Are Caffeinated Beverages Efficient Thirst-Quenchers?
Despite what you may see on Coca-Cola or Starbucks commercials, caffeinated beverages are inefficient thirst-quenchers. Your healthcare professional likely advises drinking around 8 cups of water per day. Drinking caffeinated beverages increases your water deficit. Some people suffer from chronic migraines or vertigo. Does caffeine exacerbate or reduce symptoms?
Caffeine is a chemical with many biological reactions. People tend to focus only on the one they favor. For example, you may hear, “I can’t function until I have my morning coffee” or “I need a sports drink so I can focus.” This scientific overview will help you put caffeine in proper context. Then you can determine whether there is a need to cut back or eliminate it from your diet.
The Chemical Process
I love fresh-brewed black coffee. But I recognize that caffeine is both a stimulant and sedative. Caffeine is also a diuretic. This means it drains fluids from the body, drying skin and causing other complications. With dehydration as the common denominator, caffeine intolerance can mimic symptoms of hangover.
Though dosages vary, caffeine can affect the human body in the same way as nicotine and cocaine. Taken in sufficiently small doses, these methylxanthines, or plant alkaloids, alter the function of the nervous system. The human body may adapt to the neurotoxic alkaloids, continuing to work, seemingly unaffected, despite interference. It does so simply by increasing production of indigenous adenosine (a-DEN-oh-seen).
Such adaptation, however, can result in painful withdrawal headaches during cessation or resumption as neurochemicals readjust. In the absence of caffeine, a regular user is oversensitive to adenosine and undersensitive to excitatory neurotransmitters. A caffeine consumer adapts to caffeine exposure but not to its deficiency. 
Although caffeine fulfills some of the criteria for drug dependence and shares with amphetamine and cocaine a certain specificity of action on the cerebral dopaminergic system, it does not act on the dopaminergic structures related to reward, motivation, and addiction. 
The molecularly similar shape of caffeine allows it to fit into and block adenosine receptors that are embedded within the surface membranes of neurons. Adenosine is a neuromodular that regulates serotonin, norepinephrine, dopamine and acetycholine. Neurologists or psychologists might, therefore, treat migraines with serotonin and norepinephrine uptake inhibitors—also prescribed as antidepressants. Interestingly, dizziness and headache are included in the list of possible drug side effects.
High doses of caffeine induce negative effects such as anxiety, restlessness, insomnia, and tachycardia. Adenosine supplements could be prescribed to treat supraventricular tachycardia (irregular heartbeat) or off-label conditions. [1-4]
By blocking adenosine, caffeine reverses the effect, causing pain where it is normally suppressed.
Depending upon where it is located, adenosine functions as a tranquilizer, painkiller, or even pain inducer. By blocking adenosine, caffeine reverses the effect, causing pain where it is normally suppressed and exciting neurochemicals that should be tranquilized. Adenosine is a vasodilator, which can bring on peripheral pain. When blood volume is reduced, less oxygen reaches the brain, triggering migraines. Caffeine is also a vasodilator, constricting oxygen-carrying arteries.
Migraines and Caffeine
Caffeine overconsumption or withdrawal can cause migraines. Understanding how caffeine interacts with adenosine, provides rationale for the use of caffeine in migraine-formula pain killers. The goal is to block and reverse the cause of pain. This creates a conundrum if the migraine is caused by caffeine in the first place.
A high caffeine dosage is considered to be 250–500 mg (3-6 cups of coffee).  Consumption of 500–1000 mg can be life-threatening. But a so-called high dose varies between individuals as neurochemicals become deregulated. Sometimes people who formally consumed relatively high amounts of caffeine can develop a sensitivity after a period of abstinence. Neurotransmitters malfunction, and those malfunctions generate migraine symptoms.
Average Caffeine in 8-Ounce Beverages
A shortage of serotonin receptor activation prevents serotonin from appropriately blocking pain. A shortage of acetylcholine, a neurotransmitter essential to vision, in the retinas may cause the visual disturbances associated with migraine. A dopamine shortfall may cause the emotional and behavioral effects associated with migraine. A norepinephrine shortage causes the symptoms of sympathetic hypofunction associated with primary headache.
Caffeine Overlooked as Pain and Disequilibrium Contributor
The news is not entirely bleak for caffeine. It is a potent stimulant that may increase productivity. Coffee contains niacin and antioxidants; it has been associated with a lower risk of type 2 diabetes and may be used as prophylactic for cardiovascular disease. Green tea protects against various cancers.
Practically everyone drinks coffee in the morning. Caffeine-packed energy drinks are consumed throughout the day. Caffeine is found in green tea, chocolate, and cola soft drinks. In a 2005 survey study of the U.S. general population, 87 percent of 18,081 subjects reported dietary caffeine intake and 71 percent said they drank coffee. [4,5] With such widespread use, most people—including some physicians—find it difficult to believe that caffeine could be causing migraines and disequilibrium in select patients, while other patients who consume higher doses appear unaffected. Migraines can be hereditary or an underlying psychosis may be suspected.
Isolating Caffeine As a Health Problem
There can be several migraine exacerbators; some only trigger a reaction when combined with another, for example, caffeine and stress or chocolate with nuts. It is wise to first check with your doctor to rule out other causes for chronic headaches such as tumors and aneurisms.
Blood tests can identify food allergies. A way to personally determine if you have a caffeine sensitivity (or addiction) is to pick a time when you have a few of days off from work and go “cold turkey for a day or two.” Stop consuming caffeine; drink water or perhaps a natural juice cleanse if approved by your health care provider and follow with probiotics. There may be some withdrawal symptoms for a couple of days. Cessation can even cause migraines.
You may find that you are not addicted and can function well without caffeine. In some cases you might need to wean yourself off with tea. After abstinence for 90 days or longer, find another appropriate time when mental acuity may not be required. (Perhaps a long weekend.) Drink two 16 oz glasses of caffeinated iced tea or two 8 oz cups of coffee and see how you feel the next couple of days. If there is no effect with two servings, pick different weekend and try four servings.
If you feel headaches, develop extra-dry skin, lose equilibrium and/or have digestive disturbances, a possible trigger is evident. Because caffeine may be present in other foodstuffs, the tolerance level is not an exact science. Endeavor to stay far beneath your personal limit or eliminate caffeine completely from your diet.
You may later discover that intolerance is reliant upon a secondary factor or a completely different trigger; this can make you doubt your initial conclusions. Be patient and keep a journal to discuss findings with your healthcare provider.