One thing to keep in mind is that caffeine may slightly raise blood pressure in some people. However, this effect is generally small (3–4 mmHg) and tends to fade for most individuals when they consume coffee regularly ( 32, 33, 34, 35). There is some evidence that people who drink a moderate amount of caffeine regularly might have a lower risk of:

Until recently, the Seventh-day Adventist Church asked for its members to "abstain from caffeinated drinks", but has removed this from baptismal vows (while still recommending abstention as policy). [282] Some from these religions believe that one is not supposed to consume a non-medical, psychoactive substance, or believe that one is not supposed to consume a substance that is addictive. The Church of Jesus Christ of Latter-day Saints has said the following with regard to caffeinated beverages: "... the Church revelation spelling out health practices (Doctrine and Covenants 89) does not mention the use of caffeine. The Church's health guidelines prohibit alcoholic drinks, smoking or chewing of tobacco, and 'hot drinks' – taught by Church leaders to refer specifically to tea and coffee." [283] these terms and conditions in full. If you disagree with any part of these terms and conditions, doWhat about when you actually drink it? “There’s a chance that the use of any supplement will carry a placebo effect,” says Dr Mike T Nelson, a researcher and performance specialist who recently co-wrote the International Society of Sports Nutrition’s position on coffee. “Many researchers use randomised, double-blinded, placebo-controlled trials to try to ferret that out. And if you look at some of the higher-dose caffeine studies and when they have been compared with a placebo, we still see a performance-enhancing effect of caffeine.” Caffeine in a dose dependent manner increases alertness in both fatigued and normal individuals. [56] The amount of caffeine in seemingly similar high-street coffees can vary significantly. Photograph: Wera Rodsawang/Getty Images The brewing temperature doesn’t matter that much; while some purists will claim that pouring boiled water directly on to your coffee grounds will “burn” the flavour, it seems to have little effect on the beneficial compounds inside.

The biosynthesis of caffeine is an example of convergent evolution among different species. [202] [203] [204]This causes a relative increase in other signaling molecules, such as dopamine and norepinephrine ( 5, 6).

High caffeine consumption in energy drinks (at least 1 liter or 320mg of caffeine) was associated with short-term cardiovascular side effects including hypertension, prolonged QT interval, and heart palpitations. These cardiovascular side effects were not seen with smaller amounts of caffeine consumption in energy drinks (less than 200mg). [79] Severe intoxication Reduced MS risk. Coffee drinkers may have up to a 30% lower risk of developing multiple sclerosis (MS). However, not all studies agree ( 48, 49). Rhabdomyolysis is a very serious condition in which damaged muscle fibers enter the bloodstream, leading to kidney failure and other problems. Commercially prepared coffee- flavoured milk beverages are popular in Australia. [236] Examples include Oak's Ice Coffee and Farmers Union Iced Coffee. The amount of caffeine in these beverages can vary widely. Caffeine concentrations can differ significantly from the manufacturer's claims. [226]Spilling the beans: How much caffeine is too much. Food and Drug Administration. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much. Accessed Sept. 20, 2019. However, at higher doses, these effects may become more pronounced, leading to anxiety and nervousness. The UK Food Standards Agency has recommended that pregnant women should limit their caffeine intake, out of prudence, to less than 200mg of caffeine a day– the equivalent of two cups of instant coffee, or one and a half to two cups of fresh coffee. [80] The American Congress of Obstetricians and Gynecologists (ACOG) concluded in 2010 that caffeine consumption is safe up to 200mg per day in pregnant women. [29] For women who breastfeed, are pregnant, or may become pregnant, Health Canada recommends a maximum daily caffeine intake of no more than 300mg, or a little over two 8oz (237mL) cups of coffee. [72] A 2017 systematic review on caffeine toxicology found evidence supporting that caffeine consumption up to 300mg/day for pregnant women is generally not associated with adverse reproductive or developmental effect. [73] Caffeine improves muscular strength and power, [66] and may enhance muscular endurance. [67] Caffeine also enhances performance on anaerobic tests. [68] Caffeine consumption before constant load exercise is associated with reduced perceived exertion. While this effect is not present during exercise-to-exhaustion exercise, performance is significantly enhanced. This is congruent with caffeine reducing perceived exertion, because exercise-to-exhaustion should end at the same point of fatigue. [69] Caffeine also improves power output and reduces time to completion in aerobic time trials, [70] an effect positively (but not exclusively) associated with longer duration exercise. [71] Specific populations Adults

Some textbooks state that caffeine is a mild euphoriant, [104] [105] [106] while others state that it is not a euphoriant. [107] [108] Increased urination is a common side effect of high caffeine intake due to the compound’s stimulatory effects on the bladder. Caffeine is a central nervous system stimulant that may reduce fatigue and drowsiness. [12] At normal doses, caffeine has variable effects on learning and memory, but it generally improves reaction time, wakefulness, concentration, and motor coordination. [52] [53] The amount of caffeine needed to produce these effects varies from person to person, depending on body size and degree of tolerance. [52] The desired effects arise approximately one hour after consumption, and the desired effects of a moderate dose usually subside after about three or four hours. [7]

Hillis DM, Sadava D, Hill RW, Price MV (2015). Principles of Life (2ed.). Macmillan Learning. pp.102–103. ISBN 978-1-4641-8652-3. Institute of Medicine (US) Committee on Military Nutrition Research (2001). "2, Pharmacology of Caffeine". Pharmacology of Caffeine. National Academies Press (US). Archived from the original on 28 September 2021 . Retrieved 15 December 2022. Some analog substances have been created which mimic caffeine's properties with either function or structure or both. Of the latter group are the xanthines DMPX [210] and 8-chlorotheophylline, which is an ingredient in dramamine. Members of a class of nitrogen substituted xanthines are often proposed as potential alternatives to caffeine. [211] [ unreliable source?] Many other xanthine analogues constituting the adenosine receptor antagonist class have also been elucidated. [212] A systematic review and meta-analysis from 2014 found that concurrent caffeine and L-theanine use has synergistic psychoactive effects that promote alertness, attention, and task switching; [57] these effects are most pronounced during the first hour post-dose. [57] Physical performance Coffee’s laxative effect has been attributed to the release of gastrin, a hormone the stomach produces that speeds up activity in the colon. What’s more, decaffeinated coffee has been shown to produce a similar response ( 19, 20, 21).