pdlamb

Interesting, large, though retrospective study, says good cardiac fitness is more important that avoiding cardiovascular disease, diabetes, or even smoking: https://health.clevelandclinic.org/b...e-study-finds/

Interestingly enough, for randonneurs and other "extreme" athletes, there's no upper limit. “'We found in our study there is no limit to how much exercise is too much,' says Wael Jaber, MD, a cardiologist and senior author of the study."

At first reading, this sounds like very good news. I haven't read the paper, though, so there may be some limitations that were skimmed over in the news release.

rubiksoval

No limit to how much low-end aerobic exercise is too much?

Because I don't for a second believe that racing flat out for hours at a time is good for you like elite cyclists, runners, etc., are prone to do.

DeadGrandpa

Is low-end aerobic exercise really the same as "racing flat out for hours at a time"? I'm far from being an elite cyclist, but I definitely enjoy hours of low end aerobic exercise, bicycling at a touring pace, 12-13 mph. It just seems that high end aerobic exercise is the realm of elite cyclists, not low end.

Hermes

Good article.

Here is another article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5514203/ Towards aging well: Use it or lose it: Exercise, epigenetics and cognition

I have been interested in epigenetic changes in DNA and the role of exercise. The article discusses HIIT efforts and their role on aging and longevity and how exercise up regulates genes.

Although many of the molecular pathways remain to be fully identified, here we discuss how physical activity and exercise is understood to produce changes in the human epigenome, which have the potential to enhance cognitive and psychological health, improve muscular fitness, and lead to better aging with improved quality of life in older age.

These authors concluded that that while strength training was effective at building muscle mass, high-intensity interval training (HIIT) yielded the biggest benefits at the cellular level. The younger volunteers in the interval training group saw a 49% increase in mitochondrial capacity, and the older volunteers saw an even more dramatic 69% increase. Interval training also improved volunteers’ insulin sensitivity, which indicated a lower likelihood of developing diabetes. These researchers therefore concluded that supervised HIIT appeared to be an effective recommendation to improve cardio-metabolic health parameters in older adults. HIIT produced a pattern of gene expression independent of age, a robust increase in transcriptional and translational regulation of muscle growth, induced a strong up regulation of mitochondrial proteins and improved the age-related decline in muscle mitochondria.

Humans may tolerate a lot of low intensity aerobic exercise and it has proven ability improve cardiac health, it seems that doses of high intensity interval training may prove even more valuable.

Machka 

Rowan had an accident in March. In the early days, the doctors thought he would end up in a full-care nursing home. He was in Post Traumatic Amnesia so long, his brain injury was classified as "extremely severe".

But he has amazed everyone. He is not fully recovered, but he has recovered a lot more than expected. And we're out walking and cycling (a little bit) again.

There were a lot of people praying for him from all over the world.

But he also had health and fitness in his favour.

• I was told that if he had been a smoker, he would have likely died or been in a vegetative state. But he had quit smoking over 20 years ago.
  
• Alcohol really slows brain recovery and causes numerous other problems ... but his alcohol consumption had diminished to just a few drinks a year, and he hasn't had a drink since the accident.
  https://msktc.org/tbi/factsheets/Alc...c-Brain-Injury
  
• His fitness level was good. Yes, he lost a lot of fitness, but he started at quite a high level. And there's evidence that exercise helps the brain.
  https://www.brainline.org/blog/getti...ou-should-care

That's enough to give us motivation to continue to lead reasonably healthy active lives.


And for me, through all of this, exercise has sure helped ease some of the stress.

rumrunn6

I can attest to a converse fact, that backing off exercise, has a negative effect on fitness

rubiksoval

No, it just said exercise, but not all exercise is equal.

Machka 

And the article I posted: https://www.brainline.org/blog/getti...ou-should-care

Says:
"The good news is that you don’t need to be a daily cyclist to get this benefit. Shared by the doctor who presented at our group, thirty minutes of exercise, three times a week, will release BDNF’s and speed the neuro healing process."

wolfchild

It all depends on the intensity and nature of the exercise...Sure anybody can do low-intensity cardio everyday but you can't do HIIT training and intervals and weightlifting everyday day for 365 days per year because it would be detrimental and counterproductive.

Seattle Forrest

You're probably right. But it's probably less bad to flat out race for hours than to sit for hours eating Doritos, like most people do.

Also, people evolved to be long distance runners, a human can run a marathon faster than a horse can. We didn't evolve to run 4 minute miles though, just enough to escape predators and run down big prey.

Hermes

There is this https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3538475/

In some individuals, long-term excessive endurance ET may cause adverse structural and electrical cardiac remodeling, including fibrosis and stiffening of the atria, RV, and large arteries. This theoretically might provide a substrate for atrial and ventricular arrhythmias and increase CV risk. Further investigation is warranted to identify the exercise threshold for potential toxicity, screening for at-risk individuals, and ideal ET regimens for optimizing CV health. For now, on the basis of animal and human data, CV benefits of vigorous aerobic ET appear to accrue in a dose-dependent fashion up to about 1 hour daily, beyond which further exertion produces diminishing returns and may even cause adverse CV effects in some individuals.

