Have you ever experienced a dark night of the soul, a time of spiritual isolation when you felt utterly disconnected from God? 

I know firsthand that this feeling — which can last not just a night, but days, or even years — can be debilitating.

Not all spiritual crises are that extreme. Sometimes we just don’t feel like praying. Other times we feel stressed and retreat into ourselves. When these moments arise, what can we do?

One answer can be found in biology.

In recent years, many researchers have turned to the study of inflammation, our bodies’ attempt to protect themselves from invading pathogens, bacteria and viruses. 

Though it has a negative connotation, inflammation is a good thing. Scratch yourself on a piece of broken glass and your white blood cells will release chemicals to keep harmful substances from enÙtering your bloodstream. Without inflammation, our bodies would not heal.

Severe complications arise, however, when inflammaÙtion becomes chronic. Our bodies turn on themselves, atÙtacking normal tissue as foreign bodies. This can cause cancer, arthritis, heart attacks and autoimmune diseases. 

We don’t completely know why this happens, but genetics, our reactions to stress, lack of sleep and poor diet seem to play a role.

Spiritual maladies

What’s the connection with our spiritual lives? 

Just as our bodies protect themselves from injury with inflammation, our souls react to stress with patterned responses. We become anxious when a loved one is sick. We feel irritated after an argument. Insomnia rears its ugly head after problems at work. 

Our feelings and emotions are natural responses to the spiritual breaks, cuts, bruises and threats we experience. They alert us when something is wrong. 

Problems arise when those emotional and spiritual reactions turn chronic. Fear, worry and stress start running the show. Repressed emotions can lead to not just a dark night, but arthriÙtis of the soul — our minds become rigid and our hearts harden. We fall into laziness and depression, preventing us from loving God and those around us.

I am not a medical professional or psychologist. However, I have spent the past two decades studying spiritual practices. I have seen and experiÙenced relief, healing and transformation through simple acts of prayer. These devotions have provided solace and direction during times of trouble, and can be anti-inflammatories for the soul. 

A staple in my life is the Jesus Prayer.  

The Jesus Prayer is a simple meditation popularized by the 19th-century spiritual text “The Way of a Pilgrim.” Written by an anonymous Russian, it chronicles a peasant’s search for God through this prayer.

During my own bout of chronic spiritual inflammation, I discovered the prayer, not in that book, but in “Franny and Zooey,” by J. D. Salinger, beloved author of “The Catcher in the Rye.” 

In the book, Franny, who is having a difficult time with her boyfriend, picks up “The Way of the Pilgrim” and begins saying the Jesus Prayer: “Lord Jesus Christ, have mercy on me.” She repeats this until she enters a deep, prayerful, meditative state.

I remember thinking, “That’s pretty easy. I can do that!” I stopped reading and prayed those simple words over and over again. 

At first I felt nothing, but something inside pushed me to make a commitment. I recited it when I woke up and when I went to sleep. Over time I caught myself saying it walking down the street, waiting in traffic or when dealing with a problem at work. 

Spiritual healing

Though I can’t prove this scientifically, I feel like the prayer changed the way my heart beat. I felt calmer. I worried less. I felt closer to God. What had happened to me?  

The author of “The Way of the Pilgrim” describes it:

“The Jesus Prayer is a continuous, uninterrupted call on the holy name of Jesus Christ with the lips, mind, and heart; and in the awareness of His abiding presence it is a plea for his undertakings, in all places, at all times, even in sleep. … 

“Anyone who becomes accustomed to this prayer will experience great comfort as well as the need to say it continuously. He will become accustomed to it in such a degree that he will not be able to do without it and eventually the Prayer will of itself flow in him.”

Like the rosary, the Jesus Prayer is a devotion of repetition. You don’t say it just once, but 100 times, 1,000 times. 

It’s a constant reminder of our need for mercy and love. You can say the prayer while rocking a child to sleep or standing in line at the store. You can make it a part of everything you do.

While you should always seek professional advice for what ails you, the Jesus Prayer — approached with a sincere heart and an eagerness to get closer to God — can be an effective medicine to heal our inflamed spirits.

It can also be a faithful companion as we wait for the night to break and the sun to rise.

Gary Jansen is the director of Image Books at Penguin Random House and the author of “The 15-Minute Prayer Solution.” His most recent book is “Life Everlasting: Catholic Devotions and Mysteries for the Everyday Seeker” (TarcherPerigree, $17).