Epidemiologic data from a 20-year prospective study of a large human cohort of
initially cancer-free participants revealed that exercise prior to cancer
initiation had a modest impact on cancer incidence in low metastatic stages
but significantly reduced the likelihood of highly metastatic cancer.
Data was gathered from a large cohort via questionnaire. Looks like the study then used responses to classify high vs low intensity.
From the article:
The total study population included 2,734 participants; 243 new cancer cases
were recorded during the 20-year follow-up period.
It reads as if the study then had to reject data from 95 of the 243 patients due to not having a SEER score.
From skimming the article, I can't find any analysis of metastatic disease incidence in the remaining patients? Am I just missing it?
The chief result being reported here is in the mouse model, it's not 100-some people filling out a questionnaire that got them on the cover of the journal.
Totally agree. I am extremely annoyed at the general article submitted versus the actual paper focus.
While I respect the need for these longterm survey data collection efforts, I am not sure I would frankly trust that survey to even accurately be able to tease out high-intensity vs low-intensity efforts from people participating in the study.
And the tie-in from the cohort survey results back into the motivation for the mouse study just isn't done at all. I mean out of their 148 patients with SEER scores, they make no mention at all at metastatic disease occurence or even attempt to tie that figure back to exercise intensity . . .
Is that true? The headline here comes straight from the human study. From the article:
> The human data, obtained from an epidemiological study that monitored 3,000 individuals for about 20 years, indicated 72% less metastatic cancer in participants who reported regular aerobic activity at high intensity, compared to those who did not engage in physical exercise.
That figure comes from examining 148 people in that cohort who got cancer. The authors don't state what proportion of that number is metastatic cancer. They also state:
"As our focus was on the relationship between exercise and cancer, we used a propensity score of multinomial logistic regression to control for key variables in the diet assessed using a validated questionnaire."
So the 73% figure is drawn from a small number of cases that were significantly weighted. I'd be interested to hear what people who know this field think about this result separate from the mouse/human exercise stuff.
Note, this isn't for all types of aerobic activity. They're specifically saying that high-intensity aerobics, such as sprinting, are beneficial.
> "Our results indicate that unlike fat-burning exercise, which is relatively moderate, it is a high-intensity aerobic activity that helps in cancer prevention," adds Dr. Gepner. "If the optimal intensity range for burning fat is 65-70% of the maximum pulse rate, sugar burning requires 80-85% - even if only for brief intervals."
That doesn't sound right. Even 95% of max heart rate is sustainable for a long, long time. Intervals one can only sustain for 30s are way above VO2max intensity deep in the anaerobic zone. Heart rate pretty much maxes out on those.
90% of maximum heart rate is the start of the anaerobic zone, and maintaining it for multiple minutes requires intense training. If you think you're sustaining 95% for any sort of time then that means you've failed to measure your maximum heart rate correctly.
This really isn't accurate at all. I'm in very strong aerobic shape and 95% of my max heart rate is not at all sustainable for more than a few minutes, and it is also a deeply anaerobic activity. VO2Max != max heart rate. Your heartrate @ VO2 max is typically much lower than your max heartrate. Max genuinely means max in this case, as in, literally the highest you can get your heartrate up. By definition, you are way above your VO2 max in that situation and it is not going to be sustainable for long at all.
Something like 90% approaches what you're talking about, maybe being sustainable for 15 minutes or so, but that 5% makes an enormous difference.
You might be right and my 95% was a bit off. But the main point is that 80-85% being sustainable for only 30s might only be the case for someone who is in absolutely terrible shape.
Don't think about actual pulse numbers and % of pulse numbers. If you're not thinking about quitting and almost falling off the rower you're not going hard enough.
You will think of every excuse known to man to avoid doing it.
Nope. A rough estimate of my old fart MHR is 169. 85% of which is 143. I run literally for several hours at this heart rate every week. The burning intensity you're talking about is at 100-110% of max HR.
