I loveee drinking coffee. So you may find more and more information on coffee from time to time in my blog (^-^)
Caffeine can be found in tea, coffee beans, guarana berries and cocoa nuts. It stimulates our central nervous system. The effects of caffeine differ on each and every one of us. Caffeine in short term could cause contraction of muscles, which may lead to:
· Twitching
· Increase heart rate
· Blood flow to stomach slows down
· Contriction of blood vessels on our skin
· More sugar is released from liver into our bloodstream
· Breathing tubes open up
Coffee can cause harder to sleep for some people. For some of us, it can also cause us to experience deep sleep for shorter periods, and shorter dream periods. So when we wake up, we would feel less rested.
Caffeine reaches maximum concentration in the body after 1-½ hours. After 3 to 7 hours, the caffeine in our body is metabolized and then expelled from our body.
Caffeine is metabolised by the liver, and passes into the bloodstream, crossing the blood/brain barrier into the brain. There it binds with receptors including dopamine receptors (which is why it makes you feel good) and adenosine receptors. Adenosine when bonded to its receptors slows down nerve cells, causing drowsiness. Caffeine also binds to adenosine receptors but doesn't slow down nerve cells. Since there is less adenosine binding, the nerve cells speed up, leading to feelings of restlessness.
Excessive caffeine intake, which is more than 4 or 5 cups of strong tea or coffee per day, can cause tremors, a fast heart rate, increased urination, nervousness, anxiety, stomach upsets and insomnia. In rare cases, caffeine can cause death relevant to heart condition.
Caffeine has a greater affect on children and the elderly. It can cause unborn babies to experience restlessness and withdrawal symptoms at birth, and produce hyperactivity and anxiety in kids.
The rate at which caffeine is metabolised by the body depends on the health of the liver. Women in general have more enzymes in the liver and metabolise drugs like caffeine faster than men.
The same class of enzymes metabolise caffeine and the hormones of pregnancy. It takes longer to get rid of the caffeine when these hormones are elevated in the body, that is, if you're pregnant or on the oral contraceptive pill. Low to moderate consumption of caffeine (one to two cups per day) has no effect on pregnant women’s birth weight or risk of miscarriage.
For some of you who are trying to make baby (^-^), please note that, caffeine has been shown to reduce fertility by damaging sperm in men. On women, it affects whether or not the fertilised egg (embryo) successfully implants in the uterus. Caffeine is a stressor; it stimulates the heart and brain, however also stimulates the release of a hormone that negatively interacts with the hormones that control fertility. As little as one cup of strong coffee a day can affect the chances of successful conception.
And for breastfeeding mom, do note down that caffeine can enter breast milk and significant amounts can cause wakefulness and agitation to the baby. Again, one cup per day seems to be the recommended upper level of intake.
However, there are some benefits in caffeine consumption. Caffeine is an antioxidant. Antioxidants are thought to help prevent heart disease and some cancers. Furthermore, coffee also contains flavonoids, which are also antioxidants. I read somewhere before that coffee is as strong as 6x antioxidants.
Caffeine increases alertness and is thought to improve concentration. It has also been used to help premature babies experiencing difficulties breathing. Minute amounts of caffeine given intravenously once a day can stimulate a newborn baby's brain to tell the lungs to inflate.
All in all, we can still drink coffee, or may be green tea or chocolate, as long as in moderate amount. So it is enough to benefit our body, and yet still far to experience the negative effects.
