|2011 Quad Cities Marathon|
The link mentioned a study in the Journal of Applied Physiology so I decided to hunt it down. Let's just say that JAP isn't a journal in my regular reading circle, so I was a little uncertain as to how to navigate the search. Fortunately the Advanced Scholar Search in Google Scholar came through. I pasted in the journal name, limited the search to articles published between 2010-2011, and added a few key words that I gleaned from the Runner's World link. The second hit that Scholar found was published on August 4, 2011 and entitled,
High intensity interval training alters substrate utilization and reduces oxygen consumption in the heartby Anne D. Hafstad et al. Looking at the abstract, I realized this must be the primary literature article on which the Runner's World tweet was based. My daughter calls me a 'running geek' and after you read the next sentence, you'll know why. I clipped the article into my 'Cool Running' Evernote Notebook for later reading, which I did the next weekend. I found the article to be detailed and interesting - interesting enough to write it up in this post.
|Figure 1. Substrate utilization data.|
|Figure 2. Mouseover sends to MarvinSketch.|
|Figure 3. Heart perfusion apparatus.|
|Figure 4. Metabolic substrate depends on exercise intensity.|
|Figure 5. Endurance training for mice.|
I now have better understanding of the metabolic and mechanoenergetic gains that accompany the discomfort of interval training. While I'm no expert in the topics covered in this post, I hope you see this foray as an example of learning in the wild. That's what we do in this blog. Before leaving the topic, I wanted to share two interesting, but somewhat random nuggets I discovered while researching this post. First, check out the treadmill used to train the mice (Figure 5). Curiosity got the best of me when I read "Modular Treadmill, Columbus Instruments" in the methods section of the article. A Google search on those words provided all the detail I wanted. Notice the 'stimulus assembly' near the mouse's tail. Adjustable shock intensity is not an option I want on my treadmill! Second, the molecular machine known as Complex I performs the first step in respiratory electron transport - the process that creates much of the energy that powers our cells. Complex I is the December 2011 Molecule of the Month on the Protein Data Bank pages. Mouse over the Jmol icon on the image below to obtain an interactive view of this fascinating, membrane-bound protein.
The schematic diagram below summarizes the important concepts mentioned in this post. Complete details of the metabolic reactions are available by mousing over a MarvinSketch or Jmol icon in the image. For additional information, please consult the list of resources at the bottom of this post.
|Schematic diagram of cardiomyocyte metabolism showing an enlarged view of a mitochondrion. Glucose and fatty acid metabolic pathways are highlighted in yellow and blue, respectively. Mouse over an icon to send an image to Applet. Adapted from J. Clin. Invest. 2005, 115, 547–555 doi:10.1172/JCI24405.|
- For an insightful review on cardiac energy metabolic pathways, check out J. Clin. Invest. 2005, 115, 547–555 doi:10.1172/JCI24405.
- KEGG pathway of glycolysis.
- The pyruvate dehydrogenase complex (PDH).
- KEGG pathway of fatty acid metabolism.
- KEGG pathway of the TCA cycle.
- KEGG map of oxidative phosphorylation.
- For details on the nomenclature of isotopically modified organic compounds see: Eur. J. Biochem. 1978 86, 9-25.