While some people believe that they perform better under stress, that’s rarely the case. In fact, research has shown that stress makes a person more likely to make mistakes. 
Besides making you forget where you put your keys, stress can also have a dramatic impact on your health.

1. Stress Makes It Difficult to Control Your Emotions

It’s no secret that stressed people can fly off the handle. But new research tells us that how little stress is actually required for you to lose your cool.
A recent study by neuroscientists at New York University found that even mild levels of stress can impair our ability to keep a grip on our emotions. In their study, researchers taught subjects stress-control techniques. But after participants were put under mild stress by having their hands dunked in icy water, they couldn’t easily calm themselves down when shown pictures of snakes or spiders.
“Our results suggest that even mild stress, such as that encountered in daily life, may impair the ability to use cognitive techniques known to control fear and anxiety,” lead author Candace Raio said in a press release.

2. Stress Can Bring Out Disease

Some people are more prone to certain diseases, and chronic stress can give these conditions the green light. Stress has been linked to cancer, lung disease, fatal accidents, suicide, and cirrhosis of the liver (a side effect of combating with stress with alcohol). 
Researchers at Johns Hopkins University have discovered that children exposed to chronic stress are more likely to develop a mental illness if one runs in their families.

3. Stress Can Affect Your Love Life

While sex may be a good stress reliever, it can get you out of the mood quicker than you think.
A 1984 study found that stress can affect a man’s body weight, testosterone levels, and sexual desire. Numerous studies have shown that stress—especially performance anxiety—can lead to impotence. High levels of stress in pregnant women may also trigger changes in their children, specifically behavioral and developmental issues.

4. Stress Can Ruin Your Teeth

Some people respond to stressful situations through body language, including grinding their teeth. While often done unconsciously or during sleep, it can do lasting damage to your jaw and wear your teeth thin.
Some research has linked stress to gum disease, but this is mainly because of the habits of stressed-out people: less attention paid to oral hygiene, changes in saliva due to high levels of stress hormones, and decreased immunity.

5. Stress Can Ruin Your Heart

Stress can physically damage your heart muscle. Stress damages your heart because stress hormones increase your heart rate and constrict your blood vessels. This forces your heart to work harder and increases your blood pressure.
According to the American Institute of Stress, the incidence rate of heart attacks and sudden death increases after major stress-inducing incidents, like hurricanes, earthquakes, and tsunamis.

6. Stress Can Make You Fat

In the days of hunter-gathering, harsh conditions forces us to eat as much as possible when food was available, to store up for the hardship. That trait lives on inside us, and comes out when we are stressed.
Researchers at the University of Miami found that when people are placed in stressful situations, they’re likely to consume 40 percent more food than normal. They recommended turning off the nightly newscast before eating dinner to keep bad news at bay.  

7. Stress Can Make You Look Older

Chronic stress is a major contributor to premature aging.
Researchers from the University of California, San Francisco discovered that stress shortens telomeres—structures on the end of chromosomes—so that new cells can’t grow as quickly. This leads to the inevitable signs of aging: wrinkles, weak muscles, poor eyesight, and more.

8. Stress Weakens Your Immune System

The connection between mind and body are often underestimated, but everyone’s experienced a cold when they can least afford to. That’s because stress is so demanding on the body that the immune system suffers, making you more vulnerable to colds and infection.
The American Psychological Association recommends calming exercises, as well as social outlets, to relieve stress. 
Culled from Healthline