How does one determine maximum pulse rate? I do workouts where I'm constantly at 160-170 bpm for 15 minutes and my lungs aren't burning nor am I about to collapse (aged mid-30s, if that matters)
Note that wearable fitness trackers that use wrist optical heart rate sensors often don't give accurate readings on such tests so it's best to add a chest heart rate sensor.
"Since HRmax varies by individual, the most accurate way of measuring any single person's HRmax is via a cardiac stress test. In this test, a person is subjected to controlled physiologic stress (generally by treadmill or bicycle ergometer) while being monitored by an electrocardiogram (ECG). The intensity of exercise is periodically increased until certain changes in heart function are detected on the ECG monitor, at which point the subject is directed to stop. Typical duration of the test ranges ten to twenty minutes."
If you need an accurate number, it should be measured manually. Some sports clinics can do this; measuring true VO2 Max, as well as actual max heart rate.
I've heard that estimate before (80% would be ~150bpm for me). But then the physiological effects described by the GP don't seem right as I need to go much higher to feel anything like "my lungs burning" (maybe 190+?)
Age based equations for maximum heart rate are mostly bullshit. More recent research has shown that there is much less decline in maximum heart rate with age, at least for athletes with a decent level of fitness. And there is a huge amount of natural variation between individuals which is often more significant than age effects.
Maximum heart rate is also sport dependent. For an equivalent level of fitness, maximum cycling HR is often about 10bpm lower than maximum running HR. This is because running engages more muscles and doesn't restrict breathing as much.
Yeah, not saying it’s a perfect rule, just making the point that the parent’s 160-170bpm is lower than what I’d expect his max to be, using the rule of thumb a lot of people know.
(And for what it’s worth, my max heart rate is the same when cycling or running, within a small margin of error. I’ve never thought to ask anyone if it’s the same for them - I will do now!)
> just making the point that the parent’s 160-170bpm is lower than what I’d expect his max to be
Just want to clarify, I mentioned 160-170 bpm as a regular workout I do where I do not feel anywhere near max (I have seen my heart rate get above 190 while running).
I was replying to this:
> For 80-85% of maximum pulse rate...
> If your lungs are burning and you're about to collapse after 30 seconds of activity the intensity is about right.
And saying that going at 160-170 (above 80-85% according to rule of thumb) for a prolonged period of time, I feel none of those symptoms.
For my whole life i sustain 195-200 for 1h. Im 40+ now and run a 10k a day (45mins). Even a very slow 10k (1h) i never go below 170 after the first 5 minutes.
I wouldn't suggest using swimming to calculate your maximum heart rate, as you have less control over when you breath. Also, you don't want to be out of breath anywhere near water, the potential for passing out and drowning is too great.
Just put on your heart rate monitor, get warmed up, and then sprint as fast as you can until you collapse, most easily done by sprinting uphill. Note your maximum heart rate recorded.
Just hill sprints will get you a better read than 220-age, but the reason, I believe, lab test build up heartrate gradually is that you don't want to test the abilities of your leg muscles to sprint and recover.
Very well trained athletes will notice that they bounce between different body systems limiting their performance as the move through training periods.
Swimming can work as well, but only if you have good technique. I'm not a great swimmer so when I'm panting by the poolside it's because I wasn't breathing correctly, not because I was exceeding my aerobic capacity. Highly trained competitive swimmers don't have this problem.
I believe running your heart at such high intensity every day isn't particularly healthy. It causes scarring of the heart tissue and possible problems as you age.
5-10 minutes of high intensity exercise daily is well outside what that Ted talk was describing.
With up to 45 minutes of daily exercise you see an improvement. After that there is a period where more exercise has negligible impact and only at the extreme upper end to you see a decline. But even people running regular marathons have lower risks than couch potatoes, you need to get really extreme before it’s an issue.
“First, low exercise is a much more prevalent problem for our society than is excessive exercise. Second, the maximal health benefits of exercise typically occur at quite low levels. More exercise may burn more calories and improve athletic performance, but probably does not lead to better health outcomes.
