Did you know that spending 20 minutes in a hot sauna three times a week can be a highly effective treatment for depression? Randomized clinical trials have demonstrated this effect.
In 2019 I and my colleagues presented a scientific research review titled “The Role of Systemic Inflammation in Major Depressive Disorder and Implications for Novel Treatment Approaches” at the International Society for Affective Disorders annual conference. To summarize: we now have strong empirical evidence there is an immune-mediated component to depression, one of the most common and debilitating psychiatric disorders we face. Chronic, systematic inflammation is a significant cause of depression.
Chronic inflammation also represents a common mechanism of disease that contributes to virtually every chronic illness of modern life, including cancer, heart disease, pulmonary disease, autoimmune disorders, inflammatory bowel disease, obesity, and diabetes.
But let’s back up. What even is chronic, systemic inflammation?
Think about a time when you cut your finger – maybe a paper cut or a minor kitchen mishap. After the bleeding stopped, you probably noticed the wound turned red and swelled up a little. This is an example of acute inflammation, our body’s immune response to help prevent infection and heal the injury. Over the course of several days, as your finger mends, the visible inflammation recedes. Such inflammation is part of our immune system’s complex physiological response to protect the body from pathogens and to support cellular health and tissue repair.
Inflammatory processes can also be chronic and systemic – inflammatory proteins circulating through our bloodstream, affecting every cell in our body. When this occurs on a prolonged basis, we call it chronic, systemic inflammation. We can measure the severity of this type of inflammation in a number of ways, most commonly via blood tests that quantify levels of various biomarkers, such as C-reactive protein [CRP], IFN-alpha, IL-6, and IL-10. All of these are correlated with chronic diseases – all of the chronic diseases.
Making matters worse, chronic diseases in turn contribute to inflammatory reactions, and therefore the relationship between disease and inflammation is most likely bi-directional. In other words: a vicious cycle!
Our current understanding of mechanisms of action suggests that proinflammatory cytokines cross the blood-brain barrier and influence pathophysiologic domains. This includes decreased neurotrophic support, reduced brain monoamine levels, increased glutamate release/reuptake, oxidative stress, impaired brain plasticity, and activated neuroendocrine responses.
But why does this happen? And why is it so common?
The best explanation is that modern lifestyles in the industrialized world contribute to inflammation via behavioral habits (e.g., modern diets, sedentary lives, poor sleep routines) and environmental exposures that are incompatible with our evolutionary history as a species.
Among other things, this includes a plausible theory that modernity has led to a loss of natural exposure to previously available sources of anti-inflammatory, immunoregulatory signaling (i.e., “germs” or “old friends”) that were previously common in our soil, food, and gut microbiota. (If you want to nerd out, look up “tolerogenic microorganisms” and the “Pathogen Host Defense” theory).
Anti-Inflammatory Habits to Optimize Performance, Wellness, and Longevity
The good news is you almost certainly don’t need any medications to help manage chronic systemic inflammation. Lifestyle modifications and certain regular habits can reduce it. These include the following:
A sedentary lifestyle induces chronic systemic. Conversely, we also know that exercise has a powerful antidepressant effect, and there is good reason to believe a critical aspect of its mechanism of action is through an anti-inflammatory effect.
Sleep dysregulation – insomnia, jet lag, shift work, sleep deprivation – contributes to systemic inflammation. Strategies that improve sleep are beneficial to both inflammation levels. Make sure your sleep “hygiene” is dialed in. This means scheduling sufficient time in bed, going to bed at the same time every night, and sleeping in a dark, silent, and cool bedroom.
Timing the circadian clock:
Epidemiological data show that 80% of the general population is living a “shift work lifestyle” (e.g., chronic circadian rhythm disruption) and may be at risk for chronic diseases associated with inflammation. Strategies that optimize the circadian lifestyle, timing of therapies, and targeting specific circadian elements may be highly beneficial. Going to bed at the same time every night and getting 5-10 minutes of early morning direct sunlight on your eyes can work wonders.
Time-Restricted Feeding (TRF) or Intermittent Fasting:
Restricting eating to within a narrow window of time (12- or 8-hours, or even less) every day may offer a range of health benefits associated with reduced inflammation, including weight management and improved mood and cognition. In a study conducted with mice, it was found that TRF (10-hour feeding window) prevented obesity and metabolic syndrome even when mice were allowed to eat the same number of calories that caused other mice (non-TRF) to rapidly gain weight. A TRF approach in humans may have a similar benefit and enhance cellular defenses against metabolic stress. It is also probably more consistent with the feeding pattern of our ancestors.
Eating a whole foods diet (e.g., a Mediterranean or Ketogenic diet) that minimizes added sugar, processed foods, alcohol, and refined grains – and maximizes healthy fats, quality proteins, fiber, natural vegetables, and some fruits has been shown to have an anti-inflammatory effect. A recent meta-analysis found that adherence to the Mediterranean diet or a diet low on the Dietary Inflammatory Index was associated with a lower risk of depression and inflammation. Eating highly processed junk food increases the risk of becoming and remaining depressed. One randomized controlled trial found that flavonoid-rich chocolate (e.g., 2 grams of dark chocolate with 70% cocoa) significantly prevented DNA damage, improved the nucleus integrity of cells, and improved biochemical parameters (total cholesterol, triglycerides, LDL-cholesterol) and waist circumference. Moreover, another recent study found that an anti-inflammatory diet is associated with reduced all-cause mortality.
Drink plenty of water, about 80-120 ounces a day, more if sweating heavily.
Certain naturally occurring compounds may be valuable as both foods and dietary supplements for reducing inflammation, including turmeric/curcumin and Omega 3 fatty acids. A recent randomized controlled trial found that adjunctive supplementation with turmeric/curcumin (500-1500 mg/day) had significant antidepressant effects in patients with major depressive disorder, with a larger effect in males than in females.
As we learn more about the connection between gut microbiota and systemic inflammation, evidence suggests probiotic supplementation, as well as foods that support gut health (e.g., fermented foods, bone broth), may be anti-inflammatory. Fermented foods include yogurt, kefir, miso, and anything that is naturally pickled without the use of vinegar.
Psychological stress leads to increased production of pro-inflammatory cytokines, and therefore strategies to manage levels of perceived stress and responses to stress have an anti-inflammatory effect. Recovery practices have shown profound benefits. Such practices include meditation, yoga, Jiu Jitsu, religious/spiritual practices, unplugging from digital connections, spending time outdoors (e.g., “forest bathing”), soothing hobbies, and positive social support.
Sauna bathing, cold immersion, float therapy:
Hyperthermia (e.g., Finnish-style sauna bathing) is associated with reduced systemic inflammation and a range of health benefits, including reduced risk of vascular and cardiovascular diseases, neurocognitive diseases, pulmonary diseases, and all-cause mortality. Other recovery practices – cold immersion (ice baths), and float tank therapy – also appear to have powerful anti-inflammatory benefits.
Chronic, systemic inflammation plays a powerful role in the etiology of virtually all chronic diseases. It is primarily caused by many aspects of our modern lifestyle and dietary habits. Modifying your habits to live a more “ancient lifestyle” will reduce inflammation, enhance metabolic and immune functioning, and improve your overall health and functioning.
About the author:
B. Christopher Frueh, Ph.D. is a novelist, clinical psychologist, and professor of psychology at the University of Hawaii. He has over thirty years of professional experience working with veteran and military communities; has conducted clinical trials, epidemiological, and neuroscientific empirical studies; and has co-authored over 300 scientific publications. This essay is adapted from Operator Syndrome, forthcoming.