Most of the time, people think of their mind and their body as totally separate entities. People commonly speak as if their body is somehow disconnected from their self. “My body does not appreciate the hard workout I did.” “My body is telling me I need more sleep.” “My legs are protesting.” Such statements are common, and few people pay attention to or notice the way such comments distance people from their own bodies. 

The unconscious belief that a person is somehow separate from their body can cause serious damage. This sense of separation can mean that a person does not feel the need to protect their body as they should. Many an athlete has lived the mantra of “mind over matter” only to find that their determination to “push through” and “dig deep” has lead them to ignore their body’s warnings and resulted in serious and lifelong injury. 

Determination and a nearly masochistic perseverance is not the only way that a person’s mind can put their body in danger. The mind and the body are linked, and a person’s thoughts and emotions can express themselves as physical symptoms.

Negative emotions, thoughts and experiences can have a serious effect on a person’s body. Many people have at least heard that stress, a mental sensation, has physical effects. Most people have also experienced these effects in the form of stress headaches, sore muscles from unconsciously holding their shoulders rigidly and various forms of insomnia. Stress is also known to effect immunity in contradictory ways. Minor and short term stress is known to boost the immune system temporarily only for the system to “crash” once the stress has passed. This is why so many college students are perfectly healthy throughout their exam period but fall ill almost immediately after their tests are finished. 

Long-term or chronic stress causes nothing but damage to the human body. “Stress leaves you in a flight or fight state in which your body turns off long-term building and repair projects,” said Robert Sapolsky, a professor of biological sciences at Stanford. “Memory and accuracy are impaired. Patrols for [invading germs] aren’t sent out, you tire more easily, you can become depressed and reproduction gets downgraded.” Chronic stress also results, in many cases, in chronic insomnia which brings with it a whole host of extra issues including brain inflammation, impaired judgment and reflexes, increased risk of heart disease and hallucinations.

Anger and resentment also have a serious effect on a person’s body. According to scientists at Ohio State University, arguments between significant others can slow a person’s healing ability by more than a day. If the couple argues regularly, the time it takes for physical wounds to heal is more than doubled. Researchers compared how long it took tiny blisters to heal in couples that argued and those that did not. The blisters on the couples who argued took roughly 40 percent longer to heal. Researchers posit that this is because the arguments caused a surge in cytokines, the molecules that trigger inflammation. These molecules have been linked to arthritis, diabetes, heart disease and cancer.

Bottling up anger has proven to be nearly as bad as having it out with a partner. A Michigan study found that women who suppressed their anger in confrontation with their partners had twice the risk of dying from heart disease, stroke or cancer.

“A good cry” is often said to be very cathartic, and there is a scientific reason for that. U.S. biochemist Dr. William Frey compared the tears of women who cried for emotional reason with those whose tears were caused by exposure to onions. Frey found that emotional tears were found to contain high levels of stress hormones. He concluded that the purpose of emotional crying is to remove stress chemicals from the body and holding back those tears leaves the body prone to anxiety, weakened immunity, impaired memory and poor digestion.

While negative emotions have a negative effect on the body, the opposite is true of positive emotions. Happy and positive thoughts have been shown to improve people’s health in small but noticeable ways. For example, cardiologists at the University of Maryland Medical Center found that laughing can reduce the risk of a heart attack by curbing unwanted stress. A study by Dr. Lee Berk of Loma Linda University in California produced similar results. Berk found that laughter boosted both “feel good” beta endorphins by 27 percent and the human growth hormone, which aids sleep and cellular repair, by a whopping 87 percent. The stress hormones cortisol and adrenalin, in contrast, can be lowered by the mere anticipation of laughter. 

Love and affection had similarly beneficial effects. Expressing affectionate feelings towards a loved one was found to lower cholesterol levels while the actual act of falling in love raises a person’s nerve growth factor for nearly a year. This hormone-like substance helps restore the nervous system, improve memory and trigger the growth of new brain cells. 

Gratitude, meanwhile, has some of the most powerful physical effects of any positive emotions a person can feel. Thankful feelings have been found to boost immunity, lower a person’s blood pressure and speed a person’s healing of wounds. Dr. Rollin McCraty of the Institute of HeartMath in the U.S. also found that gratitude could trigger oxytocin. “[Oxytocin] switches off stress by causing the nervous system to relax,” said McCraty. “Oxygenation to tissues increases significantly, as does healing. We’ve found that gratitude is also associated with the more harmonious electric activity around both the heart and brain – the very state in which these organs operate most effectively.”

The very real effects both positive and negative emotions have on the human body makes it clear that the mind and the body are not as separate as many people believe. They are interconnected and, just as physical trauma can cause mental damage, so can emotional struggles cause physical difficulties. It appears that, when it comes down to it, the Buddha was correct when he said, “What you think, you become.”