Maybe the first article posted is the further investigation warranted.

This animal study found that daily excessive, strenuous, uninterrupted running replicated the adverse cardiac structural remodeling and proarrhythmia substrate noted in observational studies of extreme endurance athletes. These findings support the hypothesis that in some individuals, long-term strenuous daily endurance ET, such as marathon running or professional long-distance cycling, in some individuals may cause cardiac fibrosis (especially in the atria and the RV and interventricular septum), diastolic dysfunction, and increased susceptibility to atrial and ventricular arrhythmias. Many previous animal studies have also found acute, adverse cardiac effects of prolonged (up to 6 hours) endurance exercise, sometimes employing a rat model of cold-water swimming in which the animals were forced to swim to avoid drowning.25 These studies are of uncertain clinical relevance because of the excessively stressful nature of the imposed exercise.

It is quite a jump from mice to men (or rats) but hey, maybe professional cyclists are close to rats in genetic makeup.

rubiksoval

Things like "The Haywire Heart" and multiple 20-something year old cyclists dropping dead of heart attacks gives me pause.

Dunbar

Carbonfiberboy 

This study just came out in JAMA, so I had another chance to look at it. I think some here might be misinterpreting the study. It's a study of 122,007 consecutive patients who had to take a treadmill test. They were ranked, not by volume of training or anything like that, but by performance on the test. IOW, you'd kill it. The ranking judged "Elite," the top 97.7% ranked by performance, had the fewest deaths from all causes over the next ~10 years. And as you know, you get to be elite by doing lots of intervals and riding your guts out. When I took mine at 72, with a left bundle branch blockage, I was ranked as a 47 y.o. highly fit individual, though the doc didn't give me my percentage rank.

Anyway, the bottom line is that there is no downside, in terms of all-cause mortality, to maximizing cardiovascular fitness.

mcours2006

I haven't had a chance to read the article, but there really are no down sides to exercise. If there is a magic bullet to your health it is exercise. Yes, too much of anything is not good for you, and for those people who spend an inordinate amount of time on exercise that isn't considered 'training' for a sport, there's probably some other underlying mental/emotional condition present.

chelvel

Sounds like a BS... He never heard about overtraining or that a big sport is unhealthy activity?

Those who live longer choose to exercise, not the other way round.

Machka 

Most people don't come anywhere near overtraining.


What's "a big sport"?

wolfchild

That's because most people don't train for performance, they just take it easy and exercise at a comfortable pace to burn few extra calories. Anybody who trains seriously can overtrain if they don't take enough rest....Hard training + busy demanding job + daily responsibilities can take it's toll on mind and body... and anybody can overtrain if they don't plan regular downtime, rest and easy days into their routine. Training hard for a specific goal and exercising are two different things.


My definition of " big sport" would be any sport activity where athletic performance and "numbers" becomes No.1 priority and becomes more important than health...Believe it or not, there are people who will sacrifice health in the name of performance.

mcours2006

NO!!! In cycling??? Who?

Carbonfiberboy 

Pretty funny to see how many people's opinions are unaffected by facts. I suppose we are just a subset of the Big World. Don't know why I would find it odd to see here. I mostly ride with what one might call "high-performance cyclists." I don't know of anyone who has ever overtrained. Over-reached, sure, but that's a normal part of training. One wants to do that once in awhile. If you never over-reach, you could be training harder.

gregf83 

Training is a self-limiting activity. Not many are motivated enough and have sufficient time available to overtrain.

chelvel

"Most" doesn't equal "All". And some just don't know that they are already overtrained.

It can start from here I think: "List of marathon fatalities". https://en.wikipedia.org/wiki/List_o...hon_fatalities

Again... "Not many" doesn't equal "All". Self-limiting can work differently with different people.

"We found in our study there is no limit to how much exercise is too much." Are they asking for fonds for a better study?

pdlamb

Do you know of any refereed study showing that overtraining or "big sport" reduces life span on a population?

chelvel

Nope. I don't care about life span of a population. I care about persons.

Do you know of any refereed study showing that overtraining or "big sport" not reduces life span on a population?

OBoile

The methodology you describe here actually gives me some pause. If the researchers were trying to answer the question "is it possible to do too much exercise" then simply measuring performance doesn't seem like a good way to go about doing this. First, performance and exercise volume, while obviously correlated, aren't the same thing. One person may be elite because they train 20 hours a week, while another may be elite because of 5 hours a week and great genetics. Second, assuming this is a slice of the general population, it is possible for many people to be "elite" without doing what many would consider an excessive amount of exercise.

Ultimately though, I have no doubt that the people doing too much are few and far between.