“Three, in keeping with what Ben Levine said in his Circulation Commentary in 2014, I do not believe that we should go overboard to frighten athletes who want to compete in vigorous endurance sports like marathons and triathlons.”
Lavie also pointed out two new exercise studies in JAMA Internal Medicine....
When mortality rates were adjusted for exercise levels, the researchers found the lowest rate among those who exercised about three to five times the amount recommended by federal guidelines (i.e., 150 minutes per week of moderate exercise, or 75 minutes of vigorous exercise like running). However, the increased benefit of working out three to five times more than the guidelines was modest, the researchers wrote.
More importantly to serious runners, there was no evidence of harm at ten or more times the recommended minimum.
Another JAMA Internal Medicine paper looked at mortality rates in relation to moderate vs. vigorous exercise. In other words, what’s the proof for the federal government’s guideline showing vigorous exercise is roughly twice as good per minute as moderate exercise (75 minutes vs. 150 minutes)?
The conclusion, based on an analysis of 204,000 Australians aged 45 to 75: The current federal guidelines likely underestimate the value of vigorous exercise. The Australian results showed an inverse relationship between vigorous exercise and mortality rates.
It's absolutely better than nothing. If that's all you can do, keep doing it.
But it's far less than ideal.
Unfortunately, long, low intensity cardio (zone 2 on the order of 4 hours per week) is also incredibly important for longevity and health. You also ideally should be doing some kind of real strength training (e.g. barbells) for 1-3 hours per week for long term well being. A good maximum strength building program is usually going to require 30-60 minutes 2-3x a week. Muscle mass degradation is one of the most significant factors affecting quality of life in later age. You mitigate this decline by a) maximizing your potential in your youth and b) doing consistent maintenance work in your middle to late age.
Again, something is always going to be better than nothing. Sadly, our current society doesn't really allow for people to get an adequate amount of exercise, at least for many white collar workers with families.
That would explain the relationship to glucose consumption as noted in the subheading of the article . In events like sprinting, the glycolytic pathway is the primary one.
This also seems somewhat related to the fact that we inject an irradiated glucose analog to make certain types of malignancy show up better on a PET scan (re: Warburg effect)
One issue with the intensity thing. In my experience, as you age, it gets harder, and harder to up the intensity without incurring injury, and if you're injured it's harder to exercise at all.
As an aging (50-something) fitness nazi, the key to this is having several different activities of varying impact levels that you can use to attain high intensity. Spinning classes, running, swimming, HIIT / Crossfit derivatives (man be careful with that though), or the elliptical machines. Even aqua aerobics can work well.
And I don't think you need a 40 minute zone 4 workout. You can probably do intervals in zone 4 with as much recovery as you need over 20 minutes and induce a lot of (beneficial) stress. Interval training is the key to really good fitness, especially on limited time budgets.
I used to tackle this issue by spending more time warming up than actually exercising.
I am now using specific strengthening exercises from the kneesovertoesguy program to make my lower body more robust. I am not spending a lot of time on this but am seeing encouraging signs where I can engage in more vigorous activities with less warmup and less pain. If you have any pain (other than muscle exertion pain) during exercise, or even joint discomfort, etc, that's a potential road to injury that you have to step back and address. I stopped lifting heavy weights for now while I focus instead on improving my weak spots.
Pretty great thing to read coming back from a tempo run! I just go into it this year, and I'd like to say, it's more fun than I thought. Every aspect.
If you get a heart rate monitor and dive into what you're doing even difficult high intensity runs are enjoyable. It's all about expectations and if you go into it thinking
- "I'm going to run at 75% of my max heart rate" you know you're going to be winded, but at the end feel great
- "I'm going on an easy run 60% of max heart rate" you know you'll be able to have a nice conversation along the way and get some good thinking in
etc etc, it's great. Don't start with a heart rate monitor but after a few months it adds a lot of fun for those who like geeking out on numbers and planning.
I have a few opinions about distance running. A coworker explained it has a way of turning down the volume on the rest of your perception. Something about running 10 miles makes other problems less anxiety inducing. They're still important, they're just not, like, scary.
