I am glad you are bringing this up. It's impossible to cheat and skip training. I started running alpine trail (ultra) marathons three years ago, and every time I go for a >40km run in the Alps, the hammer of reality just comes down fast and hard on both mind and body.

In the beginning I have grand plans of finishing near the peak of the Gaussian distribution of my age group. After 10km I am cursing myself for not training more. After 20km I am just focusing on finishing, and after 30km on not dying.

I thought capacity for taking in oxygen[1] was a general indicator of fitness. But then again, I haven't looked into this since highschool 15+ years ago.

[1] https://en.wikipedia.org/wiki/VO2_max

What about powerlifters or weightlifters? Super strong. Get winded walking up a flight of stairs.

My point is, there is no one universal definition of fitness.

The most reliable measure I've heard of is belly fat, which you can measure with a calipers. But you can't wish away belly fat with positive thinking, so I think the writers of this article are taking this study a little too far, IMO.

> What about powerlifters or weightlifters? Super strong. Get winded walking up a flight of stairs.

Sounds like a myth people believe about weight lifters.

Belly fat would be a poor measurement of a lot of powerlifters fitness as well.

The article seems to be mixing up "fitness" and "chance of death", which, while they are related, are probably not as directly correlated as they seem to be in the article.

Yes, the article seems to take liberties from the two studies it quotes.

But I also am skeptical of the underlying studies. So many factors in mortality rate I'm having a hard time believing they were able to control for all of those (weight, age, diet, exercise, family history, etc) and isolate "positive thinking."

Belly fat sems like a very unreliable proxy too. You can definitely be skinny without being fit in any of the usual senses, and you can have a fair amount of fat while still having good cardio, strength, etc.

I think VO2 is a piece of a bigger fitness puzzle. With runners you also need to factor in lactate threshold. Not to mention running efficiency/economy.

At the high level I think of fitness as the combination of: Speed, Strength, Power, Endurance, Flexibility, and Balance.

Then athleticism would include all of the fitness indicators plus some sport-specific technique and skill (or proprioception).

My Dad, who had done 5 marathons, won the Ironman lottery to participate in the world championship. He still spent a year training all the time to finish it, and not at a competitive time. My point is that you are absolutely right.

> used blood pressure and weight (among others) but those can vary wildly based on genetics and diet, I’m not sure they’re reliable indicators.

Should be reliable enough

You can't claim to be exactly fit if your pressure is 180/120 or if your BMI is high (unless you're obviously an exception - and most of those that complain about BMI aren't)

Blood pressure is useful, but I strongly dislike BMI. My weight hasn't fluctuated by more than 2kg in 10 years.

10 years ago I was playing competitive rugby, basketball and training for the former 3 times a week and was genuinely very fit. Now, I've got a decent amount of fat on me and am no-where near as healthy as I ought to be. Yet my weight and height haven't changed, so neither has my BMI. Nonetheless, I've lost a reasonable amount of muscle and instead put on a lot of fat.

On the other hand, my blood pressure definitely has got worse.

BMI is only useful for large populations but terrible as a metric for individuals.

For starters, it can't distinguish between muscle and fat. So anyone muscular is obese per BMI.

More: https://fivethirtyeight.com/features/bmi-is-a-terrible-measu...

This "can't distinguish between muscle and fat" thing is repeated quite often, but... I think it's pretty clear that the exceptions are reasonably obvious. As a proxy measure, I personally haven't written off BMI. Yes, the man or woman with a visible six-pack and muscular arms and legs with a BMI of 27 is probably fine, even though they're considered "overweight". But, no, the software developer whose exercise consists of walking from the car to his chair in the office with a BMI of 30... they're probably not exempt.

The linked article talks quite a bit about waist fat being explicitly bad. That's an interesting measure for me (the waist/hip ratio) and as someone who's currently hovering around a BMI of 26 (and is average fitness), I plan on making that waist/hip measurement when I get home tonight and seeing how measure relative to their research.

I've been planning to start a bit of a weight loss program (primarily food focused with maybe a 10-20% exercise increase) and if there's specific concerns related to waist fat then I'll do some more research on how to address that.

Even for large populations BMI is a pretty mediocre metric since it is heavily influenced by length.

