Who Has Side Effects from Coffee?

Coffee containing caffeine may cause insomnia, nervousness and restlessness, upset stomach, nausea and vomiting, increased heart and respiratory rate; learn about 9 side effects of too much coffee.

Who Has Side Effects from Coffee?

Coffee containing caffeine may cause a range of side effects, from insomnia and nervousness to increased heart rate and respiratory rate.


is possibly unsafe when taken in high doses, and research has shown that your genes have a big influence on your tolerance to it. Some may consume much more caffeine than others without experiencing negative effects, while those who are not used to caffeine may experience symptoms after consuming what is normally considered a moderate dose. Here are 9 side effects of too much caffeine, and how it affects sleep.

Caffeine-induced anxiety disorder is one of four caffeine-related syndromes listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Extremely high daily intakes of 1000 mg or more per day have been reported to cause jitters, nervousness and similar symptoms in most people, while even a moderate intake can cause similar effects in people sensitive to caffeine. In addition, modest doses have been shown to cause rapid breathing and increase stress levels when consumed all at once. Studies have found that increased caffeine intake seems to increase the amount of time it takes to fall asleep, and can also decrease total sleep time, especially in the elderly.

On the contrary, low or moderate amounts of caffeine do not seem to affect sleep much in people considered “good at sleep”, or even in those with self-reported insomnia. The laxative effect of coffee has been attributed to the release of gastrin, a hormone produced by the stomach and accelerating activity in the colon. In addition, decaffeinated coffee has been shown to produce a similar response. Caffeine itself also seems to stimulate bowel movements by increasing peristalsis, the contractions that move food through the digestive tract.

Although coffee was believed to cause stomach ulcers for many years, a large study of more than 8,000 people found no relationship between the two. On the other hand, some studies suggest that caffeinated beverages may worsen gastroesophageal reflux disease (GERD) in some people. In addition, there have been several reports of rhabdomyolysis related to excessive consumption of caffeine, although this is relatively rare. Research has shown that although caffeine stays in the body for an average of five hours, the length of time can range from one and a half to nine hours, depending on the individual.

Researchers gave 400 mg of caffeine to 12 healthy adults six hours before bedtime, three hours before bedtime, or immediately before bedtime. Both the time it took for the three groups to fall asleep and the time they spent awake at night increased significantly. Although caffeine does not seem to cause classic addiction as drugs do, if you drink a lot of coffee or other caffeinated drinks on a regular basis, it is very likely that you will become dependent on its effects. It has been shown to increase blood pressure due to its stimulating effect on the nervous system.

It can also cause a heart rhythm disturbance called atrial fibrillation which has been reported in young people who consumed energy drinks containing extremely high doses of caffeine. A detailed review suggests that although caffeine triggers certain brain chemicals in a similar way as cocaine and amphetamines do, it does not cause classic addiction as these drugs do. In one study, 16 people who normally consumed high, moderate, or no caffeine participated in a word test after not consuming caffeine during the night. Only high-caffeine users showed a bias for caffeine-related words and had strong cravings for caffeine.

In conclusion, although coffee containing caffeine may cause insomnia, nervousness and restlessness, upset stomach, nausea and vomiting, increased heart and respiratory rate, and other side effects; it is important to pay attention to dosage and timing of caffeine consumption as it can increase blood pressure and cause heart rhythm disturbances. It is best to limit your intake to about 250 mg of caffeine per day unless you are used to consuming more.

Glenna Matthys
Glenna Matthys

Hardcore internet practitioner. Wannabe beer advocate. Infuriatingly humble beer expert. Devoted coffee evangelist. Hardcore social media scholar. Friendly beer fanatic.