If you consider distance running, get good shoes. go to the kind of place that puts you in shoes, and videos you running on a treadmill. Some people are biomechanically sound. I'm not. I need a lot of support to keep my ankle in line with the rest of my leg. Get good shoes and replace them when needed.
You can run anywhere, but pay close attention to the surface you're running on. It's very subtle, but running on a concrete sidewalk is different than running on asphalt right next to the sidewalk. try to run on dirt if you can, it's easier on your body. It also takes a while to really get a good sense of what is normal and what is excessive.
Pay attention to your muscles joints and tendons, take rest days, and cut runs short when you need to. I've called to have someone pick me up, because my legs were done. It can take a while to figure out when you're just dealing with normal "running sucks" and when you're actually pushing the red line where you're damaging things.
I completely agree on all of this. I had an on again off again relationship with running before this year and it’s because… I ran in the same shoes for 8 years and I’d stop when my hip or knee felt off. Got new shoes this year and I’ve done more running than I ever had with no issues. Shoes only last 250-500 miles!
Definitely agree with pain as well, there is good pain and bad pain and tendon pain is never good pain.
It might be individual but to me running is just unbearably boring either way (as is most repetitive exercise), it just gets real old real fast. Spending a lot of energy bicycling is a bit more fun though.
Have you actually tested your max heart rate? I work out with a HRM for Zone 2, but I'm just going off of Polar's zones.
From what I understand going more in depth requires either maxing out your HR (Steve House describes how you can do this in Training for the New Alpinism - basically sprinting uphill until you collapse, seems really unpleasant) or doing lactate testing in a lab.
Getting an accurate HR Max can be useful…I got into running several years ago and struggled early on with the zone based training recommendations until I realized it was just because my max HR was higher than the various apps estimate by default.
After running my first 5k race all-out, I recalculated my training zones based on a max of 205 instead of the 190 that the apps had estimated for me, and things started to make a lot more sense.
You can easily test relatively accurate max heart rate just by running a 5K race. Run a slightly slower than race pace, and go as hard as you can at the very end (last 1K) with the goal of sprinting to the finish line and vomit. It's unpleasant, but relatively safe during a race event with medical staff there at the end.
Also, max heart rate is only useful after you've been running for awhile. If your body hasn't started adapting to the change, MHR doesn't do much and often inaccurate. It's like 1RM in lifting, 1RM is meaningless in beginners as their bodies and central nervous systems haven't learned to fire all the muscles yet.
You should check out doing an Aerobic Threshold (AeT) test and an Anaerobic Threshold (AnT) test. I believe there are details on the Uphill Athlete site. But you should absolutely determine your AeT if you’re trying to base build in zone 2 (180-age is a good place to start, but it is likely lower). AnT is useful as well for higher zone training. It’s a more demanding test than AeT but will give you a more practical upper bound for speed workouts than max HR.
For my part, my Garmin estimates my lactate threshold heart rate. Whatever its accuracy, I find it's as good a number as any to set zones around. Otherwise, I have a good estimate of my max heart rate from a couple of times I've hit it incidentally, such as during a race. Max heart rate hurts, and it's not a place to go to during normal training.
A max HR test can be done on a treadmill in a gym too.
Unless you're used to reaching your max HR during exercise - something I don't suggest - it will be painful, but you're not supposed to hold your heart rate at this level for long either, just long enough for the heart rate sensor to register that level.
Some cancers are glucose-sensitive which use glucose to grow.
Some cancer patients go on a keto diet instead of/as well as aerobic activity (a keto diet is probably better tolerated than lots of aerobic activity for many cancer patients).
This dependency on sugar distinguishes cancer cells from normal cells and is often used as a treatment option to kill cancer cells. In reality, the results have not been encouraging. Not all cancer cell types are sensitive to the removal of sugar, and even for the cancers that are sensitive, sugar depletion only slows down the rate of cancer progression. The pathways that sensitise cancer cells to sugar deprivation remains poorly understood.
