| Author |
Message |
    
Miisa
flint knapper
Username: Miisa
Post Number: 776
Registered: 5-2003
| | Posted on Thursday, June 29, 2006 - 8:10 pm: |     |
Does adrenaline heighten or lower the appetite, or is it perhaps neutral? |
Rhi
hunter
Username: Rhi
Post Number: 448
Registered: 5-2003
| | Posted on Friday, June 30, 2006 - 2:33 am: | |
No idea, but from personal experience (I have an overactive adrenal gland, which helps spur on panic attacks), when I'm having a period of panic attacks, I can't eat. Even if I force it down, it comes back.
When I've been really relaxed (adrenal gland is behaving itself), I'm always hungry. So, from personal experience, I'd guess that if adrenaline has any effect, it lowers the appetite, and perhaps when the extra leaves the system, the appetite returns, maybe heightened for a period.
I'm really interested in the answer to this question.
Mostly Harmless
A Knock on the Duir "If ye don't be belaving innything what fun are ye going to get out av life?" Judy Plum, LM Montgomery |
Cavebear
cave painter
Username: Cavebear
Post Number: 2719
Registered: 9-2003
| | Posted on Friday, June 30, 2006 - 2:52 am: | |
Well, adrenaline increases some bodily responses (increased heartbeat and breathing, for example) and supresses other bodily functions. It may seem a wash, but any energy used has to come from somewhere. So if the body uses energy, it must restore it. Ultimately, adrenaline must increase appetite.
Machiavelli was pretty devious. For a guy... |
Miisa
flint knapper
Username: Miisa
Post Number: 777
Registered: 5-2003
| | Posted on Friday, June 30, 2006 - 8:38 am: | |
Interesting. I have always assumed what Cavebear explains, that the appetite must increase after an outburst of adrenaline, but lately I have been getting small adrenaline "fixes" 3-5 times a day and constantly just a little "buzzed", and have been experiencing Rhi's description. I eat next to nothing (a few bites is fine, after that the food takes on first the taste and then also the texture of finely aged cardboard) and sleep very little, too, yet I am not as tired as I would expect (at least not while remaining active), nor do I have the headaches I would associate with eating too little. |
Annie
storyteller
Username: Annie
Post Number: 1841
Registered: 5-2003
| | Posted on Friday, June 30, 2006 - 11:43 am: | |
I would have assumed Cavebear had it right too. 
OK, so while my knowledge of biology approaches zero (probably from the negative side), I'll venture a guess. 
AFAIK, in nature adrenaline is released into the system as a response to immediate danger; at such times, the organism must be alert and focused, to function at its absolute best. It stands to reason that being distracted by hunger and its symptoms would hamper its performance, and therefore adrenaline might have a side effect as an appetite-suppressant.
However, I wouldn't think that a constant or oft-recurring adrenaline high would be a healthy state, first because, as Cavebear said, the energy used up does need to be replenished eventually, and second, a speeded-up metabolism means increased wear on the organs, and ultimately a correspondingly lowered life expectancy.
Chess is the purest form of debate, unadulterated by a topic. |
Sweetsunray
storyteller
Username: Sweetsunray
Post Number: 1030
Registered: 9-2003
| | Posted on Friday, June 30, 2006 - 3:58 pm: | |
Annie: and second, a speeded-up metabolism means increased wear on the organs, and ultimately a correspondingly lowered life expectancy
Wrong... A high metabolism rate increases life expectancy... otherwise being a couch potatoe would be the way to live a long and healthy life. But the medical advice is to train and exercise, and thus increasing your metabolism rate, all in order to prolong life expectancy.
lifespan
exercise and lifespan
But I agree with the observation that at times when our adrenaline levels go up (such as riksylife situations), these are not the times to be eating food. When we eat, and have our stomach work on the food the first hours, we need lots of blood there to have these muscles work. As a consequence it's not good for us to require our body to do other stuff during digesting time... Both physical exercise and high mental performance would interfere with the digesting, as then more blood needs to go to the brains and muscles. That's why people are advized not to swim the first two hours after having a meal. Swimming not only involves muscle exercise, it also involves blood exercise for the skin to keep your inner temperature at the appropriate leve. Meanwhile neither your brain or muscles are in the capacity to peak function, and thus the risk of drowning or drowning because of hypothermia will increase. And that's why you feel sleepy after say lunch, and your body gets into a siesta mode. If you take a nap, more blood can be used to help you digest the food.
