19
votes
Accepted
Why do I feel shaky after only a small amount of caffeine?
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 ...
- 7,717
11
votes
Did science backtrack regarding coffee causing dehydration?
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 ...
- 15.6k
9
votes
Accepted
What effect does long-term caffeine use have on memory?
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 ...
- 1,838
9
votes
Accepted
Water vs. Coffee when hungry at work
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 ...
- 2,803
8
votes
Alternative to caffeine - same effects, different chemical
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 ...
- 2,803
8
votes
Does decaffeinated coffee inhibit iron intake as much as normal coffee does?
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, ...
- 466
7
votes
Accepted
Can coffee worsen or trigger a cough?
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 ...
- 1,836
6
votes
Why does caffeine make me sleep better?
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 ...
- 2,952
6
votes
Accepted
Does tea cause gags?
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 ...
- 2,803
6
votes
Accepted
Can caffeinated shampoo have a noticeable effect?
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 ...
- 746
5
votes
Accepted
What is the amount of caffeine in the human body over time?
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 ...
- 9,314
5
votes
Accepted
ADD medication (Dexadrine) safe to drink with low-caffiene (Mountain Dew)?
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 ...
- 565
5
votes
Why do I feel shaky after only a small amount of caffeine?
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 ...
- 4,697
5
votes
How much space should be in between taking an antidepressant and drinking coffee?
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 ...
- 2,770
5
votes
Accepted
Why does caffeine raise your blood pressure when it's a diuretic?
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 ...
- 13.2k
5
votes
Accepted
How to reduce half-life of caffeine?
TLDR summary of what I found:
diet-wise brassica vegetables, in particular broccoli seems to have this effect (but other vegetables that share P450 inhibitors in common with citrus fruits have the ...
- 5,773
4
votes
How much space should be in between taking an antidepressant and drinking coffee?
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 ...
- 2,322
4
votes
What is wrong with taking coffee and methylphenidate together?
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 ...
- 6,998
4
votes
Accepted
Should people with tachycardia avoid caffeine?
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 ...
- 15.6k
3
votes
Accepted
How does coffee affect blood sugar levels?
As a type 1 diabetic I have noticed even black coffee can have an effect on blood sugar. Coffee( the caffeine really) increases your blood epinephrine (adrenaline) levels. Adrenaline has the same ...
- 66
3
votes
Can drinking alcohol release stored caffeine?
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 ...
- 1,970
3
votes
Is Moderated Caffeine Good? (if so how much and how often)
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 ...
- 151
3
votes
Accepted
Does caffeine have any distinct biological effects to adrenaline?
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 ...
- 15.6k
2
votes
Is there a (quasi-)healthy way of resisting sleep?
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 ...
- 749
2
votes
Does caffeine reduce mass gaining by accelerating metabolism?
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 ...
- 1,083
2
votes
What is the amount of caffeine in the human body over time?
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
...
- 151
2
votes
Accepted
Risks of Caffeine Powder
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 ...
- 1,083
Only top scored, non community-wiki answers of a minimum length are eligible