19
Caffeine metabolism has to do with your genetic makeup. The slower you metabolize caffeine, the more effect it will have on you. The cause for the differences that people have in how fast they metabolize caffeine has to depend on the CYP1A2 gene. Variants of this gene can cause you to metabolize faster or slower. The C allele variant in the AHR gene, which ...
10
Why it has been long assumed that caffeine or coffee is dehydrating?
Because caffeine is a mild diuretic - it stimulates water excretion through the kidneys. But the amount of water you consume with caffeinated drinks is usually greater than the amount of water you lose in urine due to caffeine diuretic effect, so there is no net water loss and hence no ...
9
Short answer:
A pack of raisins.
Yes, I've read your question through and through. Please, bear with me for a while, to see the longer answer:
The problem with concentration when you haven't eaten arises primarily because of the lack of nutrients, i.e. glucose.
Glucose is virtually the sole fuel for the human brain, except during prolonged starvation. The ...
8
There is a substance similar to caffeine - theobromine, found in cocoa. They are chemically similar, and have some similar effects*:
the formula above shows theobromine,
and this is caffeine.
Of course, there is the concern if you react like you described to one xanthine derivative (caffeine), would you react in a similar way to another compound from this ...
8
There are actually quite a lot of studies pointing in all directions when it comes to memory and caffeine use. I wouldn't call it a closed case by any standard, although many sites hawk caffeine as a great improver of memory, especially long-term memory.
Some studies showing no effects of long-term caffeine use on memory:
Hameleers et al. (2000): A large ...
7
Does coffee inhibit the absorption of iron? The answer appears to be yes (see links and references below). So does tea. Note that this does not have to do with caffeine, but rather polyphenols, phytates found in them. So, my answer would be that both regular coffee and decaf coffee inhibit iron, but I don't know whether one does so more than the other. Also, ...
7
The quick answer is unfortunately it depends.
If we break this question down, there are three ways coffee would likely be able to effect a cough:
The coffee directly interacts with virus (and it is most likely a virus) causing the cough
Coffee could directly effect your immune system in such a way that it changed your body's ability to respond to the ...
6
Caffeine Absorption Caffeine Capsules - 200mg - 84-120 minutes
So maybe you took the caffeine, were already tired so you napped(2 hours or 120 minutes) just as it was kicking in full blown and then woke up a little later with the effects already in action, but not sleeping the full amount.
Since the capsules take longer to kick in than liquids and ...
6
I haven't found any studies that would directly link retching and the consumption of tea. However, this would be a rather narrow research, so the lack of it is no surprise. Your doctor told you that your acidity problems may be caused by tea and that this might be causing your gags, and they are correct.
It has been proven that consumption of tea is ...
6
There is a study described at nih.gov about the rate of absorption of caffeine through the skin and how hair follicles contribute to it ("significantly", is apparently the answer to that). Another study compared how three different substances, including caffeine traveled through different thicknesses of skin in humans and animals
The first-referenced ...
5
Caffeine is readily absorbed, with up to 99% absorbed within 45 minutes of ingestion.[1]
The mean half-life in healthy individuals is 5 hours, although this varies widely between individuals, ranging from 1.5 to 9.5 hours. For our purposes, we'll use the mean of 5 hours.[1]
Knowing the above plus how much caffeine you've ingested will allow you to plot ...
5
Micromedex does not list any precautions or patient educations notes for Dexedrine and caffeine. However both substances can have an effect on heart rate and blood pressure. Large amounts of caffeine like energy drinks or espresso would be ill advised, but I wouldn't think the small amount in a pop would have significant effects especially if you're decently ...
5
All caffeinated beverages like coffee (even decaffeinated) and soft drinks give short bursts of energy, temporarily raise blood pressure, and reduces blood flow to inactive limbs.
Soon after you drink coffee (containing caffeine), it’s absorbed through the small intestine and dissolved into the bloodstream and it’s able to penetrate the blood-brain barrier ...
5
what is the medically advised time between taking an antidepressant and coffee?
There is no such time, and there cannot be. All we know is that there are negative consequences when you take them together. We know that there are must be spacing schedules when the consequences must be milder than with other schedules. But we have neither the data nor the ...