Cancer needs fuel, it is after all a patient's cell gone rogue. A patient could starve themselves and the cancer would stop growing-- but so would all the other cells. My personal discussions with trained professionals is that patients should eat what they need to stay healthy and content.
>> And like any notable differences between tumor cells and regular ones, there have been attempts to exploit this metabolic change for cancer therapy, but that's been difficult to realize. It can be tricky to throw a wrench into glycolysis without messing up energy homeostasis in general, for one thing, and some of the more indirect attempts have not had clinical success. As that last linked paper outlines, even the reasons behind the Warburg effect are not completely clear - the low-oxygen story makes sense, sure, but there are tumors that don't seem to be oxygen-deprived that also show it.
Low carbohydrate diets may be a good option to improve general health for many people, however they haven't generally proven effective as cancer treatments. The clinical trials have been disappointing.
When you're in the midst of trying to find your way through a cancer diagnosis, this statement can be incredibly frustrating. It basically turns into a cop out that medical providers use to wave off any discussion or exploration of a topic. And even if it's been proven to be effective, there's some way to slice your specific case such that it wasn't tested in the trial. Oh, you're BRCA positive? Somatic? Platinum resistant? Recurrent? Have or have not undergone this very specific therapy? Well, the trial didn't cover you so its not proven.
I totally understand why, few doctors would likely want to talk about phase of the moon or rubbing crystals...but in the context of cancer treatment, the lack of any clear guidance or recommendation about diet beyond basic USDA recommendations is maddening.
Even if blood sugar level dips during the exercise it comes right back immediately after. Even if you exercise a lot, for majority of the day your blood sugar level should be nominal because nobody can exercise at the effort needed to dip your sugar for very long.
So does this mean cancer cells are so hungry for sugar that they can't survive even a short term dip in sugar availability?
> So does this mean cancer cells are so hungry for sugar that they can't survive even a short term dip in sugar availability?
It's not a short-term dip, according to the article:
> "Examining the cells of these organs, we found a rise in the number of glucose receptors during high-intensity aerobic activity - increasing glucose intake and turning the organs into effective energy-consumption machines, very much like the muscles. We assume that this happens because the organs must compete for sugar resources with the muscles, known to burn large quantities of glucose during physical exercise. Consequently, if cancer develops, the fierce competition over glucose reduces the availability of energy that is critical to metastasis."
> "Moreover," she offers, "when a person exercises regularly, this condition becomes permanent: the tissues of internal organs change and become similar to muscle tissue."
I.e. exercising lots appears to change the makeup of your organs, so they absorb sugar more aggressively _all the time_ and so cancer cells have to develop in a far more sugar-competitive environment.
I'm no doctor, but it makes sense why exercise is also prescribed for countering diabetes in that case. If organs and muscles are "hungrier" for glucose when routinely exercising it seems like it would regulate blood sugar levels.
Surely there have been studies on simple carbohydrate intake correlated with cancer incidence? I suppose it's hard to do a multi-decade study on something like this but it may be possible to gain evidence.
If anyone is looking for an easy way to get their heart rate up to max + exert themselves at max effort without doing anything too crazy, I highly recommend a C2 rowing machine. Set the program to a 5K (or 2K) and do the first half as a warmup, then go all-out for the second half. You'll easily hit your max heart rate and can try to sustain it for a minute.
Doing this only takes 10-20 minutes depending on the length of your warmup, and you'll be working your entire body + cardio + lungs. Just make sure you are using correct form - start slow before going all out.
I run and road bike, but rowing is easily the most efficient way to get into that HR zone quickly. You can do sprints but that's pretty hard on your legs if you aren't an active athlete. Rowing is low impact by comparison.
IMO, do not expect to do this right after unboxing. Realize that figuring out (and strengthening your muscle to use) the correct form takes a bit of time, and if you jump into a 5k row and you aren't feeling it in the right places/it's super easy, you absolutely are not using the right form. Rowing targets muscles most people never use, especially in your back, and it should be quite fatiguing.
