There is a Torah commandment to guard our health. High levels of stress cause many health problems. Your immune system works best when you are calm and serene. The efforts one makes to alleviate stress is the fulfillment of the Creator’s will. As our loving Father, He wants us to be well.
Viewing decreasing stress and increasing serenity as a spiritual obligation will raise this to a higher priority. Moreover, we should strive to experience joy in doing the Almighty’s will (in Hebrew this is called Simcha shel mitzvah). This adds a major dimension to the entire process.
-from Rabbi Zelig Pliskin’s book, “Serenity,” p.108