5
Caffeine increased plasma renin activity by 57 per cent, plasma norepinephrine by 75 per cent and plasma epinephrine by 207 per cent. Urinary normetanephrine and metanephrine were increased 52 per cent and 100 per cent respectively. Mean blood pressure rose 14/10 mm Hg one hour after caffeine ingestion. There was a slight fall and then a rise in heart rate. ...
4
Well it depends on what antidepressant you are taking.
Caffeine works as a substrate and as an inhibitor for an enzyme called CYP1A2 (1). As so, metabolism of all other drugs which are processed by CYP1A2 enzyme are possibly influenced by administration of caffeine.
Following antidepressants are processed by CYP1A2 (2):
amitriptyline
clomi- and ...
4
As far as I can see, your source for saying these two shouldn't be combined is a user on Reddit. That is not a reliable medical source. The package inserts of Ritalin and Concerta don't mention coffee consumption. This is interesting because
coffee being such a ubiquitous drug, you'd think if the combination was dangerous or discouraged, there would be ...
4
A regular caffeine consumer will likely develop a partial or complete tolerance to many caffeine effects and side effects, including increased heart rate. Tolerance develops within few days of regular caffeine consumption and disappears within few days of caffeine discontinuation.
Tolerance to the Humoral and Hemodynamic Effects of Caffeine in Man (PubMed ...
3
Caffeine is not stored in the body.
For a normal person, peak concentration of caffeine in the bloodstream is reached between 30 minutes and 2 hours after consuming it. It's then metabolized with a half-life of 3 to 7 hours. In the situation you describe, caffeine levels are probably no more than 25% of their peak.
Various conditions and medications can ...
3
If you take coffee daily, you no longer get a boost from it after about a week, but rather, you're just staving off the harsh withdrawal symptoms, not to mention over time it will physically change your brain to have more adenosine receptors i.e., "sleepiness receptors". (Ramkumar V et al, J Clin Invest 82:242-247) in a process known as upregulation
"A 1995 ...
3
According to a case report about a 24-year old woman (PubMed Central), in agoraphobia, during a panic attack, the sympathetic nervous system is activated, which results in adrenaline release, which causes symptoms, such as:
...pounding heart, shortness of breath nervousness, dizziness, losing
control on himself for few minutes.
So, from symptoms ...
2
The answer is "really badly." There are several drugs to treat ADHD that students are taking to improve focus and study all-nighters before exams. But, this is a really unhealthy use of those medications. You most probably will eventually crash (as you would say) because you have to. This is your body's way of recovering from the damage you are imparting ...
2
Answer: No
Summary
Metabolic effects of caffeine may vary depending on whether one is 'naive' to caffeine (infrequent user) or 'accustomed' to caffeine (daily user). Metabolic effects may also vary due to genetics, specifically a polymorphism on the CYP1A1/2 enzyme (1)
One review notes that, after looking at the differences in metabolism between humans ...
2
This study correlated blood pressure and caffeine, and it showed that the body regulated after 4 days of consumption, therefore if you goal is to measure blood pressure, keep in mind tolerance
Acute caffeine in subjects who do not normally ingest methylxanthines
leads to increases in blood pressure, heart rate, plasma epinephrine,
plasma ...
2
Caffeine comes from coffee beans, but it can also be synthesized in a laboratory.
Caffeine has the same structure whether it’s in Coffee, Energy Drinks, Tea or pills/powder.
Caffeine dosages should be tailored to individuals. If you are new to caffeine supplements then the usual recommended start is with a 100mg dose (see warning below). Typically, 200mg of ...
2
There are some conflicting results concerning the effect of caffeine on nausea.
One study 1 reported that caffeine withdrawal is associated with nausea and vomiting which might suggest that caffeine might reduce nausea.
However, two years ago, a study 2 was conducted in postoperative care to reduce nausea and vomiting after general anesthesia by ...
2
A paper in Psychopharmacology reviews studies of caffeine withdrawal symptoms and concludes that these symptoms "meet the bar" for being clinically proven withdrawal symptoms:
headache, fatigue, decreased energy/activeness, decreased alertness, drowsiness, decreased contentedness, depressed mood, difficulty concentrating, irritability, and foggy/not ...
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