That morning cup of coffee had by some is a normal start to the day and is used to help wake us up and become alert for the work day ahead. But some that have used the effects of caffeine to improve their daily fitness routine, sporting event or running races are asking questions about their effectiveness and safety. The recent series of youth deaths adds to the concern about caffeine contained in energy drinks.
Caffeine has a number of effects on the body, some of which are potentially helpful and some harmful. It is the most widely used stimulant in the world found in a variety of plant sources as well as non-prescription medications.
It stimulates the central nervous system, heart rate, blood flow, improves alertness and reduces fatigue. It may also have a role in reducing the effects of chronic pain.
Despite being sometimes referred to as a nutritional ergogenic aid it has no nutritional value at all though it does help to release glucose and fat from storage into the blood.
However it does have problematic side-effects if taken in larger quantities. These include gastrointestinal distress, increased blood pressure, loss of appetite, anxiety, inability to focus on tasks, sleep difficulties, loss of judgment and, in some, irregular heartbeat, heart attack, stroke and possibly death.
Caffeine is absorbed fairly quickly and peaks in the body in about one to two hours. Its metabolic half-life is about three hours which means it takes about three hours for half of the ingested caffeine to be broken down and excreted in the urine.
One of the effects that recreational runners and fitness enthusiasts are concerned with is dehydration. Caffeine is a diuretic and if it causes dehydration during exercise there may be reason to avoid it. However in a number of recent studies using caffeinated beverages instead of pure caffeine found that caffeine that is ingested within the normal daily levels does not adversely alter sweat rates, urine loss or negative overall fluid loss. In fact one study found that even moderately larger doses of caffeine (three cups of coffee or eight cups of tea) resulted in a small fluid loss in those who had been deprived from their regular caffeine consumption for a period of time. Normal healthy adults will have no adverse effects in physical performance by drinking up to about 400 mg of caffeine. A normal 8 oz. Cup of coffee contains about 100 mg of caffeine (and up to 160 mg for specialty coffees), tea has about 20 mg, pop has about 40 mg for a 12 oz. can, and energy drinks have about 160 mg for every 16 oz. drink.
Athletes, and especially the younger population, must be aware of the deleterious effects of caffeine and other stimulants despite some mild benefits to physical performance measured in some adults studies recently. In the United States, the FDA has posted, and is investigating, a number of health-related incidents in youth from the consumption of caffeine-containing energy drinks including 92 illnesses and 13 deaths due to heart attack or suicide, 2 lasting disabilities, miscarriage, deafness, hemorrhage and a variety of other problems.
Parents and coaches should talk to their kids and discuss these issues. They may be unaware that caffeine is so widespread in many drinks but also in other sources such as herbal and nutritional supplements. Combining caffeine with other more deadly stimulants such as ephedrine and other drugs is also very important to discuss. Read labels, ask questions, but most importantly talk with your kids and to your family doctor.