Gratitude for the positives in life might improve mood and sleep, according to a rare study examining the effect of spirituality on heart failure patients.

Researchers associated with the Chopra Center for Wellbeing in California studied 186 men and women diagnosed with asymptomatic heart failure for at least three months. The team compared their psychological test scores for gratitude and spiritual well-being with scores for depressive symptoms, sleep, self-efficacy and inflammatory markers.

Results published in the journal Spirituality in Clinical Practice found higher gratitude scores were associated with better mood, more quality sleep and more self-efficacy.

For eight weeks researchers also asked some of the patients to write down three things for which they were thankful most days of the week. Those patients showed reductions in circulating inflammatory biomarkers and an increase in heart rate variability, according to lead author Paul J. Mills, Ph.D., of the University of California, San Diego.

“It seems that a more grateful heart is indeed a more healthy heart,” Mills observed.

The researchers said gratitude among Stage B heart patients is particularly important, as it is a critical time for therapeutic interventions that can slow progression.