Michael Mosely again....

[Tom Lang]

Good episode last night about exercise. Made some good points. He did an exercise program wherein he rode a stationary bike as hard as he could for 20 seconds X 3; 3x per week, for four weeks (so 12 min total). Old news for us, but this HIT program improved his insulin sensitivity by quite a bit. (Turns out he's genetically a "non-responder," so his VO2max did not change.)

The problem is that the show did not address strength training. The idea, per the researcher on the show, is that HIT training creates such a glycogen demand that the muscles pull more glucose in from the blood. Wouldn't strength training do the same thing? Or is the metabolic conditioning effect the thing that makes the difference (chemical changes via conditioning, vs. architectural changes via strength training)?

No mention was made of reducing carb intake, either (on this, or the fasting show). They did show his blood lipids (literally, in a spun-down sample) after eating a fatty breakfast. After a 90 minute walk that evening, they repeated the test the next day, and the lipid layer in the centrifuge tube was much reduced. Interesting. Exercise good.

The breakfast was eggs, bacon, sausage, beans, toast, and some black disc things (this was an "English breakfast" eaten at a cafe in Glasgow). Again, no mention of the influence of his carb intake. I saw some creamy coffee, too; I'm only assuming he put sugar in it.

So I guess my questions are: does strength training influence insulin sensitivity; and, doesn't reducing carb intake both increase insulin sensitivity and reduce blood lipids?

Thanks, Jordan.

[Jordan Feigenbaum]

Strength training influences insulin sensitivity in a number of ways. 1) it increases expression and localization of the glut-4 receptor on the skeletal muscle cell thereby allowing glucose to be transported into the muscle cells without insulin, i.e. less insulin is required to clear a given amount of glucose from the blood at this point. 2) Increased skeletal muscle mass allows for a bigger depot of glucose to be stored as glycogen instead of "spilling over" and being converted in the liver to fat to be carried by VLDL. 3) Other things :-)

Reducing carbohydrate intake definitely influences blood lipids, but the changes in sum, are hyper-dependent on what the rest of the diet looks like, weight loss/gain, and other factors. Yea, if you spin down blood after a fatty meal and do the same test the next day fasted things are going to be a lot different, thanks Mike lol.

HIIT does some really cool things, especially if it's actually at a high intensity and high resistance (exercise bike or Wingate sprints FTW). Some research shows you can reduce muscle glycogen stores by 20-40% with one 30s sprint IIRC. You're also contracting the muscles rapidly and at high force too, which can lead to both chemical and architectural changes just like weight training. This is one of the reasons some researchers have found increased strength and power outputs in those who do HIIT.

[Tom Lang]

Cool.

Just to clarify the blood lipid thing, it went like this: Fatty breakfast, then first blood draw 4 hours later. No mention of lunch or dinner, but a 90 min walk that evening. Same thing the next day--breakfast, 4 hours, blood draw. The difference was the exercise.

I'll do Tabata intervals on an elliptical from time to time--5 more intervals than what Mosely did (Andy Baker likes the elliptical for its minimal effect on strength and recovery; I do to). Three seems to be adequate, is 8 (as in Tabata) too much? In other words, if a little (3x 20 sec sprints) is good, and more is better (is it?), how much is too much? On average, I guess I mean. Or take me: 5'-11", 195lbs, BF I'm guessing around 20%; DL 310 for a double, max squat was 265 for 3x5 (now working back up with proper form this time), and i can do 7 BW chins before failure.

When I do work in the intervals, it's usually after squat/pull day (4-day split). Or on rest days, 2x per week.

Thanks again!

[Jordan Feigenbaum]

More isn't better, better is better. Tabata is okay and can be brutally effective, however, in my opinion it's not optimal.

[Tom Lang]

More isn't better, better is better. Tabata is okay and can be brutally effective, however, in my opinion it's not optimal.

So what would be optimal? I'll take effective, or better, over brutal.

[Jordan Feigenbaum]

So what would be optimal? I'll take effective, or better, over brutal.

If the goal is strength/size while improving conditioning, 10-30s sprints, 1:30-2:30 rest, 4-8 repeats depending on modality, level of conditioning, etc. The harder, higher resistance, and higher velocity of movement the better.

[Tom Lang]

Nice, thank you.

[Tom Lang]

One more question: Is the rest "active," e.g. a slow pace on the elliptical between sprints, or walking if actually running somewhere?

Thanks again!

[Jordan Feigenbaum]

Doesn't matter at all.

[David1982]

Doesn't matter at all.

Would it work with sprinting as fast as one can, with no resistance like on the Bike?