have been associated with “lower scores on multi-system indices of biological risk, which include aggregate assessments of the HPA axis, SNS (Sympathetic Nervous System), cardiovascular, metabolic, and immune systems.”
  

Key takeaways

Can stress cause illness? The answer, clearly, is yes. If not attended to, stress can trigger or be a contributing factor of serious illnesses such as metabolic syndrome, cardiovascular diseases, migraine headaches, immunodeficiency disorders, gastrointestinal problems, mental illnesses and many others. Fortunately, you can take steps to significantly reduce stress and reverse negative epigenetic changes by incorporating practices such as sleep hygiene changes, yoga, more consistent exercise, pranayama, meditation, journaling, dietary improvements and increased attention to building and maintaining strong social relationships.