> Analyses adjusted for age, sex, duration of light intensity physical activity, duration of moderate intensity physical activity, smoking history, alcohol consumption, accelerometer estimated sleep duration, fruit and vegetable consumption, education, self-reported parental history of cardiovascular disease and cancer, and self-reported medication use (cholesterol, blood pressure, and diabetes), and prevalent cancer and CVD.
We should be very nervous about any results that depend on this many adjustments. Remember: If their measure of smoking history is crude or inaccurate, this basically means they only "half control" for it.
What I would love to see in this kind of a study is what the strength of the association is WITHOUT adjusting for anything and then show how it changes as more adjustments are added. If the association drops a lot with each adjustment, then we should be suspicious that enough controls haven't been included or the controls are too noisy.
Of course, at the end of the day, nothing substitutes for an RCT. These kinds of observational studies are worth thinking about even though they are much less informative, given that they are orders of magnitude cheaper. It's just worrisome that most popular reporting doesn't seem to recognize how much less they should be trusted.
Nature Medicine is known in the field for sometimes publishing studies with dubious statistical methods.
It's a great journal in terms of metrics, but more often than not they publish things that look interesting but not very robust.
For example, most studies that do multivariate analyses (not applicable here) do not do partial pooling. Hence, they end up with inflated effect sizes.
Nature Genetics is also letting this happen all the time, which is annoying and leads to non-reproducible findings.
I'm not sure I agree with the level of adjustment being a negative here. The point they are making is that have adjusted for confounders ie. considered other covariates (all those listed) and the results still show their exposure (VILP) being associated with their outcome of interest (mortality). It's usually better to account/adjust for as many confounders as possible (happy to be corrected by someone on this!), especially those that are clinically relevant. Usually, more covariates in the model takes it towards the null so if there is still an effect estimate, it's likely to be a better association than using crude values.
My issue with these studies from the UK Biobank though is that the wearable devices are only worn for up to 2 weeks or so, although the follow period is significantly longer in this study. For this study the "participants were required to have at least three valid monitoring days, with at least one of those days being a weekend day". Would be better to have a prospective cohort but good to see associations so further studies can investigate.
Yes, someone who is unable to climb the stairs might not be long for this world but...making them sprint up a staircase is unlikely to prolong (rather than shorten) their lives.
> Yes, someone who is unable to climb the stairs might not be long for this world but...making them sprint up a staircase is unlikely to prolong (rather than shorten) their lives.
The direction of causation could be reversed too. It might be that inactivity is a sign of deteriorating biological systems.
At first, this paper seemed to me to be contradictory: having defined VILPA as excluding exercise for the purpose of exercising, it recommends doing it for that purpose... On reflection, I think the advice is directed towards people who could take the stairs, but habitually don't. Aside from that and running to the next bus/train stop, I'm not sure there are all that many options for this sort of behavior modification without setting aside some time for it.
>I think the advice is directed towards people who could take the stairs, but habitually don't.
I think we could probably agree with this advice based on strong priors but this paper provides poor support for the advice since it's not an intervention, it's an observation of extreme sedentary "lifestyles" which are probably heavily skewed towards various forms of illness (or infirmity from old age).
I think that's kind of baked into the definition of VILPA. that is to say, it is by definition intermittent. Some people have Lifestyles with more of it and some have less of it. If you take the paper at face value, it is better to live a lifestyle with it
I don't know what to say other than — you are wrong. It's extremely rare for someone without an actual heart defect to die because they exercised too hard.
Disrupting a long sedentary and poor diet lifestyle with abrupt vigorous physical activity is known to risk breaking loose chunks of vascular plaque.
Those can then cause a stroke when they obstruct blood flow to something critical. The stroke may be fatal, or maybe you just loose capabilities like motor control of half your body.
Either way, there's a reason many people are advised to consult with their physician before beginning an exercise regimen.
Also, I can't help wondering whether this study's results are applicable to what they call a "stress test" at your doctor's. Or is that beyond the regime they were examining.
> VILPA refers to brief and sporadic (for example, up to 1 or up to 2 min long) bouts of vigorous-intensity physical activity done as part of daily living, such as bursts of very fast walking while commuting to work or moving from place to place, or stair climbing.
Seems like a really low bar for someone without disabilities. Doesn't this association read too much into it?
I mean if someone is so physically disconditioned that this level of activity is not the case (excluding disability) then yeah that kind of sedentarism seems like a recipe for CVD.
maybe they failed to adequately control for alternative causal graphs
maybe people with atrial fibrillation make up a disproportionate fraction of the lower-vilpa groups, for example, because walking up stairs fast leaves them lightheaded, so they walk up stairs slowly instead, and later the fibrillation kills them at high rates
doesn't mean walking up the stairs fast would be good for you if you have afib
I think this study is examining the elderly, nonexerciser population so they are seeing if VILPA could be some sort of substitute for not dedicating time to exercise.
I think mortality is not a good motivator for exercise. I exercise a lot but mainly for the benefits it gives me now. I feel stronger and clearer. I don’t really care about extending my life as long as I feel good while I am alive. Even if exercise shortened my life somewhat I would still do it because life until I am dying will be better.
