Drinks 8 Glasses of Water a Day? Myth Busted?

Almost everybody has heard this advice... "Drink at least eight glasses of water a day." Really? I decided that there must be some scientific basis for this recommendation, right? According to a review (2002) by Dartmouth physiologist and medical doctor Heinz Valtin, the advice to consume 8 glasses of water per day (approximately 1.9 liters!) has no apparent basis in the scientific literature. Here is the link to his article in the American Journal of Physiology where he discusses the origins of this advice and whether it is necessary to consume large amounts of water each day.

My interpretation of Dr. Valtin's review is that the average person does not need to gulp down water incessantly all day long. It seems most people end up drinking enough fluid during the day from various beverages including coffee, carbonated drinks and of course water (about 1.5 liters from all sources). So chances are you are already drinking enough water everyday, so perhaps you can stop stressing about it. Of course, if if if you exercise strenuously, work outside, or live in a dry climate then you probably have an increased need for fluid intake.

"... it is hard to imagine that evolutionary development left us with a chronic water deficit that has to be compensated by forcing fluid intake..."

So who or what is behind the popular belief that we are all walking around chronically dehydrated and that we are all in dire need of some cool, clean, and refreshing water? Maybe the bottled water industry has something to do with it? The industry spent $168 million in advertising and made over $11 billion in sales in the United States for 2006-2007 (source). But hey... drink water rather than soda or coffee (its free from the faucet and no calories) but don't panic if you forget the precious water bottle on your way to school. Chances are you won't shrivel up like a prune or ruin your kidneys.




~~~BIO26~~~

She's Hot + He's Not = Happiness in Marriage

You have seen the celebrity couples and probably know some married folks where the spouses seem equally attractive while sometimes one spouse is clearly better looking than the other... so does this have anything to do with happiness, satisfaction, and success of the marriage? A recent study in the Journal of Family Psychology just might have the answer. The research study is titled "Beyond Initial Attraction: Physical Attractiveness in Newlywed Marriage" and was performed by psychologists from UCLA and the University of Tennessee. Here is an excerpt from the study (PubMED link to article):

Physical appearance plays a crucial role in shaping new relationships, but does it continue to affect established relationships, such as marriage? In the current study, the authors examined how observer ratings of each spouse's facial attractiveness and the difference between those ratings were associated with (a) observations of social support behavior and (b) reports of marital satisfaction. The relative difference between partners' levels of attractiveness appeared to be most important in predicting marital behavior, such that both spouses behaved more positively in relationships in which wives were more attractive than their husbands, but they behaved more negatively in relationships in which husbands were more attractive than their wives.

You might assume from this that, in terms of longterm relationships, physical attractiveness is less important to women while more important to men. One psychologist suggested that when women who are beautiful go out with men who aren't so hot, the men try harder so it makes for a better marriage for both spouses. But remember, this study is not evaluating the importance of physical attraction in dating or initial relationships but rather how relative attractiveness of spouses influences satisfaction and behavior of the couple longterm. This story was reported in the StateHornet as well as many other news sources in the past weeks, including the New York Daily News. Follow the links for some interesting reading.

So, does this mean that women will run out and start dating and marrying men who are less attractive than them? I sure hope so! Haha... but probably not... it turns out scientific research also shows that we are really bad at predicting what will make us happy in life. Psychologists have a term for our brain's inability to accurately predict future happiness... it is called affective forecasting error... but that is a topic for another day.





~~BIO26~~

Disturbing trend: Life Expectancy Decreasing for Some in US...

Average life expectancy has steadily increased in the United States over the years. However, there was a steady increase in mortality inequality across portions of the US during the 1980's and 1990's, resulting from stagnation or increase in mortality among the worst-off segment of the population. Female mortality increased in a large number of counties, primarily because of chronic diseases related to smoking, overweight and obesity, and high blood pressure. Here is a link to the recently published research findings, PLoS Medicine.

Analysis of the study from the Public Library of Science:

The findings suggest that beginning in the early 1980s and continuing through 1999 those who were already disadvantaged did not benefit from the gains in life expectancy experienced by the advantaged, and some became even worse off. The study emphasizes how important it is to monitor health inequalities between different groups, in order to ensure that everyone—and not just the well-off—can experience gains in life expectancy. Although the “reversal of fortune” that the researchers found applied to only a minority of the population, the authors argue that their study results are troubling because an oft-stated aim of the US health system is the improvement of the health of “all people, and especially those at greater risk of health disparities”

~~BIO26~~

American Heart Association joins the club: new CPR

Continuous chest compression CPR or hands only CPR is now recommended by the American Heart Association for adults that collapse suddenly, presumably due to cardiac arrest. You can read more about this new, simplified version of CPR in the previous blog post on February 9th and also at this "hand only" CPR website. The following are new guidelines from the the American Heart Association Emergency Cardiovascular Care Committee (link to AHA source): [source link]

