In addition, there have been several reports of rhabdomyolysis related to excessive caffeine intake, although this is relatively rare ( 26, 27, 28, 29). It's important to point out that not everyone gets caffeine withdrawal symptoms - and if you do, the caffeine withdrawal symptom severity will depend on how much caffeine you were drinking. As a rough rule, they typically last between two and nine days, peaking after one or two days of abstinence. For heavy caffeine drinkers who stop abruptly, the body can take even longer to readjust. Caffeine is a central nervous system stimulant. It works by stimulating the brain. Caffeine is found naturally in foods and beverages such as coffee, tea, colas, energy and chocolate. Botanical sources of caffeine include kola nuts, guarana, and yerba mate. Caffeine is also available in prescription and non-prescription medications. Sugar, syrups, whole milk and cream add calories and saturated fat that could cause weight gain and increase cholesterol levels

Energy drinks. 1 cup or 8 ounces of an energy drink contains about 85 mg caffeine. However the standard energy drink serving is 16 ounces, which doubles the caffeine to 170 mg. Energy shots are much more concentrated than the drinks; a small 2 ounce shot contains about 200 mg caffeine. Learn more about energy drinks.Fortunately, caffeine’s effect on blood pressure seems to be temporary. Also, it seems to have the strongest impact on people who aren’t used to consuming it. ( 35, 36) Caffeine is a natural chemical with stimulant effects. It is found in coffee, tea, cola, cocoa, guarana, yerba mate, and over 60 other products. Does how you drink it make a difference? In short: yes. Darker roasts, as well as being lower in caffeine, tend to contain fewer antioxidants and lower levels of chlorogenic acid, a compound that can protect the body against inflammation and cell damage. When you grind the beans doesn’t matter (unless you prefer that fresh-ground flavour), but how much you grind them probably does – a finer grind releases more polyphenols, giving fine-ground brews slightly more beneficial effects. Most OTC medications used for mental alertness contain 200 milligrams of caffeine per tablet or capsule. The usual maximum recommended dose of OTC caffeine is no more than 200 mg every 3-4 hours, or 1600 mg per day. Caffeine can cause insomnia so people often avoid it in the evenings so that they can sleep properly. The half-life of caffeine is around 5 hours, meaning that after a cup of coffee at 6pm, an individual will still have half the caffeine left in their body at 11pm, and a quarter at 4am, disrupting sleep. Individuals vary in their reaction to caffeine, so the half-life could be much longer or shorter than 5 hours.

Addicott, M. A. and Laurienti, P. J. A comparison of the effects of caffeine following abstinence and normal caffeine use. Psychopharmacology (Berl) 2009;207(3):423-431. View abstract. Bu FL, Feng X, Yang XY, Ren J, Cao HJ. Relationship between caffeine intake and infertility: a systematic review of controlled clinical studies. BMC Womens Health. 2020;20(1):125.

Bruce, C. R., Anderson, M. E., Fraser, S. F., Stepto, N. K., Klein, R., Hopkins, W. G., and Hawley, J. A. Enhancement of 2000-m rowing performance after caffeine ingestion. Med.Sci.Sports Exerc. 2000;32(11):1958-1963. View abstract. One cup (240 mL) of decaf coffee contains 1–50 mg of caffeine, depending on the brand and serving size. That’s less than half the amount of caffeine in a regular cup. Some medical conditions may interact with caffeine. Tell your health care provider if you have ANY medical conditions, especially if any of the following apply to you: These results suggest that it’s important to pay attention to both the amount and timing of caffeine to optimize your sleep. Summary Bucher, H. U. and Duc, G. Does caff

Bell, D. G., McLellan, T. M., and Sabiston, C. M. Effect of ingesting caffeine and ephedrine on 10-km run performance. Med.Sci.Sports Exerc. 2002;34(2):344-349. View abstract.People most commonly use caffeine for mental alertness, headache, migraine, athletic performance, memory, and obesity. It is also used for asthma, gallbladder disease, ADHD, low blood pressure, depression, and many other conditions, but there is no good scientific evidence to support most of these other uses. In small doses, caffeine can make you feel refreshed and focused. In large doses, caffeine can make you feel anxious and have difficulty sleeping.

Although coffee and tea are the most concentrated sources of caffeine, it is also found in soda, cocoa, energy drinks and several types of medication. Barrington, K. J. and Finer, N. N. A randomized, controlled trial of aminophylline in ventilatory weaning of premature infants. Crit Care Med. 1993;21(6):846-850. View abstract. Caffeine can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking caffeine along with phenylpropanolamine might cause too much stimulation and increase heartbeat, blood pressure, and cause nervousness.

References

Instead of giving up caffeine completely, some people find it easier to switch to lower-caffeine varieties of tea and coffee or choose drinks with lower caffeine content," says Hyams. "If you have a more severe dependency on caffeine, it is suggested that you should aim to reduce your caffeine intake slowly instead of giving up caffeine all at once." Felbamate is used to control certain types of seizures. Caffeine might lower the effects of felbamate. Taking caffeine with felbamate might reduce its effects and increase the risk of seizures.