A recent book discusses the combined effect of belief and stress on the body:

It has been commonly known from decades of psychological research that life’s adversities and stresses can cause harm to the human body. This assumption has been upended in recent years. It is now known that a Christian’s proper attitude toward trials and adversities being under God’s control results in better health both in mind and body.

It may make intuitive sense that stress is harmful for health. But research now shows that it may not be stress that poses a risk to one’s health but the belief that stress is bad for you. ... For example, one study estimated that over an eight-year period, 182,000 Americans suffered early deaths not because of the stress that they were under, but because of their belief that the stress was harmful to their health.

There are no or very minimal negative effects when a major or minor stressful circumstance is viewed as a challenge. A study was conducted of executives who were experiencing high levels of work-related stress. It found that those who interpreted the stress as a challenge rather than as a threat experienced few negative consequences. They were resilient. In metallurgy, resilience refers to a material’s ability to bend but not break under physical stress. Resilient people are people who “bend but do not break” when under psychological stress.

Source: James E. Alcock, “Belief: What It Means To Believe And Why Our Convictions Are So Compelling,” (Prometheus Books, 2018)