You would think people would know this by now, but I guess these sorts of studies are seeing if "lowering the standards" for exercise still has enough of a beneficial effect. If we could get away with it, I think most of us would eat delicious foods and not exercise. I really wish we could have "exercise in a pill".
I think this drum still needs to be banged, either more often or in a different way.
This might sound ridiculous, but some people even equate calls for exercise with fat-shaming. I've seen complaints like that posted in internal FAANG newsgroups as a response to events encouraging people to do exercise.
This new research tells us that you actually don’t need to properly exercise, using up a lot of your time to see a positive effect on mortality rates. A few short activity bursts will do. Chances are that more people will be willing to fit this into their daily routine. Wearable devices can gamify this for you.
And it may act as a motivator. How many people end up being literally petrified by the prospect of having to spend a few hours exercising every week? And rather not exercise at all.
On the bottom line, it may help improve the health of a cohort that does not currently exercise at all.
I think they are more to determine a set of specific guidelines that make it easier to recommend to people.
Saying, "Eat good food and exercise more" is very general, whereas "Get 10 minutes of intense exercise per day" or something like that is more measurable and actionable, especially with the use of wearables...
".. sample median VILPA frequency of 3 length-standardized bouts per day (lasting 1 or 2 min each) " vigorous intermitant lifestyle physical activity ?
apparently this is a study regarding seniors and elderly, and instilling a habit of doing something "vigorous" for less than five minutes, a few times each day
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We should be very nervous about any results that depend on this many adjustments. Remember: If their measure of smoking history is crude or inaccurate, this basically means they only "half control" for it.
What I would love to see in this kind of a study is what the strength of the association is WITHOUT adjusting for anything and then show how it changes as more adjustments are added. If the association drops a lot with each adjustment, then we should be suspicious that enough controls haven't been included or the controls are too noisy.
Of course, at the end of the day, nothing substitutes for an RCT. These kinds of observational studies are worth thinking about even though they are much less informative, given that they are orders of magnitude cheaper. It's just worrisome that most popular reporting doesn't seem to recognize how much less they should be trusted.
It's a great journal in terms of metrics, but more often than not they publish things that look interesting but not very robust.
For example, most studies that do multivariate analyses (not applicable here) do not do partial pooling. Hence, they end up with inflated effect sizes.
Nature Genetics is also letting this happen all the time, which is annoying and leads to non-reproducible findings.
My issue with these studies from the UK Biobank though is that the wearable devices are only worn for up to 2 weeks or so, although the follow period is significantly longer in this study. For this study the "participants were required to have at least three valid monitoring days, with at least one of those days being a weekend day". Would be better to have a prospective cohort but good to see associations so further studies can investigate.
But you must realise that effects would be entirely obscured without corrections. That's just the central limit theorem.
But I think this thread misses the main thrust of the research.
Next time you read a paper about someone living longer for say. Combing their hair think, should they have corrected for VILPA?
Yes, someone who is unable to climb the stairs might not be long for this world but...making them sprint up a staircase is unlikely to prolong (rather than shorten) their lives.
The direction of causation could be reversed too. It might be that inactivity is a sign of deteriorating biological systems.
I think we could probably agree with this advice based on strong priors but this paper provides poor support for the advice since it's not an intervention, it's an observation of extreme sedentary "lifestyles" which are probably heavily skewed towards various forms of illness (or infirmity from old age).
Those can then cause a stroke when they obstruct blood flow to something critical. The stroke may be fatal, or maybe you just loose capabilities like motor control of half your body.
Either way, there's a reason many people are advised to consult with their physician before beginning an exercise regimen.
Stay active folks...
Also, I can't help wondering whether this study's results are applicable to what they call a "stress test" at your doctor's. Or is that beyond the regime they were examining.
> VILPA was inversely associated with all three of these outcomes in a near-linear fashion
I think the title (in the paper itself, and therefore also in the HN submission) is misleading. Title should be "...with lower mortality"
Seems like a really low bar for someone without disabilities. Doesn't this association read too much into it?
I mean if someone is so physically disconditioned that this level of activity is not the case (excluding disability) then yeah that kind of sedentarism seems like a recipe for CVD.
maybe people with atrial fibrillation make up a disproportionate fraction of the lower-vilpa groups, for example, because walking up stairs fast leaves them lightheaded, so they walk up stairs slowly instead, and later the fibrillation kills them at high rates
doesn't mean walking up the stairs fast would be good for you if you have afib
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Deleted Comment
This might sound ridiculous, but some people even equate calls for exercise with fat-shaming. I've seen complaints like that posted in internal FAANG newsgroups as a response to events encouraging people to do exercise.
Dead Comment
And it may act as a motivator. How many people end up being literally petrified by the prospect of having to spend a few hours exercising every week? And rather not exercise at all.
On the bottom line, it may help improve the health of a cohort that does not currently exercise at all.
Saying, "Eat good food and exercise more" is very general, whereas "Get 10 minutes of intense exercise per day" or something like that is more measurable and actionable, especially with the use of wearables...
".. sample median VILPA frequency of 3 length-standardized bouts per day (lasting 1 or 2 min each) " vigorous intermitant lifestyle physical activity ?
apparently this is a study regarding seniors and elderly, and instilling a habit of doing something "vigorous" for less than five minutes, a few times each day