The formula is kept simple `weight / height^2` to help 19th century doctors. A more accurate growth rate for healthy weight is something like `weight / heigth^2.5` [1]

This oversimplification causes standard BMI treshholds to underestimate obesity for short people (<1.6m), and overestimate obesity for tall people (>1.8m).

[1] https://people.maths.ox.ac.uk/trefethen/bmi.html

That changed drops my BMI two points, and as a tall person, really seems more in line with where I'm at weight wise. The goal for a normal weight is actually realistic and attainable. I've noticed that tall people only seem to be within the normal BMI range if they are the slender sort - if you look a more normally proportioned tall person you're automatically overweight, and very little extra weight put you in the obese category.

Interesting, for a 2.0m tall person, for a BMI of 22 (normal) you should weight 95kg instead of 88kg for the regular BMI

You can weight 108 kg (238 lbs) instead of 100 (220 lbs) for a BMI of 25 (top of the normal range). 18 lbs is quite a lot of difference, even at that weight. I stand at 198 cm's and hit 238 lbs last summer. At that point I had very little belly fat - 220 lbs would probably get me close to visible abs (the top few at least), which I don't think should be the top of the "normal" category.

It's an imperfect but useful proxy. It isn't valid as a single number that defines your health, but it correlates very well with obesity. Waist size is probably a more useful metric because of what we've learned about the health implications of visceral fat.

The number of people with a BMI over 30 who aren't obese is extremely small and they're very easy to spot. Arnold Schwarzenegger and Lee Haney won Mr Olympia with BMIs of around 30. Dorian Yates and Ronnie Coleman had off-season BMIs of over 40, but they were the most muscular men in recorded history.

IMO, "BMI is meaningless" is the new "I'm just big boned". The select group of people who really are lean at >30 BMI know that they're a healthy weight, while a much larger group of people are simply using the imperfection of BMI as a means to delude themselves. I'm happy to be corrected, but I haven't heard of a single incident of someone being incorrectly categorised as obese and advised to lose weight by a medical professional simply because of their BMI.

> So anyone muscular is obese per BMI.

And that's why I said

> unless you're obviously an exception

Most of the time complaining about BMI is just an excuse for overweight individuals

If needed body fat can be assessed separately.

There is a difference between wishful thinking and motivation enough to actualize. I agree that one will most likely not roll out of bed and complete a marathon, but do not underestimate the power of belief. If one believes strongly enough, I have no doubt that the human body unencumbered by obesity can complete an ironman with no training. It turns out that fostering and synthesizing such strength of belief requires either a lifetime of devotion to meditation, the usual physical training athletes do (many mental journeys happen in this process as well), or fantastic cosmic circumstance.

Completely agree that in no way would this be a replacement for actual fitness.

The point that the mental state of mind has some impact on fitness is important though. First, it makes sense if you think about it because we know mental stress definitely causes unhealthy physical states.

Second, a healthy mental state leads to working out which leads to more fitness and healthier mental state, etc... It's a healthy cycle that is all connected, and for many people that first healthy mental state is the hardest part to change.

Agreed. It has an impact. And it helps you break through walls in training.

But I think the authors of this article, who cite a previous study got a little carried away. They cite a paper where researchers measured cleaning ladies after 4 weeks? You're not going from zero to hero in 4 weeks.

How they ate over that period probably had a far larger effect on their overall health than mental positivity.

And the lecture probably got them to be more health conscious over that period.

> The point that the mental state of mind has some impact on fitness

I don't think the study actually supports this; more likely mental state impacts stress hormone levels which change blood pressure, heart rate, and immune system activity. That is not the same as physical fitness.

The article focuses on risk of death with regard to fitness instead of an ability to perform in a sport.

Yes, you're right. The study is different than what the article says. The article is taking a leap of faith from that study to generalize, so, fair point.

But even for that study, I'm a little skeptical of their results. There are so many factors that figure into mortality, it's hard to believe a positive attitude can really be singled out as significant.

Diet? Age? Exercise level? Family history? Weight? Where does positive thinking sit on this list?

Whether you're using it as a proxy for fitness or mortality I think it's a questionable correlation, IMHO.