chinarider

This is actually quite a bit:

https://www.yahoo.com/news/much-exer...85.html?ref=gs

Machka 

Can you give us a brief summary of what's in the link?

deapee

"The daily dose of physical exertion required to lower the risk of diabetes, stroke, heart disease, and both breast and bowel cancer by at least 20 percent, is several times the mininum recommended by the World Health Organization, researchers found (AFP Photo/Kirill Kudryavtsev)"

It's a really short article though.

gregf83 

They reviewed thousands of studies and concluded that the WHO's recommended 600 MET minutes per week didn't lower disease or cancer risk significantly. They found 3500 to 4000 MET minutes/week from combined activities provided the most benefit.

1 MET => resting, 4 METs => moderate exercise, 8 METs =>higher intensity like running.

chinarider

They say the necessary level to get these benefits is 3,000 to 4,000 METS per week. They say 10 minutes of running = 80 mets, so (if that's accurate) you'd have to run 8.3 hours a week to get to 4,000 METS. For comparison, at the level recommended by the WHO -- 600 MET minutes -- there was hardly any impact at all, according to the study.

I'd say you'd have to at least double the time running to get an equivalent for biking, so it would come out to over 2 hours a day. These are obviously rough approximations, but however you cut it, it's a lot more than the paltry levels of exercise many mainstream media articles talk about.

DrIsotope

This whole MET thing just excites me. Head over to the Compendium of Physical Activites (Bicycling) to find your MET, multiply it by your time ridden per week, and smile or frown as needed.

Myself, for instance, look at it this way:

A 10.0 MET is "bicycling, 14-15.9 mph, racing or leisure, fast, vigorous effort", and
a 12.0 MET is "bicycling, 16-19 mph, racing/not drafting or > 19 mph drafting, very fast, racing general"

I don't race, but I do average 17-18mph over the course of a week (+10,000kj per week) so I'll call myself an 11.0 MET.

8/1 - 8/7, 924 minutes * 11.0 MET = 10,164 MET

Seattle Forrest

I think everybody has known for a while that the official recommendations aren't enough. There have been a lot of studies lately on the dangers of a sedentary lifestyle, I saw an article last year in Runners World about how even runners are usually too sedentary, it said don't think that doing some exercise makes it ok to spend the rest of the day sitting.

But it's like pulling teeth to get a lot of people to park on the far side of the lot and walk a little extra. The official recommendation for 150 minutes per week (that's 2.5 hours) is probably about setting the bar low enough that people will do it.

Seattle Forrest

I guess that's across the population as a whole.


There's no history of diabetes in my family. There's a genetic component so already I'm not at much risk. Exercise improves your sensitivity to insulin (which is basically the opposite of type 2 diabetes), so with the cycling I do, it's just not on the radar.


I have no idea what number of METs I come to, and I doubt it's 4 to 6 k, but that's like asking somebody to walk some number of leagues when they're used to miles, METs means nothing to me, I have no context. (And I'm a bit skeptical.) But whatever number I come to, my risk level for T2D is acceptable.


Men can get breast cancer (the guy who played Shaft did) but I have no idea how to go about assessing risk for that. Ovarian cancer did my grandmother in, and I think that's a risk factor for BC, but I don't have ovaries.

chinarider

Doesn't really have consistency. For example, says biking 10-16 mph is 6.8 -10 METS (I assume this is per minute; it doesn't really say), but running 5-8 mph is 8.3-11.8 METS. I would think the differential between running and biking would be much greater. Even using their MET level for biking (which seems way to high), one would have to bike about an hour a day at ~15 mph to reach the desired MET level. I think double that to reach 4000 METs a week is more realistic.

DrIsotope

Well, it seems like the whole "MET" thing is just another way to go about guessing kilojoules, and I should have gone for the full 12.0, because according to the PM, I put out 11,592kj for that week, so the 10,162 MET would be way low, unless a MET is bigger than a kJ. I think it's useful, because it gives people who don't have other means to track their energy expenditure at least a general figure to help plan their intake.

The average person needs to exercise more. I think everyone knows this. But I average 2 hours of riding a day at ~17mph, so I have no problem almost tripling the recommended METs.

sprince

The MET thing is just another calories in calories out theory. It doesn't take into account what else you are and are not doing for most of the time, only measuring a single factor during a limited period of time and ignoring all others. Let's say that I drink vodka, smoke Chesterfields and inject heroin between my toes for an average of 10 hours a day. How much then does it matter that I did 4,000 MET's every week? Could be a little, none, or it might even increase my risk of death.

chinarider

I don't think there is any direct correlation between KJ and METs. I think METs is just an arbirary scale developed to try to quantify the amount of exercise one is getting. By its very nature, it's imprecise. You have a much more precise measure with your PM. And I agree, with the amount and quality of the cycling you do, I don't think you have to worry about reaching the recommended level.

My point in starting the thread was to point out that to get the benefits measured, the study seems to call for quite a bit more exercise than what is typically seen is mass media, where you typically see something like the 150 minutes per week prescription with the pronouncement that there is no real benefit in doing more than that.

Seattle Forrest

You misunderstand. The study is talking about lowering your risk of five specific diseases. Shooting heroin between your toes is bad for you, but it won't give you breast cancer.

Jseis 

I'd estimate 60-90 minutes of good hard cycling per day (8-11 MET) or 7-12 hours a week to hit 4000 MET. I'm at ~2000 in winter, maybe near 4000 in summer.

chinarider

My mistake. From the link above: "Definition of Terms used in the Compendium
MET (Metabolic Equivalent): The ratio of the work metabolic rate to the resting metabolic rate. One MET is defined as 1 kcal/kg/hour and is roughly equivalent to the energy cost of sitting quietly. A MET also is defined as oxygen uptake in ml/kg/min with one MET equal to the oxygen cost of sitting quietly, equivalent to 3.5 ml/kg/min."

1 kcal= 4.184 kJ. So if DrIsotope puts out 11,592kj, that would be 2770 kcal. If we knew his weight, we could compute the METs (if I'm understanding this).

caloso

Yes, but the human body is only about 25% efficient in converting heat energy to mechanical energy at the pedals. Which means that you can use kj measured at the pedals as equivalent to the energy cost (kcal).

sprince

Heavy drinking certainly raises the risk of breast cancer. Type 2 diabetes maybe should not be on list at all since it is entirely a consequence of diet first and exercise secondly. But those five specific diseases are major players in longevity. My point is that this "magic" number attempts to equate a met's per week to risk, while it ignores more important factors. If you look at the places where people live the longest, and thus have lower instances of these killer diseases, it is not calories burned, but diet quality and activity frequency. Activity frequency as in how many minutes during a day that you are active, being entirely different than met's per week which reveals nothing about what you do most of the time.

FXjohn

or people could eat less.

chinarider

I think studies like this are based on an "all other things being equal" assumption. That's why they use control groups. It is testing for the effect of exercise, not the other factors you refer to. No one is claiming the other factors aren't important.