Since situations your body pumps you full of adrenaline for, normally are situations that require a quick mind and high physical exercise and reflexes, as much blood that can be possibly spared needs to go to the brains and muscles... By bringing down apetite or even make you nauseous at the thought of food, you're less likely to eat, less likely in the process of digesting, less likely to feel drowsy (which would absolutely interefere with the required alertness) and using less blood for the digestion process.
So adrenaline -> makes you less hungry.
Of course, once the adrenaline has left your system fully, and you're fully relaxed again; you do need to replenish, and then might feel very hungry to make up for the exercise you did. But it will take some time before you will, because only time can tell that you're in a safe situation again to go take a nap for two hours. Miisa, since you have so many adrenaline kicks on one day, your body remains in a heightened alertness state, and never relaxes enough to allow you to eat and get drowsy because of digestion.
Everyone has a motive for giving arguments. But only the arguments given matter. |
Annie
storyteller
Username: Annie
Post Number: 1844
Registered: 5-2003
| | Posted on Friday, June 30, 2006 - 10:40 pm: | |
Err, SSR, the links you gave don't seem to support your declaration that what I said was wrong. Animals with faster metabolisms may get more work out of their tissues, but chronologically they still live much shorter lives.
Also, there is a big difference between the normal physical activity level, and corresponding metabolic rate, that our bodies evolved for, and the "couch potato" activity level - as big one way, as the difference between that same normal level and an adrenaline-high is, going the other way. Neither extreme is healthy, but the problem with being a "couch potato" is more in the health hazards of being overweight and unfit, rather than a direct result of the slower metabolism.
Excellent explanation on the correlation between adrenaline, blood flow, and digestion, though. 
Chess is the purest form of debate, unadulterated by a topic. |
Sweetsunray
storyteller
Username: Sweetsunray
Post Number: 1031
Registered: 9-2003
| | Posted on Saturday, July 01, 2006 - 12:27 am: | |
Though mice may have shorter life span than elephants regarding sun years, they have a logner life span regarding heart beats... they live more heartbeats than elephants do.
The second link explains how a higher metabolism, and thus exercise, and thus increasing the heartbeats is healthy, and increases your life expectancy
quote:A high rate of metabolism is the key to the answer. Remember, the striking outcome of John Speakman’s study was on the tissue level. Tissue in small animals, who have high metabolic rates, lives longer than tissue in larger animals. Thus, mice and other small animals live longer lives in terms of heartbeats than larger animals.
"So, exercise not only increases our numbers of heartbeats, it also increases our metabolic rate," Speakman emails, "and there is good evidence that it [exercise] is linked to decreases in all causes of mortality."
Everyone has a motive for giving arguments. But only the arguments given matter. |
Annie
storyteller
Username: Annie
Post Number: 1845
Registered: 5-2003
| | Posted on Saturday, July 01, 2006 - 11:49 am: | |
And since when is life expectancy measured in heartbeats?
I have read those articles (they are at the same site and the second is a sequel to the first, btw), and they strike me as simply a sensationalist and smart-alecky "oooh-look-what-an-original-take-we-have-on-things " sort.
When you ask about the life expectancy of an animal, you expect to get an answer in time units. Examples:
Q: What is the life expectancy of a mosquito?
A: 3-4 weeks.
Q: What is the life expectancy of a mouse?
A: 2-3 years.
Q: What is the life expectancy of a hippopotamus?
A: 30 years.
These are time units. Your referenced articles simply replace the sensible term "time units" with the term "sun years", which is bafflingly unusual and even carries mystical overtones, in the rather transparent hope that the odd term will make the decidedly unorthodox alternative measure they propose (heartbeats) more acceptable in contrast. A pure semantical shenanigan. 
