The mind could indeed be strong enough to interact with the body and change its physical strength. Descartes and his dualism would have been triggered by such findings!
L. D. Kubzanski et al. investigated whether there was an actual relationship between optimism, pessimism and coronary heart disease cases in old men. In 1986 they asked over a thousand men to complete an optimism-pessimism scale. They did a follow up during approximately 10 years and in that time, 162 cases of heart diseases occurred. After 10 years it was finally time to analyse these precious data!
Those 162 cases of heart diseases were categorized and analysed with the scores of optimism and pessimism and it was found that men who were more optimistic had less chances of getting a heart disease. It was also proven that negative emotions like anxiety, depression and anger are increasing the risk of coronary heart diseases.
Start adopting a more positive mind-set. You will thank me later!
Reference: Kubzansky, L. D., Sparrow, D., Vokonas, P., & Kawachi, I. (2001). Is the Glass Half Empty or Half Full? A Prospective Study of Optimism and Coronary Heart Disease in the Normative Aging Study. American Psychosomatic Society. 910-6