Coffee lovers are everywhere, as evidenced by the flocks of people flooding every Starbucks branch. As of 2000, an estimate of 54% of adults in the United States are found to be daily coffee-drinkers. While it is well-known that coffee helps wake a person up to get him alert enough to face the day, are there negative effects from caffeine?
Caffeine, a stimulant of the nervous system, is found not just in coffee beans, but also in chocolate and tea leaves. It is also popularly added to carbonated drinks and even over-the-counter drugs, particularly aspirin, cold remedies, weight control medication, and diuretics. Despite that though, about 75% of caffeine consumption in the U.S. comes directly from coffee.
How does caffeine work? Typically, it stimulates a person’s central nervous system when it clocks adenosine. Adenosine is a neurotransmitter normally giving a person a calming effect. When caffeine blocks the neurotransmitter, it results in a neural stimulation which calls the adrenal glands to produce adrenaline, the well-known hormone for “fight or flight.” This causes the person’s heart rate to increase, pupils to dilate, and muscles to tighten up, while glucose gets released into his blood stream, giving him an energy boost, known by laymen as the “caffeine buzz.”
In addition to that blockage, caffeine also enhances the production of dopamine. This helps activate the feeling of pleasure in certain parts of the brain, and is believed to be part of the reason why many people get addicted to coffee.
Overall, the added energy given by caffeine has been found to have improved effect on athletic performance, at least as far as endurance goes. When caffeine is consumed before exercising, it is found to extend endurance for moderate aerobic activity. Even distance swimmers and runners have reported longer endurance after consuming coffee.
Despite these seemingly positive effects brought about by caffeine, there have also been risks documented for the substance, not only for athletic performance but also in terms of daily consumption.
One of the negative effects of caffeine is that it can result in restlessness, irritability, and headaches. The elevated heart rate may also increase blood pressure. When a person gets used to consuming caffeine daily, his body may start to require greater amounts in order to achieve the same level of effects. As such, it turns the body into one in a perpetual state of hormonal emergency, which is obviously not too healthy.
In addition to being a stimulant, caffeine also works as a diuretic, causing a loss of fluid, which may result in some dehydrating effects. This means that despite the positive physiological push that caffeine gives, it is not too advisable for fitness regimes requiring fluids for transfer of nutrients, such as in resistance training. Muscular growth requires the transport of nutrients via bodily fluids, so having the diuretic effect from caffeine may hinder the results you are looking for. Also, this effect is risky for people exercising in extremely hot environments, as it can contribute to excessive loss of fluids.
Of course, the most crucial long-term issue associated with regular caffeine intake is its effect on sleep. Caffeine has a half-life of about 6 hours in the human body. This means that a big mug of coffee, perhaps with 200mg of caffeine, taken at 4PM, will still have half of that in the person’s body, or 100mg, by 6PM. After another 6 hours, at 4AM, there is still 50mg of caffeine left in the body. A person may be able to sleep, but with the caffeine still in the system, he may not be able to get the best quality of sleep. For individuals who have to get up at a certain time for work or any other responsibility, they may wind up adding more caffeine to keep them awake enough to face the day, resulting in a vicious cycle of caffeine consumption.
Overall, the benefits of caffeine in jolting a person awake may be real, and the resulting energy boost prior to exercising may be considered an advantage. However, the risks documented, though mostly associated with extremely high consumption, should give you something to think about. The good news is that one to two cups a day falls in the moderate coffee drinking category, and is still considered by the American Heart Association as not having any real harmful effect. Just to be on the safe side, be sure to practice moderation, as is the key to consumption of just about everything else.