As for the second article, the question it is purported to answer is a specific and good one:
quote:Q: I read with interest your response as to why larger animals live longer than small animals (slower metabolism and having a limited number of breaths and heartbeats). But we are all encouraged to exercise in order to live longer. Exercise uses up the breaths and heartbeats faster than someone at rest. So, any idea at which point they cancel each other out?
but the "answer" which you have quoted, is just more vague handwaving of the same sort. Ya, exercise is linked to decreases in all causes of mortality, and is also linked to metabolic rate. Duh. But the link between raising metabolic rate, and decreasing various causes of mortality, is indirect at best.
Chess is the purest form of debate, unadulterated by a topic. |
Catfriend
gatherer
Username: Catfriend
Post Number: 145
Registered: 12-2005
| | Posted on Saturday, July 01, 2006 - 2:54 pm: | |
I'm no more knowledgeable in biology issues than Annie claims to be, but FWIW - "the word of the net":
http://tjsamson.client.web-health.com/web-health/t opics/GeneralHealth/generalhealthsub/generalhealth /lifestyle/Death/life_expectancy.html
"Biologists have noticed a correlation between basal metabolism and life expectancy: the faster the basal metabolic rate, the shorter the lifespan."
According to http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd= Retrieve&db=PubMed&list_uids=3738973&dopt=Abstract, free radicals (their amount increases with increased metabolism), "may be supposed to underly the process of aging."
From http://www.hhmi.org/cgi-bin/askascientist/highligh t.pl?kw=&file=answers%2Fmolecular%2Fans_020.html:
"The "free radical theory," originally proposed by Denham Harman in 1956, remains the most viable contender to explain the basis of aging in a wide range of species, including humans. The theory suggests that aging can be attributed to deleterious effects of free radicals, or reactive oxygen species (ROS), on various cell components. A principal site for ROS generation is the mitochondrion, where free radicals are generated in the process of respiration. That is why we can say that oxygen metabolism is connected with aging.
Higher metabolic rate is generally correlated with faster aging, while caloric restriction is known to extend life span. It is now thought that this phenomenon can also be linked to the rate of mitochondrial metabolism and, ultimately, the rate of production of cell-damaging ROS. An additional link between the level of ROS and the rate of aging is suggested by observations that the artificial treatment of cells with chemicals that produce ROS can mimic many of the cellular changes seen with aging.
Two more lines of evidence provide support for the free radical theory. The first comes from transgenic animals that are engineered to overexpress ROS-scavenging enzymes. It turns out that such animals have a longer life span, which correlates with the reduction of ROS levels in their tissues provided by the ROS scavengers. The second line of evidence shows that mutations that extend the life span of model laboratory organisms (such as fruit flies, worms, and mice) at the same time make these animals more resistant to ROS-generating chemicals (for example, paraquat). "
Yet, to be fair, we have also the recent http://web.mit.edu/newsoffice/2002/guarente.html, claiming
"CAMBRIDGE, Mass. -- In results that counter the idea that oxygen free radicals cause aging, an MIT researcher reports in the July 18 issue of Nature that calorie restriction prolongs life because it increases respiration, not because it decreases oxygen free radicals.
MIT biologist Leonard Guarente believes "the conventional wisdom on oxygen radicals is dead wrong. Our results (in yeast) are contrary to the frequent suggestion that calorie restriction functions by slowing metabolism and thereby slowing the generation of free radicals."
Guarente, who is working on a book on aging to be published this fall, discovered in 2000 that calorie restriction activates the silenced information regulator (SIR2) gene, which has the apparent ability to slow aging. This gene makes a protein called Sir2, which Guarente has shown is integrally tied to extending life span in yeast and in the roundworm. Humans carry a similar gene.
Rather than a slower metabolism leading to a slower rate of respiration, it turns out that respiration in yeast cells under calorie restriction goes up, not down. "The increase in anti-oxidant enzymes that is reported to occur during calorie restriction in animals may be a result of an increase in respiration rather than a cause of the observed longevity," Guarente said. "
One Ring to rule them all
One Ring to find them
One Ring to bring them all
And in the Darkness bind them! |
Cavebear
cave painter
Username: Cavebear
Post Number: 2724
Registered: 9-2003
| | Posted on Saturday, July 01, 2006 - 8:26 pm: | |
I'm avoiding the question of metabolism and "lifespan", of which I know little other than having read once that every mammal has about a billion heartbeats in it and that we are an exception because of medical technology.