When an adult suddenly collapses, trained or untrained
bystanders should—at a minimum—activate their community
emergency medical response system (eg, call 911) and
provide high-quality chest compressions by pushing hard and
fast in the center of the chest, minimizing interruptions.

● If a bystander is not trained in CPR, then the bystander
should provide hands-only CPR. The rescuer
should continue hands-only CPR until an automated external
defibrillator arrives and is ready for use or EMS
providers take over care of the victim.

● If a bystander was previously trained in CPR and is
confident in his or her ability to provide rescue breaths
with minimal interruptions in chest compressions, then the
bystander should provide either conventional CPR using a
30:2 compression-to-ventilation ratio or handsonly
CPR. The rescuer should continue CPR until an automated
external defibrillator arrives and is ready for use or EMS
providers take over care of the victim.

● If the bystander was previously trained in CPR but is not
confident in his or her ability to provide conventional CPR
including high-quality chest compressions (ie, compressions
of adequate rate and depth with minimal interruptions)
with rescue breaths, then the bystander should give
hands-only CPR. The rescuer should continue
hands-only CPR until an automated external defibrillator
arrives and is ready for use or EMS providers take over the
care of the victim.

~~BIO26~~

Extreme cancer surgery involves temporarily removing digestive organs

Wow, the case of an extreme cancer surgery is currently being reported on the news. The operation removed (only temporarily) several organs and then the organs had to be sutured back in place. The removal was needed to get access to the cancer in the posterior wall of the patient's abdominal cavity. The article stated that the operation was like taking the engine out of a car in order to repair the car while it is still running.

It took seven surgeons more than 15 hours, in which they removed her stomach, pancreas, spleen, liver and large and small intestines, while keeping Zepp (the patient) alive. Once they cut out the tumor, which was wrapped around a major artery, they painstakingly put all the organs back in her body. - ABC NEWS Online

The removal of the tumor was complicated by its location in the abdomen. Reportedly, the small tumor was wrapped around the aorta and the base of the celiac trunk and superior mesenteric artery. Some portions of her blood vessels had to be replaced with artificial vascular grafts made of Gore-Tex (BIO 26 students saw these in lab).

The surgery took advantage of techniques used in organ transplant operations... including cooling and preserving of the patient's digestive organs after removal from the body. The patient was diagnosed with leiomyosarcoma, a somewhat rare form of cancer of the intestines. It reportedly arises from cells in or around the muscularis mucosa. Check out eMedicine for more information on this form of caner (link to eMedicine).



~~BIO26~~

Love them or hate them... Peeps are here

March brings us two great things... endless hours of college basketball and the endless sugary pleasure of the Peep. I am not sure the relevance of Peeps to physiology or anatomy since they don't have much nutritional value,... we certainly can't measure their forced vital capacity or dissect them to study their fluffy marshmallow interior. Well, perhaps we can use them during a glucose tolerance test to increase blood glucose levels.

One research group has used the Peep as the subject of intense scientific investigation. These scientists studied the health risks of cigarette and alcohol use in Peeps. They concluded:

"The synergistic effect of smoking and alcohol in Peeps produces a rapidly exothermic oxidation reaction, leading to a chemical and morphological divergence from the wild-type Peep phenotypes. Assistant lab members described these divergent Peeps as "less sweet," "crunchier," and "gross" when compared to the Peeps which used either alcohol or tobacco, but not both. For these reasons, it is our strong recommendation to JustBorn Corporation that they supervise young Peeps and educate them of the risks associated with smoking and alcohol."

For further reading on the scientific research on Peeps follow the link courtesy of Emory University scientists and researchers. Peep Research




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My Pink Spongy Lungs...

The lungs are certainly one of the coolest organs to look at in lab class due to their light, fluffy feeling and their ability to expand to large volumes and quickly recoil... amazing! The above image shows a normal lung before and after inflation. Part of the ability of the lungs to expand and recoil is due to the extracellular matrix of the lung tissue which contains collagen and lots of elastin protein fibers. This gives the lungs their ability to recoil after inhalation so that air is exhaled properly. The videos below show this in action...





Smoking is a health hazard for many reasons such as heart disease and cancer, but smoking also can damage the physical structure of the lung. Cigarette smoking leads to neutrophil activation and retention in the lung tissues. Cigarette smoking induces macrophages to release neutrophil chemotactic factors and elastases, thus unleashing tissue destruction. A number of neutrophil-derived and macrophage-derived enzymes known as proteinases and elastases (ie, proteolytic enzymes) can destroy various components of the extracellular matrix of the lung (e.g., elastin fibers) and cause emphysema (see eMedicine). The tissue integrity of the tiniest airways (like the alveoli and respiratory bronchioles) is destroyed over time and normal elasticity is lost. There is also destruction of the aveolar capillaries which impairs gas exchange in the lung. All of this reduces the ability of the lungs to function and this is especially noticeable when patients with emphysema are asked to expire after maximal inhalation. It takes them longer to expire air out of their lungs since exhalation requires the inherent elasticity of the lung tissues, which they have lost with emphysema.



~~BIO26~~