Tag Archives: insulin resistance

The incredible camping experiment, circadian proper

Entrainment of the Human Circadian Clock to the Natural Light-Dark Cycle (Wright et al., 2013)

Abstract (edited): The electric light is one of the most important human inventions. Sleep and other daily rhythms in physiology and behavior, however, evolved in the natural light-dark cycle, and electrical lighting is thought to have disrupted these rhythms. Yet how much the age of electrical lighting has altered the human circadian clock is unknown. Here we show that electrical lighting and the constructed environment is associated with reduced exposure to sunlight during the day, increased light exposure after sunset, and a delayed timing of the circadian clock as compared to a summer natural 14 hr 40 min:9 hr 20 min light-dark cycle camping. Furthermore, we find that after exposure to only natural light, the internal circadian clock synchronizes to solar time such that the beginning of the internal biological night occurs at sunset and the end of the internal biological night occurs before wake time just after sunrise

In other words, they compared circadian events during 2 weeks of normal life to 2 weeks of 100% camping.  And camping won.

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Physiological Insulin Resistance in Circadia

If you haven’t read Petro Dobromylskyj’s posts about Physiological Insulin Resistance, then just go do it.  Highly recommended.
I’ve written about it as well, albeit in a slightly different context:
What is our proper “natural” diet?
40 years ago a group of researchers turned ketosis into poetry.

But now on to more pressing matters.  In the food deprived state, Physiological Insulin Resistance develops, in part, to spare muscle (yea yea yeah and glucose for the brain).  But how much of this is due to ‘food deprivation’ per se as opposed to something else… like circadian rhythms.

Exhibit A. Hat tip to Dr Kruse for writing about this TED talk.  In it, Jessa describes a crab that lives on the beach; scurries up the beach when the tide comes in and back down when it goes out.  Scientists captured a few, flew them halfway around the world and put them in little tilted cages.  The crabs still scurried up & down, in time with the tides.

Exhibit B. Evidence that the lunar cycle affects human sleep.  People tend to sleep a little less during the full moon.  Subjects were recruited to a windowless sleep lab and had no exposure to sun/moon/anything outside – they maintained this circadian rhythm for 3 days  (Cajochen et al., 2013).  Different from the crabs, but similar (in a way).

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Insulin resistance

Why it is important and what you can do about it, Op. 105

 

This post was largely inspired by a recent manuscript by Chris Gardner.  He’s an outside-the-box thinker and if you haven’t heard of him, check out this YouTube video: The Battle of the Diets: Is Anyone Winning (At Losing?)

Part I.  

Type II diabetes is the clinical manifestation of insulin resistance.  It is preceded by obesity (except in the cases of MONW & NOD), and caused by poor nutrition.  Markers of insulin resistance are: 1) impaired fasting glucose; 2) impaired glucose tolerance; and 3) elevated HbA1c.  THIS is why it is important: in 2009, Barr and colleagues showed a linear relationship between all three of these risk factors and all-cause mortality in the AusDiab study.  All.  Cause.  Mortality.

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