However, when I said that adrenaline causes increased hunger, I did not mean immediately. Indeed, in the short term, it causes reduced hunger. The purpose of adrenaline seems to be to prepare the body for sudden and extreme muscular activity "fight or flight". Routine bodily functions such as eating suppressed.
I have no experience ingesting (injecting?) adrenaline such as Miisa described (didn't even know you could do that). But anything that causes the body to increase metabolism (increased heartbeat, breathing, musculature movement, etc) uses energy and must be replaced. You will not be hungrier immediately, but you be hungrier eventually.
It occurs to me that people with excess stored energy sources (body fat) may react to adrenaline in different ways (or at least on a different time scale). And, lest that seem insulting in some way to anyone, I will easily admit to about 15 pounds of "excess stored energy sources" myself (according to standard medical charts). I don't mind it; it never hurts to be prepared for when the crops fail.
Machiavelli was pretty devious. For a guy... |
Annie
storyteller
Username: Annie
Post Number: 1846
Registered: 5-2003
| | Posted on Saturday, July 01, 2006 - 9:20 pm: | |
Nice collection of sources, Catfriend! That's some fascinating material - I'll have to go through it carefully... thanks.
Cavebear: It occurs to me that people with excess stored energy sources (body fat) may react to adrenaline in different ways (or at least on a different time scale). And, lest that seem insulting in some way to anyone, I will easily admit to about 15 pounds of "excess stored energy sources" myself (according to standard medical charts). I don't mind it; it never hurts to be prepared for when the crops fail.
My lawyer said not to admit anything...  anyhoo, I think there wouldn't be a difference, exactly because your body agrees with your philosophy about the failing crops, and tends to request regular calory intake (i.e., hunger), resorting to using up its reserves only in emergency, when nothing has been incoming for a while. I don't remember where I picked that up... I did read it somewhere sometime, but it stands to reason too, otherwise many of us would never be hungry... uh-oh, I didn't admit anything, did I? 
Chess is the purest form of debate, unadulterated by a topic. |
Miisa
flint knapper
Username: Miisa
Post Number: 778
Registered: 5-2003
| | Posted on Saturday, July 01, 2006 - 9:57 pm: | |
CB:I have no experience ingesting (injecting?) adrenaline such as Miisa described (didn't even know you could do that).
I'm not, I am just doing something that causes my levels to rise naturally (very moderately, mind) on a regular basis, they are especially good with endorphins. Exercise junkies do it all the time.
I was just wondering whether it might be the adrenaline/endorphins that have caused me to stop eating or if it might have been the ulcer (?) I suspect I developed a week or so ago.
Creative-aggressive |
Rhi
hunter
Username: Rhi
Post Number: 449
Registered: 5-2003
| | Posted on Sunday, July 02, 2006 - 1:00 am: | |
CB: "It occurs to me that people with excess stored energy sources (body fat) may react to adrenaline in different ways (or at least on a different time scale). And, lest that seem insulting in some way to anyone, I will easily admit to about 15 pounds of "excess stored energy sources" myself (according to standard medical charts). I don't mind it; it never hurts to be prepared for when the crops fail."
NOt sure if it has any effect or not. From experience, (carrying extra weight), when my adrenaline started to go hyperactive, and my appetite went down, I lost about 15 pounds (I couldn't eat and keep it down for about 10 days), then, once my levels stared leveling out, I gained the weight back. I don't think I ate more than normal or was more hungry, but it came back to my then normal weight eventually.
Mostly Harmless
A Knock on the Duir "If ye don't be belaving innything what fun are ye going to get out av life?" Judy Plum, LM Montgomery |
joslin (Unregistered Guest)
visitor
| | Posted on Wednesday, May 21, 2008 - 6:11 pm: | |
does anyone else find that adrenaline rushes cause excessive hunger 1 or 2 days later? |
Scott
storyteller
Username: Scott
Post Number: 2440
Registered: 5-2003
| | Posted on Tuesday, July 01, 2008 - 6:33 pm: | |
Adrenaline suppresses hunger, but what you might be experiencing is after the suppressed hunger, with not more adrenaline that your body reverts to its normal appetite which manifests itself as excessive hunger, when in actual fact it is just normal hunger.
Scott
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