Delayed dusk, Seattle schools and the Qom

Two studies of delayed dusk and its consequences

Sleep seems to be more and more in the news, the less and less we get!  The adverse effects of electric lights are by now well-known, but most studies are performed on volunteers in strictly controlled conditions.  Depicted here are two extraordinary studies that took place in the “natural environment” of human societies, taking advantage of changing conditions over space or time.

The first study compared subpopulations of the indigenous Qom people of far-northern Argentina.  Electricity has many benefits for developing societies, but sleep apparently is not one of them!  The second study was an exceptional example of science impacting policy-makers, and yielding data afterward to confirm the benefits.  The 2018 publication of the “Sleepmore in Seattle” study led to follow-up articles in the New York Times, Washington Post, Seattle Times and NPR.

These studies were carried out by Dr. Horacio de la Iglesia at the University of Washington, and presented in his talk “Sleep after Natural and Electric Dusk” in our weekly Colloquium series at the Integrative Physiology (IPHY) Department at CU Boulder.

The kangaroo rat’s adaptable hopping mechanism

The kangaroo rat's adaptable hopping mechanism

This cartoon summarizes the versatile ways that kangaroo rats deploy their hopping machinery in the desert.  It is based on a presentation by Dr. Craig McGowan of his research.  In studies of animal movement, biomechanicians often describe the muscles and connective structures using a machine metaphor, which helps to identify key adaptations in how animals get around.  Faced with a diverse terrain and hungry rattlesnakes, kangaroo rats use their gastrocnemius or “gastroc” muscle (homologous to our own “calf muscle”) in at least three different ways.  These discoveries may also inform future developments in the design of more versatile lower limb prostheses for humans.

Dr. McGowan directs the Comparative Neuromuscular Biomechanics Lab at the University of Idaho.  His presentation “Built to Hop: Meeting the Mechanical Demands of Locomotion in the Desert”, was a part of the weekly Colloquium at the Integrative Physiology (IPHY) Department at CU Boulder.

You have six Achilles tendons

Cartoon representation of colloquium talk by Jason Franz at Integrative Physiology Department, CU Boulder, November 4, 2019

Your calf muscles are attached to your heel by a tendon — the Achilles tendon.  What you might not know (nor did I) is that each of your major calf muscles — the soleus, and the two heads (divisions) of the gastrocnemius — exerts force through its own subtendon within the Achilles tendon.  These three subtendons (six including both legs) can slide past each other, which allows each muscle to work independently.  That’s good news for walking performance, because each muscle is free to “do its own thing” without having to remain in “lock step” with the others.  Unfortunately, as we age, adhesions form among the subtendons, reducing their independence, and walking performance is reduced.

In his talk, Dr. Franz explained the problem and then introduced his laboratory’s current work on biofeedback techniques (using sensors on the calf muscles and, yes, a futuristic pair of glasses) which holds the promise of restoring some of that youthful gait performance, and thus, a longer period of independent living into advanced age.

The title of his talk was “Mechanics, Energetics, and Stability: Modifiable Factors to Preserve Independent Mobility in Old Age”.  Dr. Franz directs the Applied Biomechanics Laboratory at the Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University.  The talk was presented at the weekly Colloquium at the Integrative Physiology (IPHY) Department at CU Boulder.