What does caffeine do to your body? A recent review of the literature reports on the many effects that caffeine can have on you. A key mechanism of action is to block adenosine receptors, which results in an increase in dopamine, glutamate, and noradrenalin. It effects your cardiovascular system by increasing the blood pressure and heart rate. And, it can improve motor activity and alertness by working on the central nervous system. However, higher does can produce symptoms of anxiety.
Studies also show that the adenosine receptor genes have a role in producing anxiety. The evidence suggests that some people may have a higher risk of anxiety disorders and that caffeine may make them more susceptible.
The Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association, recognizes caffeine-induced anxiety disorder as a condition in which caffeine interferes with daily functioning. To meet the criteria for this diagnosis, a person must have symptoms of anxiety directly caused by the consumption of caffeine.
The DSM-5 has also proposed criteria for caffeine use disorder, in which all three of the following criteria must be met:
- symptoms of caffeine withdrawal
- persistent desire or unsuccessful effort to control caffeine use
- use of caffeine despite harm
Although this is not yet an official DSM diagnosis, it provides researchers with a framework to conduct further studies.
Symptoms of caffeine-induced anxiety
The symptoms of consuming too much caffeine and the symptoms of anxiety can overlap.
Symptoms of using too much caffeine include:
- nausea
- dizziness
- dehydration
- headaches
- restlessness
- rapid heartbeat
- insomnia
Symptoms of anxiety typically include:
- feelings of fear, dread, and uneasiness
- excessive worry
- sweating
- restlessness
- tenseness
- rapid heartbeat
Overconsumption of caffeine can produce anxiety symptoms. In turn, anxiety may worsen with the consumption of caffeine.
Consuming caffeine safely
Studies show that moderate consumption of caffeine can produce some health benefits. These include improvement in mental alertness, concentration, fatigue, and athletic performance. Other benefits may include weight loss, lower risk of diabetes, reduced risk of Parkinson’s disease, and reduced risk of cancer.
The FDA issued guidance in 2012 stating that for healthy adults, caffeine consumption at less than 400 mg/day is not associated with adverse effects.
Results from a 2014 survey in the U.S. found that for all ages combined, the average intake of caffeine from all beverages is 165 milligrams (mg)/day. This is about the amount in 1–2 cups of regular coffee. The FDA states that any intake up to 400 mg of caffeine a day should not lead to adverse health effects. This is equivalent to about 3–4 cups of coffee.
Some people with certain health conditions should check with their doctor about whether to avoid or limit caffeine. These include people who:
- are pregnant
- are breastfeeding
- have insomnia
- experience migraines or chronic headaches
- have anxiety
- have stomach disorders such as ulcers
- have an irregular heart rate or rhythm
- have high blood pressure
- take certain medications including stimulants, some antibiotics, asthma medications, and heart medications
- are children and teenagers
Youth and energy drinks
One concern is the popularity of energy drinks with youth. Energy drinks typically have high levels of caffeine and sugar. There may be concerns about combining alcohol and energy drinks high in caffeine.
The first step in making informed decisions is for a person to be aware of the caffeine content of beverages. Label reading and daily planning can help avoid the adverse consequences of excessive caffeine consumption. People who want to reduce or limit their caffeine consumption should do so gradually. This will help avoid symptoms such as headache, fatigue, irritability, drowsiness, difficulty concentrating, and nausea.
High caffeine products
The caffeine content of beverages was measured in the 2014 survey cited above .The researchers grouped them into several general categories:
Beverage, Caffeine Content (mg/fluid ounce)
- Regular coffee, 4-21
- Espresso, 47-63
- Decaffeinated coffee, 0.25
- Carbonated soft drinks, caffeinated, regular or diet, 2-7
- Tea, caffeinated, regular or diet, 1-8
- Energy drinks, 3-20
- Energy shots, 40-70
- Chocolate milk, 0.2-2
There were limitations in determining the amount of caffeine in the beverages included within the table. The study authors state that while most commercially available drinks have caffeine content listed on the label, for teas and coffees that are made to order, the content can vary widely. The caffeine content can depend on the origin of the crop, processing, and preparation.
Alternatives to caffeine
Many people rely on the jolt of energy that caffeine provides to get them going in the morning. This can sometimes come with negative consequences, such as development or worsening of anxiety symptoms.
Decaffeinated coffee or tea may be a good alternative for many people. These beverages tend to have a similar flavor; however, they may not provide the energy boost that caffeine does. Once a person successfully weans themselves from caffeine, however, these can be a calming choice.
There is a vast array of herbal teas available. They are popular throughout the world and have numerous health benefits.
Some people find that exercise can be a great way to start the day. A walk or run outside, or a jog on the treadmill indoors, can be a good way to get blood flowing and clear brain fog. Drinking water can also help people wake up.
Final thoughts
There is an association between overconsumption of caffeine and anxiety. The effects of having too much caffeine can mimic symptoms of, or worsen anxiety. People who experience caffeine-induced anxiety should avoid or reduce their consumption of caffeine. It is important to be aware of the caffeine content of many commonly consumed beverages. With careful planning, you can make informed choices to reduce or avoid the use of caffeine.