Physiological Effects of Caffeine

Physiological effect of caffeine: (Note that the dose of caffeine needed to produce this effect and the severity of these effects will vary from person to person.)

(-) Caffeine usually raises blood pressure by contracting non-habitual user's heart and blood vessels. Effect usually disappears after 3-4 hours

(-) Caffeine alters the electrophysiological activity of the heart and increases conductivity at limited doses

(-) When ingesting large amounts of caffeine, the plasma concentration of homocysteine ​​(about 2 mmol / L) rises. This is a risk factor for heart disease.

Serum cholesterol levels may rise when you ingest (-) coffee. Cholesterol levels may increase by 0.5-0 mmol / L (20 - 40 mg / dL) if ingested more than 5 cups with no filter applied.

(-) Caffeine stimulates the secretion of gastric juice. It is sensitive to caffeine and may be affected by people of various degrees such as indigestion by acid, heartburn, abdominal pain, gas, constipation.

(-) Liver metabolism is affected by methylxanthines such as caffeine. It increases the level of cyclic AMP and decreases the content of branched and aromatic amino acids in plasma.

(-) Caffeine, especially over 300 mg (3 cups of coffee) a day, may cause male and female infertility

(-) In animal experiments, pregnancy results are worse if caffeine intake is high. Spontaneous abortion, congenital malformations, delayed fetal development, and residual effects of newborns

(-) Caffeine stimulates breathing. This effect is mediated by the neurotransmitter dopamine and serotonin.

The US military is very interested in the physiological role of caffeine in hydration. For the soldiers to bear the heat of Iraq, the military needs to know how to optimize hydration. Therefore, they examined the effect of medium and high doses of caffeine (3 and 6 mg / kg body weight) on hydration supplementation. This corresponds to a subject who ingested relatively small amounts of caffeine habitually - a cup of coffee 6 ounces (100 mg / day; caffeine about 1.3 mg / kg), but caffeine does not adversely affect urine 24 hours (Armstrong, In't J Sports Nutr, June 2005) On the last day, loss of urine is similar to those who do not take caffeine or high doses.

This document supports the fact that caffeine is less toxic and does not cause serious physiological side effects in adults (Rall, 1985; Stavric, 1988). The physiological effect of caffeine varies depending on whether the subject is inexperienced or ordinary users of caffeine. In subjects who did not ingest caffeine, systolic blood pressure increased by 11 mm Hg at an oral dose of 250 mg (Robertson and Curatolo, 1984). Heart rate decreased in the first hour after administration and heart rate increased beyond baseline at 2 hours thereafter. Systolic blood pressure of the average user who lacked caffeine increased significantly (4 mm Hg), but conventional users who were not deprived of caffeine did not significantly rise. Other researchers found that there was no significant change in blood pressure or heart rate even after 500 mg orally administered (Bruce et al., 1986; Myers 1988). Newcomb et al. Lack of specific research on cardiovascular effects of 500 mg or more of caffeine

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