
When we work out rigorously, our bodies limit our ability to expend energy - johnny313
https://www.nytimes.com/2019/06/12/well/move/pushing-the-limits-of-human-endurance.html
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xchaotic
"runners were expending about two and a half times their resting metabolic
rate each day, a notable decline from the early days of the event, when they
were burning at least three and a half times their resting rate"

Not sure why they call the findings surprising. Body builders have known that
since before Schwarzenegger.

Body adapts and then you have to change the routine.

For long distance runners HIIT or just short, intense workout would be the
obvious answer to up the metabolism again.

~~~
luckydata
There's a trend of funding & publishing research that yields completely
obvious results and when you point it out you always get downvoted to hell on
HN, don't know why.

~~~
wutbrodo
It's because occasionally "obvious" claims are wrong, and having research that
confirms them gives us a firmer foundation of knowledge. The article mentions
that this is one of the first studies to quantify energy expenditure in this
way, which would mean it's bringing the "obvious" claims into the edifice of
scientific knowledge. Non-novel research results are an important (and
underrated/underincentivized) part of science.

The article may be leaning too heavily on claims that the results are
surprising, but that has little to do with the research.

~~~
Pulcinella
I do wish we could just buckle down and figure out diet and exercise related
health knowledge. So many diet and exercise related studies just have too
small sample sizes and are too narrow. This makes sense because it’s expensive
and time consuming to track a lot of people’s diet and exercise routines to
get rigorous results. I think, however, we should just bite the bullet and pay
$10 billion (or however much) to precisely track several thousand people’s
diet, exercise, sleep, etc and figure this out. Basically pay people as a full
time job to eat and do what you tell them (ethically of course. They aren’t
slaves. We just need better data than sample sizes of twenty people trying to
track their own health with self reported diaries).

~~~
jvagner
Most of what we need to know, for most of the population, we already know.

Even if the effort you suggested were to be done, the noise would continue to
distract in exactly the same way.

I've worked as a tech exec, and I've worked as a personal trainer, and I've
competed... we have the knowledge. We know how people can be healthy, we know
how people can live long lives, and we know how people can have bodies that
are a benefit to their lifetimes, not a burden.

I remember a study, it graphed a demographic of people across a scale from
"healthy" to "unhealthy". What they found was that people were heavily
represented on either end of the scale, but to a significant degree, not at
all in between.

So, the choice is... people's (barring economics, to some degree, I'll concede
-- though, being poor in other countries isn't the health catastrophe that it
can be in some first world countries).

~~~
wutbrodo
Yup, there's a lot of information that can seem to point in contradictory
directions, but you get some very, very clear signal out of it in a couple of
important directions.

People still seem pretty resistant to simple interventions like this though. I
think a big part of it is that most people have an incredibly powerful status
quo bias, and get extremely uneasy with diverging from the norm of behavior
they see around them (even if those norms are of generally far worse health
than they're targeting).

I've spent the last decade incrementally understanding more about nutrition
and optimizing my diet, and I've reached the point where the divergence
between mine and my friends' diets has become pretty insane. Not
coincidentally, now that we're starting to enter the period where age catches
up with our bodies, I'm by far the healthiest, by both appearance and
symptoms. I've had friends ask me what I do, but it's far enough outside the
norm that they assume it's impossible or that I have iron willpower (spoiler:
I really don't. If you eat healthy, your tastes shift towards healthy food).

This is a general problem with people; in the narrow case, it could be solved
by changing their environment (ie blanketing the country with PSAs with simple
messages, like we did for smoking). It would do infinitely more good to
somehow grant people the intellectual confidence (or indeed, capability) to
avoid blunt heuristics like the so-called "wisdom" of crowds, but I have no
earthly idea how one would do that.

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baybal2
Does anybody have the sane reaction as me?

I often feel much less hungry if I do some physical exertion than when I spend
day more or less still.

~~~
freetime2
Exact opposite here. I get much hungrier on days that I work out. I basically
need to eat an extra meal to not feel ravenous. Not great for weight loss
unfortunately.

~~~
naasking
Depends on the exercise. Cardio can suppress appetite for a time, resistance
training not so much.

~~~
loeg
In my experience cardio only suppresses appetite for the duration of the
cardio. So even running two hours a day (a lot more than most runners,
including myself, do), there's still ~14 hours of day to cram calories in my
face.

~~~
naasking
Depends on intensity. Vomiting after marathons and triathlons isn't uncommon,
and intensity that's slightly lower than that can still induce nausea which
can last awhile. Reactions to all sorts of training are largely individual I
think.

~~~
loeg
> Vomiting after marathons and triathlons isn't uncommon

Those are long distance, race intensity efforts. Most workouts aren't going to
be race pace and most runners for fitness aren't running marathon distances,
esp. not for every workout. In my experience, the nausea quickly subsides once
my heart rate drops below 190.

> Reactions to all sorts of training are largely individual I think.

Totally agree. I was talking about my personal experience (anecdotal).

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M2Ys4U
This study has a sample size of three. Worth taking with a large pinch of
salt.

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jl2718
The validity of “doubly-labeled water” results is dubious at best in an
organism with so many pathways to feed the citric acid cycle. Specifically I’m
referring to fat adaptation and protein catabolism. Also, how does
600*(3.5-2.5)=6200/3.5?

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nicky0
Is this not simply explained by the body becoming more econonmical at
repeating the same action over time?

After 6 weeks of daily running the body will adapt to be more effcient at
running, so won't need so much energy to perform the same activity.

~~~
Scarblac
I don't think so. For instance, pro cyclist have been doing nothing but
cycling training for years and years. And still, this effect shows up a few
weeks into a Grand Tour.

As they mention at the end of the article, from gorging research (eating as
much as possible to gain weight) it is _also_ known that the body can't ingest
more calories than about 2.5x times the normal daily energy output. So it's
more likely that that is the limiting factor -- in the first weeks you have
some reserves to burn, but when those are gone your body doesn't burn more
energy than it can take in.

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etiam
I wonder if this phenomenon can serve to explain burnout syndrome?

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twofig
This is also true wrt to fasting. I consumed less than 400 calories a day and
after 3 weeks my weight plateaued.

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manjana
Paywall. Can anybody give a tl;dr?

~~~
Existenceblinks
No needs to do anything fancy (to read it), just hit the refresh icon and
cancel it _almost_ immediately. Click-20ms-click.

~~~
oulu2006
Excellent! that worked first pop!

I'd be loading the paywall JS first before the content if I was running the
site.

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dreamer7
Nothing counterintuitive about these results. Anyone who has ever exercised
knows that he has to switch things up if he intends to keep breaking the
plateau either for strength or weight loss.

Our body is incredibly good at conserving energy which is why we feel less
tired running 5kms daily after a while.

Only interesting point is the barrier on how quickly we can reach this
efficiency with the limitation of how much fuel we can consume.

~~~
bradleyjg
I don’t know about counterintuitive but the article says they don’t know where
the savings are coming from. If we have the capacity to be more efficient why
not always be more efficient? Presumably there’s some trade off.

~~~
ZeroFries
Being more efficient during higher energy demands doesn't necessarily optimize
you for the same conditions with lower demands. It would be interesting to re-
calculate energy expenditure at rest for the over-exercised grouped.