Wouldn't be much easier just restrict sugar/glucose consumption, so you don't need to burn it by exercise? I feel this is trying to solve consequences instead of the cause, if I read the article correctly.
Keto is a successful form of cancer treatment mostly for brain cancers. Low carb/keto haven't shown dramatic benefits for cancer treatment (like most treatments, it helps some people) or for cancer prevention.
Exercise seems to fix cancer at the source as indicated by studies showing it dramatically reduces cancer risks. So IMHO restricting carbohydrate is trying to solve the consequence of excess energy through diet whereas exercise solves it at the source.
Exercise causes a variety of changes in the body beyond just altering blood sugar levels. Not all cancers are glucose driven. There is likely a larger grouping of cancers that are facilitated by excess energy in the body (glucose being one form of that), all of which might be helped by exercise. But exercise has many other downstream effects.
Rather than restricting carbs, an approach to requiring a bout of exercise before eating would be much more in line with evidence.
"...Intense aerobic exercise increases the glucose (sugar) consumption of internal organs, thereby reducing the availability of energy to the tumor."
Interestingly, this is a key part of the medical argument for low-carbohydrate diets--that most human diseases are metabolic ones, including cancer, and that modern human diets are at the root of them. One discussion: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6375425/
I’d go as far as to say that the burden of proof is on anybody claiming that exercise is not as fundamental as eating, sleeping or breathing. So this study seems obvious or at least reasonable to me.
The burden of proof is generally on the person standing up and making a claim, no matter how obvious the claim is or which side they're trying to prove.
But even when two people make opposite claims and there's no good consensus either way, trying to assign burden of proof by what seems obvious or reasonable isn't a solution. That just takes you back to two people disagreeing about what is obvious or reasonable, it's just going in circles.
Something you can do instead is put burden of proof on the person deviating from the null hypothesis, because everyone can agree on that. Crucially, the null hypothesis does *not* mean the obvious thing, or the expected thing.
In the case of whether breathing is fundamental and healthy, the null hypothesis is that breathing does absolutely nothing. And of course it's not very hard to reject that one, the null hypothesis is clearly wrong here. If it really is obvious, then you shouldn't have a hard time rejecting it and all is right in the world.
But trying to make a claim that's not so easy to prove, and at the same time trying to escape the burden of proof because it 'seems obvious or at least reasonable' harms your ability to notice when you're wrong. It's dangerous and it's bad epistemology.
Correct me if I'm wrong but you can state the null hypothesis arbitrarily: "Breathing does nothing" / "Not breathing does nothing." "Aerobic exercise does not increase the probability of developing metastatic cancer" / "A sedentary lifestyle does not increase the probability of developing metastatic cancer." So, in fact your null hypothesis already has a bias of what you consider the baseline, i.e. yes-cancer or no-cancer. So in essence, you are trying to scientize for the sake of argumentation.
>"Breathing does nothing" / "Not breathing does nothing."
Right, but that's because those two are actually the same! The null hypothesis in this case does not directly say whether breathing is good or bad, instead it's a statement about the correlation of breathing to anything at all.
If the null hypothesis is true, then breathing or not breathing doesn't have any effect. So the null hypothesis is not pro-breathing or anti-breathing, the null hypothesis is that it just doesn't matter either way and doesn't correlate with anything (like the person staying alive)
>"Aerobic exercise does not increase the probability of developing metastatic cancer" / "A sedentary lifestyle does not increase the probability of developing metastatic cancer."
With both of those, you can also reformulate them to be a statement about correlation. "What is the correlation between the amount of aerobic exercise that you do and the rate of development of metastatic cancer?"
So the null hypothesis doesn't depend on whether you think exercise is good or bad. That's the subtlety. It just says that everything is neutral and nothing has any effect until proven otherwise.
