Certain people are able to heal from wounds rapidly and endure painful experiences, like surgery without anesthesia, without so much as a flinch. They must be superheroes, right? Wrong. Any human can do it, including you. Our perceptions of certain situations can affect our health both positively or negatively.

A well-known and well-documented case of specific mindset affecting health is the placebo effect. It refers to health benefits from medicines that should have no effect, such as inert pills and false surgeries. In the 1960s, breakthrough studies showed the potential physiological effects of dummy pills—patients would react accordingly to what they were told they were given. For example, if a patient was told he was given a stimulant, his pulse and blood pressure would increase and his reaction rates would improve, even though he was given a placebo. Similarly, “if you think you’re going to get better, you will get better,” psychology teacher Alice McCraley said.

Regretfully, a subcategory under the placebo effect is the nocebo effect. As the placebo effect has a positive effect on health, the nocebo, or “I will harm” in Latin, negatively affects one’s health. If patients believe in the worst, chances are, that is what they are going to get. “[Patients are] convinced that something is going to go wrong, and it’s a self-fulfilling prophecy,” Arthur Barsky, a psychiatrist at Boston’s Brigham and Women’s Hospital, told The Washington Post.

But how does this happen? “Pain sensors in your body send the signals to the brain,” psychology teacher John Hebert said. “However, it is the brain that perceives the pain and your mindset can determine how you feel the pain.” According to Hebert, humans have some conscious control of pain.

An example of the power of one’s mindset can be shown with an experiment involving hypnosis, according to Hebert. A young woman was hypnotized, or put into a state of deep relaxation and concentration. Before her arm was submerged in ice water, researchers suggested she would feel no pain. The other subject wasn’t hypnotized or warned before his arm was submerged. Periodically, each subject reported the pain on a 10-point scale, 10 being the most painful. The one not hypnotized escalated to a ten rapidly, while the hypnotized one stayed at a one for the entire experiment. “Pain sensors are always reporting, but the brain is making its own interpretations,” Hebert said.

According to Hebert, the trick to staying relaxed is to utilize your parasympathetic, or the “rest and repose,” nervous system. Calming down, relaxing muscles and practicing deep breathing patterns can divert the brain’s attention to pain. Hebert used a relaxation technique similar to hypnosis during his nose surgery without anesthesia.

During stressful situations, the body is more vulnerable to illness. “Stress leads to a physiological response,” McCraley said. “Your body basically has to fight something off.” Stress is linked with the sympathetic, or “fight or flight,” nervous system. “Being stressed is basically like fighting a battle,” Hebert said. “If you are unable to restore yourself to calm your immune system will eventually weaken.” Researchers have found a correlation between stress and cortisol levels in the body; the more stressed a person is, the higher the cortisol levels. Cortisol, a hormone, increases blood pressure and blood sugar and reduces immune responses. If a person is continually stressed and continues to have high cortisol levels in his or her body, exhaustion is the outcome. This leaves the person vulnerable to the common cold.

Sleeping, not eating stimulants, like caffeine and not dwelling on stressful situations are all essential to staying healthy. “And of course, actually studying for finals would probably alleviate some stress,” Hebert said.