19 September 2011


Serotonin and aggression. According to new research from the University of Cambridge, "fluctuations of serotonin levels in the brain, which often occur when someone hasn't eaten or is stressed, affects brain regions that enable people to regulate anger .... the research revealed that low brain serotonin made communications between specific brain regions of the emotional limbic system of the brain (a structure called the amygdala) and the frontal lobes weaker compared to those present under normal levels of serotonin. The findings suggest that when serotonin levels are low, it may be more difficult for the prefrontal cortex to control emotional responses to anger that are generated within the amygdala."

Stress and diet are only two of a range of factors which influence an individual's predisposition to anger and aggression. Still, the more we understand about the anatomy (structure) and physiology (function) of our bodies, the better prepared we are to make informed choices about lifestyle in general, and behavior in particular situations.

Calories. Thanks to my friend Tess for this essay on metabolism and diet. Dr. Mark Hyman starts by posing the rhetorical question, "what is a calorie? A calorie is a simple unit of energy. It is defined as the quantity of [heat] required to raise the temperature of 1 gram of water by 1 degree [celsius] at atmospheric pressure." Our bodies intake calories in food, and we burn calories through metabolism. So if one is attempting to lose weight, then one ought to be able to simply limit one's intake of calories, right?

Not necessarily. According to Dr. Hyman, "The calories you eat are absorbed at different rates, have different amounts of fiber, carbohydrates, protein, fat, and nutrients ~ all of which translate into different complex metabolic signals that control your weight .... the kinds of calories you consume have a big impact on how much fat you gain, because different kinds of food are metabolized in different ways."

The essay goes into greater detail on how this works. I found it to be very informative, especially in light of my own experiences with weight loss. One method (when I was young and naive) was simply to fast, intaking nothing but water and fruit juices. No surprise that when I stopped fasting, the weight returned. I undertook a much more successful method at age 57, when my weight reached a lifetime high of 200 lb. (compared to 155 lb. in high school). I chose a target daily intake of 1200 calories, aiming for a gradual but sustainable weight loss of 1-2 lb. per month. This method worked quite well for me. At 5 feet 9 inches, my optimal weight range according to the body-mass index (BMI ~ see the chart here ) is 131-160 lb. The closer to the lower end of one's personal range, the healthier one generally is. I'm now at 140 lb., and able to sustain that weight easily by eating well and exercising daily.

CPR. Cardio-pulmonary resuscitation (CPR) training has long called for alternating rhythmic chest compression with artificial respiration, in order to restore spontaneous blood circulation and breathing for someone who is in cardiac arrest. Everyone should receive recurrent training in both CPR and first aid, available in most communities through the Red Cross.

Fairly recently, CPR procedure was simplified to include only chest compressions, presumably to accomodate untrained rescuers. Here is a brief video demonstrating the revised technique, dubbed continuous compression CPR. I confess to a certain degree of doubt ~ far better, in my mind, to be recertified throughout one's adult life, than to let that training lapse. If you click on the link and look at the comments below the video, you'll find an important warning. "It is indispensable that continuous compression CPR be applied only if the victim shows clear signs of heart failure. In an emergency, that is not always an easy call for an uninformed person to make. Continuous compression CPR will aggravate the problem or hasten the death of a victim who is suffering from internal bleeding, from stroke, or from profuse bleeding from an external wound."

Good point. All the more reason for everyone to become informed. There is no substitute for proper training. That is part of our responsibility to ourselves, to our families, and to society.

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