Milk being poured in a coffee cup containing caffeine

Caffeine and Coffee: Benefits, Safety, and Side Effects

Coffee is one of the most popular and consumed beverages worldwide and caffeine is its best-known component. Coffee is slightly acidic and somewhat bitter and acts as a mild stimulant because of its caffeine content. Caffeine operates on the central nervous system by blocking the action of adenosine, a neurotransmitter that promotes relaxation and sleepiness. By inhibiting adenosine’s effects, caffeine fosters a heightened state of alertness and wakefulness. If you have developed a dependence on caffeine, an abrupt cutback can cause caffeine withdrawal. Symptoms of caffeine withdrawal begin 12 to 24 hours after the last intake and can last two to nine days.


Caffeine offers a range of benefits that have endeared it to countless individuals. While these advantages can be compelling, it’s essential to consume it in moderation and be aware of individual tolerance levels.

  • Enhance Alertness and Cognitive Function: Caffeine may enhance alertness and cognitive performance. It improves concentration, memory, and problem-solving skills, making it an invaluable tool for individuals seeking to boost productivity, especially during long working hours or when combating fatigue.
  • Physical Performance: Athletes and fitness enthusiasts use caffeine as an ergogenic aid. It can increase physical endurance by mobilizing fatty acids from fat tissues, making them available for energy production. This helps delay fatigue, making caffeine a popular choice for pre-workout supplementation.
  • Mood Elevation: Caffeine has mood-enhancing properties. It promotes the release of dopamine and norepinephrine, which can lead to improved mood and a sense of well-being. Many individuals rely on it to alleviate mild depression and anxiety symptoms.
  • Antioxidant Properties: Coffee, in particular, is rich in antioxidants, which have various health benefits. Antioxidants help protect the body from oxidative stress and reduce the risk of several chronic diseases, including certain types of cancer.
  • Pain Relief: Caffeine can help relieve headaches and migraines and may even improve the efficacy of other pain medications.

Safety Concerns

Overconsumption can lead to several safety concerns, both in the short and long term.

  • Daily Limits: The recommended daily intake varies depending on the individual and factors like age, weight, and sensitivity. However, for most healthy adults, up to 400 milligrams (about 4 cups of brewed coffee) per day is generally safe. Exceeding this limit can lead to adverse effects, such as jitteriness, increased heart rate, and insomnia. Keep in mind that cup sizes and coffee strengths can vary. A typical eight-ounce cup has about 80 to 100 milligrams of caffeine in coffee, according to the FDA. But at Starbucks, a ‘tall’ (12 ounce) medium-roast contains around 235 milligrams of caffeine in coffee – about the same amount as a triple shot of espresso. 
  • Sleep Disruption: Caffeine is notorious for disrupting sleep patterns. Its stimulant properties can keep individuals awake at night, leading to sleep deprivation and its associated health risks. It’s advisable to avoid caffeine intake in the afternoon and evening to ensure a good night’s sleep.
  • Anxiety and Nervousness: Overconsumption can trigger or exacerbate symptoms of anxiety and nervousness, including restlessness, increased heart rate, and even panic attacks in extreme cases. Those with anxiety disorders should exercise caution when using caffeine.
  • Dependence and Withdrawal: Consumption can be habit-forming, leading to physical and psychological dependence. Abrupt intake can cause withdrawal symptoms like headaches, fatigue, irritability, and depression. Reducing intake gradually can help mitigate these effects.
  • Cardiovascular Effects: Excessive consumption can lead to an increased heart rate, palpitations, and, in some cases, even irregular heart rhythms. People with heart conditions should consult their healthcare providers before increasing caffeine intake.
  • Pregnancy and Fertility: High caffeine intake during pregnancy may associate with a higher risk of miscarriage and preterm birth. Most medical providers will recommend that pregnant women limit their intake to about 200 milligrams per day.
  • Bone Health: Excessive caffeine consumption may lead to calcium absorption, potentially affecting bone health. However, this effect can dwindle with a diet rich in calcium and vitamin D.

Side Effects

In addition to the safety concerns, caffeine can have a range of side effects, especially when consumed in excessive amounts or by individuals with low tolerance levels.

  • Insomnia: One of the most common side effects of caffeine is difficulty falling asleep and staying asleep. Consuming caffeine late in the day can disrupt the sleep-wake cycle and lead to insomnia.
  • Jitters and Restlessness: High doses of caffeine can cause jitteriness and restlessness, making it difficult for individuals to relax or concentrate.
  • Increased Heart Rate and Blood Pressure: Caffeine’s stimulant properties can lead to an increased heart rate and elevated blood pressure. In individuals with pre existing heart conditions, this effect can be dangerous.
  • Digestive Distress: It can irritate the stomach lining and lead to digestive discomfort, including acid reflux, indigestion, and gastrointestinal upset.
  • Headaches: Ironically, caffeine withdrawal can lead to headaches, often referred to as “caffeine withdrawal headaches.” These can be quite painful and are typically relieved by consuming more.
  • Addiction and Tolerance: As mentioned earlier, caffeine can be habit-forming. Regular consumption can lead to tolerance, meaning that over time, more caffeine is required to achieve the same stimulating effects.
  • Nervousness and Anxiety: Excessive intake can cause or worsen feelings of nervousness and anxiety. This effect is particularly pronounced in individuals who are sensitive to caffeine.

Caffeine is a multifaceted compound with a rich history of use by cultures around the world. It offers a range of benefits, from increased alertness and cognitive performance to mood enhancement and potential health benefits. 


Author: Bree Maloney, Director of Communications

Picture of Bree Maloney in a black jacket

The information provided is for general interest only and should not be misconstrued as a diagnosis, prognosis or treatment recommendation. This information does not in any way constitute the practice of medicine, or any other health care profession. Readers are directed to consult their health care provider regarding their specific health situation. Marque Medical is not liable for any action taken by a reader based upon this information.
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