Cardio vs weights for visceral and liver fat

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As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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A new study in the American Journal of Physiology revisits a very familiar topic — cardio versus weights — to determine which is better for reducing dangerous visceral and liver fat. A total of 155 subjects completed one of three eight-month training programs:

  1. Aerobic (AT): ~12 miles per week at 75% VO2max;
  2. Resistance(RT): 3 days a week, 8 exercises, 3 sets of 8-12;
  3. Aerobic/resistance (AT/RT): both the above programs combined.

At the end of the eight months, they used some pretty sophisticated tools to measure the outcomes, including CT scans to measure levels of visceral and liver fat. Here are some of the key outcomes:

And here’s how the researchers sum up the findings:

First, a resistance training program–even a very substantial one–did not significantly reduce body mass, visceral fat, liver fat or ALT liver enzyme levels. RT also did not reduce total abdominal fat, nor did it improve fasting insulin resistance. Second, in contrast to RT, a typical vigorous AT program resulted in significant reductions in visceral fat, liver fat and abdominal subcutaneous fat, and also led to improvements in circulating ALT and HOMA (fasting insulin resistance).

The results aren’t too surprising: as the researchers note, this particular aerobic training program likely burned about 67% more calories than the resistance program. It does seem a bit strange to me that adding resistance training to the aerobic training seems to make things worse rather than better — but the overall analysis in the paper says that AT and AT/RT are statistically indistinguishable. In other words, the weights add nothing. Don’t get me wrong: weights are useful for a lot of things, and this study was only testing a few specific outcomes. But on those outcomes — and they’re very important ones, particularly if you’re overweight — cardio trumps weights.

Post-exercise refuelling: all at once, or spread out?

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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We’ve all heard about the post-exercise “window” for refuelling to maximize recovery and adaption: you need to take in carbs and protein with 0.5-2 hours. But does the timing really matter for building muscle? A new study from Stuart Phillips’ group at McMaster University compared two tactics for post-workout protein intake. Once group took 25 grams of whey protein immediately after a set of leg-extension exercises; the other group received the same 25 grams of whey protein in 10 2.5-gram doses every 20 minutes for 200 minutes. They measured “muscle protein synthesis” — basically a very accurate way of assessing how well you’re stimulating muscle growth after a single bout rather than having to run the experiment for several months to actually see muscle growth — and found that it was much higher in the group that took their protein all at once. After six hours, protein synthesis was elevated by 193% in the single-shot group and just 121% in the prolonged group.

The question this study was seeking to answer actually relates to the difference between whey protein (which is absorbed quickly) and casein (which is absorbed more slowly: the 2.5 grams of whey every 20 minutes was chosen to mimic the absorption pattern of casein). The problem is that if you compare two different proteins in a study, then you’re changing a bunch of different factors at once — the absorption timing, but also factors like the amount of leucine, a branched-chain amino acid thought to be key for muscle growth. Since both groups received 25 grams of whey (and thus identical amounts of leucine), this shows that absorption rate is key.

Practical takeaway: this was a muscle protein synthesis study, not a training study, so you have take the results cautiously. But it does suggest that if you’re trying to build muscle, taking in a big dose (i.e. 25 grams) of protein as soon as possible is preferable to snacking over the course of a few hours. It also confirms previous findings suggesting that whey (found in dairy products) has some advantages over other protein sources.

Timing of baking soda loading, and the future of fatigue research

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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I spent three days last week at a conference called “The Future of Fatigue in Exercise,” hosted by Frank Marino and Rob Duffield at Charles Sturt University in Bathurst, Australia. Lots of interesting presentations and discussions, which I’ll be writing about in various forms over the next few months. To start, I thought I’d share a couple of short “practical” tidbits of research-in-progress that were presented at the conference. First: the timing of baking soda loading.

The practice of taking baking soda to buffer acid-base balance in the blood for short-duration exercise has been around for at least 30 years. It’s commonly used by athletes in events lasting around 2:00 (like 800-metre running), and may also help with repeated-sprint ability. Does it work? The research isn’t clear-cut, but most sports scientists believe that it works to some degree. The problem is that it also messes with your stomach, causing diarrhea and other lovely effects that aren’t conducive to great performance. (Random aside: I actually got my “big break” in university when one of my teammates had to bail out of the 4x800m relay team at the conference championships because he’d taken too much baking soda. I was inserted as a last-minute sub and ran a breakthrough race, earning a spot on the team at nationals. But I digress…)

Anyway, Jason Siegler of the University of Western Sydney presented some data looking at the timing of soda loading. Usually athletes take soda about an hour before competition, so that levels of of bicarbonate in the blood peak roughly when you’re competing. This also happens to be when gastrointestinal symptoms peak. What Siegler and his colleagues had noted in previous experiments was that bicarbonate levels actually stay high for several hours, while stomach problems tend to subside after a few hours.

So they ran a test of repeated sprint ability where the subjects took baking soda either 60, 120 or 180 minutes prior. As expected, the levels of bicarbonate in the volunteers’ blood before exercise were essentially identical no matter when they took the baking soda. The incidence and severity of gastrointestinal symptoms peaked about 90 minutes after taking the soda, and returned to normal after 180 minutes. All three groups performed essentially the same in the sprint test.

I should point out that there was no control group, so this study doesn’t tell us anything about whether the intervention works or not. Also, the stomach problems don’t appear to have hurt performance in the actual sprints, despite reaching an average of 5-6 out of 10 of the scales of incidence and severity. Apparently the volunteers managed to grit their teeth, clench their cheeks, and get the job done despite the discomfort. Still, if I was a middle-distance athlete inclined to try my luck with baking soda (and, for the record, I never did try it — in fact, when I was competing in the 1990s it was briefly listed as a “banned technique” by doping authorities, though they obviously couldn’t make baking soda a “banned substance”) — anyway, if I was using it, these results would certainly encourage me to take it ~3:00 before competition to hopefully give my stomach a chance to settle down.

Cryosaunas, frostbite and Justin Gatlin

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

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Just last week, I posted about the first serious study on the use of “cryosaunas” for post-workout recovery. Now I have an important update for athletes considering using a cryosauna: make sure to take off any sweaty clothes before you enter the sauna! According to AP, Justin Gatlin, the 2004 Olympic champion sprinter (and convicted doper), has arrived in South Korea for the World Championships sporting a serious case of frostbite caused by wearing sweaty socks into a cryosauna:

“You wake up at 9 o’clock in the morning in Orlando and it’s already 90 degrees,” said the 29-year-old Gatlin, who lives and trains in Florida. “So we’re already hot, drenched with sweat. Get in the booth, socks were wet, socks froze to me instantly.”

[…] Gatlin said the pain from the frostbite had subsided and the injury hadn’t affected his stride. But it is still bothersome because the wounds on his heels are near the level where his socks sit and where the back of his running spikes touch.

“It’s better than it was. It was all pussed up and blistered. It bubbled up and it stayed bubbled up for a good four or five days,” Gatlin said, lifting up his sweat pants to reveal the scabby scars that resemble big blisters.

So there you go: using liquid nitrogen for post-workout recovery has some downsides. Who knew?

Can you trust the calorie counts on exercise machines?

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

After an interesting e-mail conversation with Dr. Yoni Freedhoff of the pull-no-punches Weighty Matters blog, I ended up writing a guest post about some of the factors you need to think about if you ever look at the calorie number that your treadmill (or elliptical or exercise bike or whatever) spits out. Without giving away too much, I’ll say this: if you’re not considering the difference between gross and net calorie burn, you’re kidding yourself! READ THE FULL POST HERE.