what does caffine do to your body?

Caffeine stimulates the central nervous system first at the higher levels, the cortex and medulla, and finally the spinal cord at higher doses. Mild cortex stimulation appears to be beneficial resulting in more clear thinking and less fatigue. Caffeine has been shown to improve attention in a study which simulated night driving (Leinart, 1966). The onset of the effect of caffeine occurs within one hour and lasts for three to four hours (Baker, 1972).

The equivalent of one or two cups of coffee (150 to 250 mg of caffeine) is sufficient to induce adverse effects. The occurrence of hyperesthesia, an unpleasant sensory sensation, can be stimulated by large doses of caffeine.

The medullary, respiratory, vasomotor and vagal centers are stimulated by caffeine. This effect is due to an increased sensitization to carbon dioxide but needs large doses to elicit this effect, 150 to 250 mg, parenterally. The spinal cord is stimulated at higher doses and convulsions and death may result. More than 10 g are needed for such toxicity to occur in man (Ritchie, 1975).

Stimulation of the CNS is followed by depression (Klein and Salzman, 1975), although the effect is small at low doses e.g. a single cup of coffee. After two hours, Klein reported that males (but not females) showed a lower CNS stimulation compared to placebo. The post stimulation "let down" with caffeine results in fatigue and lethargy and the constant stimulation caused by chronic caffeine dosing could be disastrous (Abrams, 1977; Dowell, 1965).

Children, because of their smaller size, are more susceptible to caffeine. One report noted that hyperactivity and ir~somnia observed in children could be attributed to excess caffeine intake from cola drinks (Consumer Research, 1973). According to Dr. Page, "There is no doubt that children should be kept from using coffee and the popular caffeine containing soft drinks." (Abrams, 1977).

Caffeine's effect on the cardiovascular system is less profound than its central nervous system action. Its direct stimulatory effect on the heart may be neutralized by its central vagus stimulation. The direct effect predominates at very large doses with tachycardia and, eventually, arrythmias resulting. Caffeine's ability to potentiate cyclic AMP can explain its ability to potentiate ionotropic responses to B-adrenergic agonists and glucogon (Ritchie et al, 1975).

Although caffeine dilates blood vessels by a direct action, its central effect is one of constriction. At higher doses, the dilating effect is apparent (Peach, 1972; Poisner, 1973).

Similarly, because its direct and central effects are antagonistic, the resultant effect of caffeine on blood pressure is unpredictable. The net effect is usually of less than 10 mm of Hg in blood pressure (Ritchie et al., 1975). Caffeine's purported efficacy in hypertensive headaches may be due to a decrease in blood flow as a result of the increased cerebral resistance (Ritchie et al., 1975).

Caffeine also stimulates releases of catecholamines from the adrenal medulla and norepinephrine is released from nerve endings in the isolatA heart (Bellett et al., 1971). .

It has been shown that prolonged augmentation of gastric 'secretion results from caffeine administration and that ulcer patients have sustained elevation of acid as opposed to normals (Ritchie et al., 1975).

Although a dose of approximately 10 g or more taken orally can be fatal, an oral (3.2 g IV) one gram dose will cause adverse effects (Gleason et al., 1969). The toxic effects are due to CNS and circulatory system stimulation and include some well recognized prominent symptoms in addition to those which can result at high doses or in hypersensitive persons: insomnia, restlessness, excitement, tinnitus, flashes of light, quivering muscles, tachycardia, extrasystoles, and even low grade fever and mild delirium have been observed.

Harrie (1970) described a patient whose constant headaches were due to excessive caffeine consumption. He states, "I suspect that the condition is much more common than supposed and could well be one of the more frequent causes of chronic recurrent headache." Headaches can also be precipitated by caffeine withdrawal especially by those who have the "habit".

Although caffeine is well absorbed when taken orally, its absorption may be erratic because of its low solubility and because it may cause gastric irritation. Caffeine is principally metabolized with only 10 percent excreted in the urine unchanged (Ritchie et al., 1975).

Caffeine has a physiological half-life of three and a half hours (Parsons anjd Neims, 1978) to six hours (Aranda et al., 1979). Its physiological effects are observed in less than one hour (Parsons and Neims, 1978). Infants do not metabolize caffeine as well as adults and thus have a half-life of about four days (Aranda et al., 1975). Certainly, continuous ingestion of caffeine by infants can be dangerous. If a cup of coffee is consumed by an adult six or seven times a day it would result in a high steady concentration of caffeine in the blood. As little as four cups a day can result in appreciable omnipresent amounts of caffeine in the body.

Caffeine can accumulate in severe liver disease (Stratland, 1976) when its half-life can increase to 96 hours. If these patients drink coffe(~ they should be closely monitored.

Caffeine is known to interact with other drugs resulting in a modified effect. For example, caffeine administered with nardil (an MAO inhibitor) caused headaches and high blood pressure (Pakes, 1979). This potentially dangerous interaction was first noted by Berkowitz et al., (1971) and implicated serotonin in the mechanism.

Caffeine and barbitol are antagonistic, with caffeine (in coffee) reducing the sleeping time induced by barbitol. Decaffeinated coffee had no effect (Aeschbacher et al., 1975). In another study, caffeine resulted in reduced sleeping time which was counteracted by pentobarbitol in hospitalized patients (Forrest et al., 1972).

caffine produces much harsh effects on nervous system.

Actually human nervous system consists of many wires called neurons,These wire conduct impulses or nerve messages in the body.

one of the nerve transmission method is "SYNAPTIC TRANSMISSION"

synapsis is a gap between two wires or neurons (the axon of one neuron and the dendrite of other or in

simple words we can say head of one and end of other)

the message is in the form of small vesicles which have to pass the pre synaptic membrane of one nueron with the help of neuro transmitter and want to reach the paost synaptic membrane of other neuron.

wat caffine does is it get accumulated at the presynaptic membrane blocking the transmission of nerve impulse.

and if it prolonged then it cause many brian disease which may be fatal.

Caffeine is considered a stimulant drug. It stimulates the Central Nervous System through its neural transmitters. The caffeine stimulates nerve cells within the body.

come ON mahad that just not a good or true answer.

What the people above you said was also all true. And drinking coffee makes the toes tngle and it make me feel good. It doesn't just induce hypertension

Jeez

Caffeine is considered a stimulant drug. It wakes up your nerve to make you stay awake.

It's a diuretic. Caffeine makes you urinate more often, just like alcohol. It is also a simulant.

it increases your nerves and destroy your immune system if you drink many coffees everyday..even more, you can be addicted to coffee and then your organism will be valnurable...

nothing much

it just increase your blood pressure

it makesyou jumpy

makes you alert?