What is Caffeine?
Caffeine is a naturally occurring central nervous system stimulant most commonly found in coffee, tea, and cacao plants. When it is consumed, caffeine is quickly absorbed into the bloodstream.
Caffeine works by stimulating the central nervous system and speeds up almost all bodily functions. It can increase:
- Heart rate
- Blood pressure
- Respiration rate
- Stress hormones
- Kidney and bladder activity
Caffeine Facts
Caffeine has been found to improve mood and cognitive function. It generally contributes to feelings of alertness and happiness, improves short-term memory recall and reaction time, and prevents fatigue.
When it comes to exercise, caffeine may improve performance by increasing the use of fat as fuel. It does this by increasing fatty acid oxidation and prolonging the glucose stored in muscles, potentially delaying the time it takes your muscles to reach exhaustion and prolonging the length of your exercise.
However, too much caffeine may cause tenseness, nervousness, headaches, hand tremors, inability to concentrate, insomnia, stomach irritation, and irregular heartbeat in some individuals.
The more serious risks of caffeine are mostly related to heavy consumption.
How Much Caffeine Is Safe?
The United States Food and Drug Administration (FDA) recommends limiting caffeine intake to less than 400 mg per day.
Caffeine affects everyone differently. Some research has shown that interindividual differences in caffeine response may be partly due to variations in genes.
Studies have shown that regular coffee consumption is associated with a decreased risk of developing cardiovascular disease, hypertension, and heart failure. However, the research is inconsistent with regard to coffee consumption and the risk of developing coronary heart disease.
It is important to note that people have different tolerances and responses to caffeine. Not everyone will react to caffeine the same. Even a small amount, such as 40 mg, is enough to make some people’s hands shake.
Caffeine Sources
While coffee is the most common source of caffeine, many other forms exist. For reference, energy drinks contain 100-200 mg of caffeine, some pre-workout supplements contain up to 500 mg of caffeine, and an 8 oz cup of coffee contains roughly 100 mg of caffeine.
Caffeine-Free Energy
Caffeine has become a hero to many, giving a great kickstart to your morning or helping power through that afternoon slump. There are plenty of ways to energize without consuming caffeine if you are someone who tends to overconsume. Some ideas include:
- Take a brisk 10-minute walk
- Get a good night’s sleep
- Eat regular, healthful meals
- Meditate & de-stress
- To stay alert when studying try waking up your senses:
- Green sour apples
- Hot herbal tea with a strong smell
- Peppermint
- Chewing gum
References
dePaula J, & Farah A. Caffeine Consumption through Coffee: Content in the Beverage, Metabolism, Health Benefits and Risks. 2019. Beverages, 5(2), 37. https://doi.org/10.3390/beverages5020037
Ruxton HS. The impact of caffeine on mood, cognitive function, performance and hydration: a review of benefits and risks. 2008. Nutrition Bulletin Volume, 33: 15-25. https://doi.org/10.1111/j.1467-3010.2007.00665.x
Kapellou A, King A, Graham C.A.M, Pilic L, & Mavrommatis Y. Genetics of caffeine and brain-related outcomes – a systematic review of observational studies and randomized trials. 2023. Nutrition reviews, 81(12), 1571–1598. https://doi.org/10.1093/nutrit/nuad029