Wednesday, June 22, 2005

An Adventure called Yoga

Reasonably fit and in good health, there was no particular reason for us (my wife and I) to join yoga classes.

For me, it was largely a curiosity about this ancient system of exercise that involves slow stretching, some body postures and deep breathing. Not much of exercise, I thought.

We have spent the last few weeks with a group that practices yoga every morning for one hour--outdoors, in an area that is part of a golf course, all of which adds to the enjoyment.

It started out as a flirtation, but the magic of yoga has had me fascinated. It has been a tremendous learning experience so far and I intend to blog about it here, not as an evangelist, but rather as a student.

Stay tuned!

Sunday, June 19, 2005

What triggers hunger?

Dave Munger in his blog Cognitive Daily reports research that memory of what we've eaten actually accounts for a significant portion of our hunger:

Rather than being solely a physical sensation, being "full" is largely a matter of recalling that we've eaten a meal appropriate for the occasion.

However, this is what a Reader's Digest book titled, "Making the Most of Your Brain" has to say on the same subject:

In regulating the appetite the brain can match calorie input to energy output almost perfectly. In practice, the region of the brain that controls food intake is frequently overridden by conscious desires for food created by social and other pressures. But left alone, the brain provokes hunger only when glucose levels fall below the optimum level. In this situation, a person's weight would vary less than 5 percent during their entire adult life."

Very interesting!

It appears that hunger is a composite signal based on several inputs, the most important of which is mealtime.

We are conditioned right from birth to regulate our eating pattern. Infants learn quickly to sleep through the major portion of the night, because their mothers discourage feeding during this period. Perhaps, infants that resisted such learning, or mothers that were inclined to be indulgent, were all eaten up by predators thousands of years ago, thus producing the current
race of "infants-trainable-for-feeding-time" humans.

Anyway, mealtimes for human beings, and for at least some other animals, form a stable and regular pattern. It probably conditions us to be hungry at such times, modified by memory of what we have eaten at (and since) the last meal.

Signals from sugar levels or feeling of fullness probably reinforce mealtime response. Over time, our response about all these gets conditioned accordingly:

  1. Refractory period between meals, when the hunger-stimulus is suppressed.
  2. How much constitutes a full meal
  3. Which food items are appropriate at which meal

To the extent this description of hunger response is correct, it may explain the results reported in studies with amnesiacs. (Please see Dave Munger's post about the details. )

The results reported by Dave, however, crucially depend upon the assumption that the amygdala is not related in any way to hunger or satiety?

But amygdala is related closely to sense of smell, which turn is intimately connected with hunger and that complicates matters a bit.

The current issue of Reader's Digest (Indian Edition, June 2005) has an interesting article, "Follow your Nose", on the sense of smell.

It cites research by a Chicago neurologist, Alan R. Hirsch, and claims "... you stop eating a meal because your sense of smell and taste is satisfied, even if you don't feel full." It reports an ongoing study in which 92 participants lost an average of 15.25 kilos each in six months by stimulating their sense of smell! (More info is here.)

Another related question: "How do amnesiacs respond to sex?" Do they have no memory of it after a few minutes? Does that mean they can respond to sexual stimuli all over again, several times in a row?

Friday, June 17, 2005

A blog about Nature

Elizabeth Starr Hill writes a wonderful blog about nature.

Her writing has an exquisitely peaceful and unhurried quality, so lacking in all the text that is cut, pasted and processed for the online community.

Technorati Tags : , ,

Thursday, June 16, 2005

Automatic Blogrolls

Would it make sense to have Blogrolls that are populated and updated automatically with content similar (and/or complementary) to what a blogger is writing?

It would extend a blog with current and relevant content from elsewhere. It would also act as a trigger for ideas--in the blogger's and his readers' minds.

Do tell me if Google already does this and I haven't figured it out.


Technorati Tags : ,

Starting out or how things come together

This morning I discovered Qumana, a wonderful way to publish to your blog.

But Qumana does not work "seamlessly" with the site where I tried tentative first steps towards blogging. So must I abandon that site and start afresh on a platform that Qumana understands? Yes, it seems.

That also means giving up on RSS and adopting atom. So be it.

Who am I to blow against the wind?