That doesn't mean the null hypothesis is always what makes sense, or that it's what you should believe in. Obviously breathing keeps you alive, and exercise has a lot of benefits. It's just a way to keep people from disagreeing about what's obvious and who should prove what. The null hypothesis is really dumb, and it only says that anyone who claims they found a real effect, either good or bad, should prove it.
If one person is saying red wine causes cancer, and the other person is saying red wine prevents cancer, then they're both rejecting the null hypothesis, which is that you can't claim red wine correlate with anything until proven otherwise.
And I promise this isn't just for the sake of the argument. There's a real difference between the mindset of trying to claim "X is good" or "X causes cancer" because it seems so obvious that someone else should just prove the opposite instead, and the much more boring idea that if something is actually kind of obvious, then you should be able to measure whether it does anything AT ALL in either direction (good or bad), and force the person actually making the claim to reject the null hypothesis.
As I understand it, correlation is not sufficient to prove causation. "Null hypothesis" is one statistical tool, an abstraction over our understanding of the real world.
Consider the case where all of those infected with disease D die, while 99% of those infected with D and treated with T survive. Further consider that T is widely administered. Clearly, the correlation between being infected and dying is very low although with a deeper understanding we know that D in fact causes death.
>As I understand it, correlation is not sufficient to prove causation. "Null hypothesis" is one statistical tool, an abstraction over our understanding of the real world.
Absolutely. The only reason we use it is because most of the other alternatives turned out to be not that great in practice, but it has plenty of limitations to keep in mind (like correlation != causation, but also the common p-hacking that happens, etc etc).
>Clearly, the correlation between being infected and dying is very low although with a deeper understanding we know that D in fact causes death.
That's true, although working back from just the people who die and focusing on those, the method is eventually able to unearth the correlation too. With the people who die, we would naturally start to ask why them? Did they do anything differently than the rest of the population? We'd see pretty quickly that there was one huge factor in common, which is that none of them were using T.
I'll admit that's not enough to say just looking at correlations and trying to disprove nulls is going to be enough in every case. I would just say it's a pretty good starting point when people disagree on a fundamental level about what should be obvious, or who should be proving what. It's really kind of dumb, but in practice in the case of people missing something (most deficiencies, like not having enough vitamin B12, or not having enough thyroid hormone) stats do a pretty good job of noticing that all the people dying mysteriously happen to be missing the same thing. (But of course it misses plenty of things too. And where it gets a lot harder is understanding why any of this happens)
I get mixed feelings whenever I see one of these reports. It's nice to get more data in the fight against cancer but it doesn't look like any progress in directly attacking cancer. And there's doubt about the data too. I wonder about how much money and effort is going into such studies which is not being invested into novel techniques for attacking cancer.
You could do cardiovascular exercise which, in theory, might possibly have a beneficial reduction in personal cancer rates (among many other potential health benefits attributed to persistent exercise). Or you could not do cardio.
I'm sure almost anything that increases cellular stress, including calorie restriction, exercise, sleep deprivation, and chemotherapy, are adept at killing cancer cells that should theoretically be slightly less fit than healthy cells.
Extremely weird take.
1) the paper refers to high intensity activity like sprinting which which many lifelong runners don't do.
2) your personal experience is a random sample which is probably not representative.
The paper suggests you need to be at 80-85% max effort to get maximum benefit, the runners I know tend to concentrate on distance and the social aspect (so are running at an effort where they can sustain a conversation), rather than getting to the end of the run as quickly as possible.
The summary says the human studies used 3000 people over twenty years and the 72 percent less compares the humans who did high intensity exercise versus those who did not - it did not state the rate was zero, it was just significantly less in those who did high intensity exercise.
anybody who lives long enough succumbs to cancer. anybody. not one exception. you can have the fittest heart and safest lifestyle, but your cells will always replicate with less and less accuracy, the sun and other sources of genetic damage will keep inundating you.
Yeah, I wouldn't be surprised if more runners do die from cancer. Because they're not falling victim to all the other things that are improved by cardio fitness, etc.
link to full paper: https://aacrjournals.org/cancerres/article/82/22/4164/710131...