Transcript of "Max Peto at Health Extension Salon #1"
Short-Duration, High-IntensityInterval Training DramaticallyImproves Insulin Sensitivity Heath Extension Salon, 2012.09.13 Paper: Babraj, Timmons et al., 2009 Presented by: Maximus Peto
Format of This Presentation1. Review the aspects of disease that insulin is involved in (e.g. athero, cancer)2. Mention a paper (Timmons, 2009) showing HIIT improves insulin sensitivity3. Discuss an exercise intervention I developed to replicate Timmons’ insulin sensitivity enhancements, but with much less time/effort
Why talk about insulin sensitivity? Insulin signaling relates to many aspects of health and longevity, including: 1. Cholesterol synthesis 2. Cell division 3. Substrate utilization (oxidation (“burning”) of fat or carbs, depending on insulin status, among other things). This will then strongly influence body fatness, which influences inflammation and other disease factors Others (not discussed today)
[Insulin] and Cholesterol Synthesis Insulin + insulin sensitivity enables glucose to enter cells; insulin resistance prevents it High glucose (e.g. via insulin resistance) activates HMG-CoA Reductase HMG-CoA Reductase is the rate-limiting enzyme involved in cholesterol biosynthesis, and the target of cholesterol lowering drugs like statins I.e. Statins are largely prescribed for people with insulin resistance – DON’T BE!
[Insulin] and Cell Division (Specifically:Cancer Proliferation) Insulin is an anabolic hormone – required for cell growth and division Type 1 diabetics, despite high glucose, have metabolic and wasting problems due to lack of insulin production (glucose can’t get used) Many (most? all?) cancers need insulin signaling for cell division – this is one big reason why calorie restriction has been shown to inhibit cancer (CR enhances insulin sensitivity
[Insulin] and Substrate Utilization (WhatMacronutrients are Used as Fuel) Low insulin = burn fat; high insulin = NOT Insulin decreases autophagy (i.e. its lack enhances it!) Insulin increases lipid esterification (preparation for storage of lipids in fat cells – i.e. you get fatter) Insulin decreases proteolysis (which is why many bodybuilders eat high-glycemic diets – to retain muscle mass)
Measuring [Insulin] Indirectly – TheOGTT OGTT = “Oral Glucose Tolerance Test” 75 g glucose, dissolved in water Fast for 12 hours, drink glucose water Measure blood glucose every 30 mins for 2 hours (5 data points: 0, 30, 60, 90, 120 mins)
Measuring [Insulin] Indirectly – TheOGTT High glucose during OGTT most likely illustrates poor insulin action (e.g. secretion, sensitivity) Low glucose during OGTT suggests poor digestion (e.g. high fiber/low glycemic) or excellent insulin sensitivity, or both
Max’s Personal Experiments – Loweringthe OGTT and Postprandial Glucose I have tried many, many, many things to enhance insulin sensitivity (as measured by both OGTT, and fasting insulin), for all the reasons I’ve described before E.g. intermittent fasting, calorie restriction, low-carb diet, low-glycemic diet, exercise (low, moderate, and high-intensity), combining fat w/ meals (lowers glycemic index) among others. Lost 65 lbs back in 2007 (effective, yay!)
Max’s Personal Experiments – Loweringthe OGTT and Postprandial Glucose Achieved much better body fat and fasting insulin, but OGTT won’t change much (damn it!) Tried many things to change it Only found a single way to improve OGTT reliably – HIIT, the topic of today’s paper
Experimental Parameters in Timmons,et. al 2009 Take a group of healthy people, test OGTT before experiment Do exercise protocol: HIIT: bicycle sprint 30 sec, rest 4 min, repeat 4-6x in one session. Do 3 sessions/week for 2 weeks Wait 2 or 3 days (washout acute effects) Take OGTT again
Max Developed His Own Protocol Fast 12+ hours (e.g. overnight) Before breakfast, sprint as long as possible (15-30 sec), rest 60 seconds, sprint as long as possible (10-20 seconds) Rest until you feel like eating (~2-4 mins; you’ll be really out of breath, and maybe nauseous) Have breakfast; go about your day as normal Perform 3-5x per week
A Few Notes I measured glucose, NOT insulin. So this is actually representative of enhanced GLUCOSE DISPOSAL, which is related to, but not identical to, insulin sensitivity My glucose AUC findings were similar to what Timmons et. al found, so Im ASSUMING my insulin sensitivity is ALSO enhanced (I will be testing soon) I would like to do actual scientific study
Disclaimers! If you are trying this... Be sure you are in decent cardiac/vascular health. This is very strenuous, and you could give yourself a stroke or heart attack if you have current cardiac/vascular issues Jog 30 mins/day, 3x/week for 2 weeks before doing this, to get muscles ready EXPECT to be sore the next few days when starting (this goes away with training). I was sore in abs & hip flexors, but not now