What kind of stimulant is caffeine

Effects of caffeine There is no safe level of drug use. Caffeine affects everyone differently, based on: size, weight and health whether the person is used to taking it whether other drugs are taken around the same time the amount taken The following effects may be experienced within 30 minutes after consuming caffeine, and may continue for up to 6 hours: feeling more alert and active restlessness, excitability and dizziness anxiety and irritability dehydration and needing to urinate more often higher body temperature faster breathing and heart rate headache and lack of concentration stomach pains.

Long-term effects Regular, heavy use of caffeine such as more than 4 cups of coffee a day may eventually cause: anxiety difficulty sleeping ulcers osteoporosis in post-menopausal women irritability and headaches dizziness and ringing in the ears muscle tremor weakness and fatigue rapid heart rate and quickened breathing rate poor appetite, nausea, vomiting and diarrhoea increased thirst, frequent urination or increased urine volume irregular heart rate or rhythm low blood pressure with faintness or falls seizures, confusion or delirium.

Read more about withdrawal. In Australia between and , there were calls to the NSW Poisons Information Line concerning toxicity from caffeinated energy drinks. Ontario: Addiction Research Foundation; Kaye S. Caffeine: What you need to know. National Drug and Alcohol Research Centre; Upfal J. The Australian drug guide. Melbourne Black Inc. Health effects of energy drinks on children, adolescents, and young adults.

Consumption of energy drinks by children and young people: a rapid review examining evidence of physical effects and consumer attitudes. This is the amount in two or three ounce cans of cola soda. Caffeine is associated with several health conditions. People have different tolerances and responses to caffeine, partly due to genetic differences.

Consuming caffeine regularly, such as drinking a cup of coffee every day, can promote caffeine tolerance in some people so that the side effects from caffeine may decrease over time.

Although we tend to associate caffeine most often with coffee or tea, the research below focuses mainly on the health effects of caffeine itself. Visit our features on coffee , tea , and energy drinks for more health information related to those beverages. Caffeine can block the effects of the hormone adenosine, which is responsible for deep sleep. Caffeine binds to adenosine receptors in the brain, which not only lowers adenosine levels but also increases or decreases other hormones that affect sleep, including dopamine, serotonin, norepinephrine, and GABA.

Caffeine intake later in the day close to bedtime can interfere with good sleep quality. Although developing a caffeine tolerance by taking caffeine regularly over time may lower its disruptive effects, [1] those who have trouble sleeping may consider minimizing caffeine intake later in the day and before going to bed. In sensitive individuals, caffeine can increase anxiety at doses of mg or more a day about 4 cups of brewed coffee.

High amounts of caffeine may cause nervousness and speed up heart rate, symptoms that are also felt during an anxiety attack. Those who have an underlying anxiety or panic disorder are especially at risk of overstimulation when overloading on caffeine. Caffeine stimulates the heart, increases blood flow, and increases blood pressure temporarily, particularly in people who do not usually consume caffeine.

However, strong negative effects of caffeine on blood pressure have not been found in clinical trials, even in people with hypertension, and cohort studies have not found that coffee drinking is associated with a higher risk of hypertension. Studies also do not show an association of caffeine intake and atrial fibrillation abnormal heart beat , heart disease , or stroke.

It may help to boost energy if one is feeling fatigued from restricting caloric intake, and may reduce appetite temporarily. Caffeine stimulates the sympathetic nervous system, which plays a role in suppressing hunger, enhancing satiety, and increasing the breakdown of fat cells to be used for energy.

Caffeine can cross the placenta, and both mother and fetus metabolize caffeine slowly. A high intake of caffeine by the mother can lead to prolonged high caffeine blood levels in the fetus. Reduced blood flow and oxygen levels may result, increasing the risk of miscarriage and low birth weight.

A review of controlled clinical studies found that caffeine intake, whether low, medium, or high doses, did not appear to increase the risk of infertility. Most studies on liver disease and caffeine have specifically examined coffee intake. Caffeinated coffee intake is associated with a lower risk of liver cancer, fibrosis, and cirrhosis. Caffeine may prevent the fibrosis scarring of liver tissue by blocking adenosine, which is responsible for the production of collagen that is used to build scar tissue.

Studies have shown that higher coffee consumption is associated with a lower risk of gallstones. Therefore, it is likely that caffeine contributes significantly to this protective effect.

The gallbladder is an organ that produces bile to help break down fats; consuming a very high fat diet requires more bile, which can strain the gallbladder and increase the risk of gallstones. It is believed that caffeine may help to stimulate contractions in the gallbladder and increase the secretion of cholecystokinin, a hormone that speeds the digestion of fats. Animal studies show a protective effect of caffeine from deterioration in the brain. Caffeine has a similar action to the medication theophylline, which is sometimes prescribed to treat asthma.

They both relax the smooth muscles of the lungs and open up bronchial tubes, which can improve breathing. Caffeine stimulates the release of a stress hormone called epinephrine, which causes liver and muscle tissue to release its stored glucose into the bloodstream, temporarily raising blood glucose levels.

However, regular caffeine intake is not associated with an increased risk of diabetes. In fact, cohort studies show that regular coffee intake is associated with a lower risk of type 2 diabetes , though the effect may be from the coffee plant compounds rather than caffeine itself, as decaffeinated coffee shows a similar protective effect. Caffeine toxicity has been observed with intakes of 1. Consuming grams at one time is believed to be fatal. Caffeine intake up to 10 grams has caused convulsions and vomiting, but recovery is possible in about 6 hours.

The main difference between the caffeine in coffee and tea is that tea has a lot less of it. A strong cup of coffee can provide — mg of caffeine, while a cup of tea may provide 20—60 mg. Caffeine blocks adenosine in the brain, an inhibitory neurotransmitter that promotes sleepiness. Tea contains much less caffeine than coffee, thereby providing fewer stimulating effects. Theophylline and theobromine are both related to caffeine and belong to a class of organic compounds called xanthines.

Theophylline relaxes smooth muscles in the airway, making breathing easier while also stimulating both the rate and force of heart contractions. Theobromine can also stimulate the heart, but it does have a mild diuretic effect and improves blood flow around the body, leading to a net reduction in blood pressure.

Cocoa beans are also good sources of these two substances 3. The amounts of these substances in a cup of tea are very small though, so their net effect on the body is probably negligible.

Some of the caffeine you ingest is metabolized into theophylline and theobromine, so every time you consume caffeine you will indirectly increase your levels of these two caffeine metabolites. Theophylline and theobromine are organic compounds related to caffeine and found in small amounts in tea.

They stimulate the body in several ways. It is a unique type of amino acid called L-theanine. It is mainly found in the tea plant Camellia sinensis. Like caffeine, theophylline and theobromine, it can enter the brain by crossing the blood-brain barrier.

In humans, L-theanine increases the formation of brain waves called alpha waves, which are associated with alert relaxation. This is perhaps the main reason for the different, milder buzz that tea generates 4.

L-theanine may affect neurotransmitters in the brain, such as GABA and dopamine 5. Some studies have suggested that L-theanine, especially when combined with caffeine, can improve attention and brain function 6 , 7. Tea contains an amino acid called L-theanine, which increases the production of alpha waves in the brain. L-theanine, in combination with caffeine, may improve brain function.

Tea may be a suitable alternative for those who are sensitive to the high amounts of caffeine in coffee. Due to the L-theanine and its effect on alpha waves in the brain, it may also be a better choice than coffee for those who need to concentrate for long periods.

I personally feel pretty good when I drink tea green tea , in my case. For me, tea looks like the best choice when doing work on the computer or studying, while coffee is better suited for physical activities like working out.