Running/Cycling Thread - 2015 Edition - Page 6

On February 04 2015 07:46 JinDesu wrote:
http://www.acc.org/latest-in-cardiology/journal-scans/2015/02/02/15/13/dose-of-jogging-and-long-term-mortality?w_nav=LC

Anyone able to get into this article (the login process seems to take more information than I have) and review? Quite a lotta people are now putting the New Yorker (http://nymag.com/thecut/2015/02/cool-news-jogging-too-much-is-bad-for-you.html?mid=facebook_nymag) and BBC links on social media and I want to read the source because I suspect something is being mistranslated by the new orgs.

Nevermins, doc friend of mine was able to download it as a PDF for me, will look at it tonight.

Again, however, maximal CV longevity benefits were noted with moderate doses of running (specifically 6 to 12 miles per week), running durations of approximately 50 to 120 min per week, a running frequency of approximately 3 times per week, and a modest pace of approximately 6 to 7 miles per hour. Our findings are aligned in that a U-shaped or reverse J-shaped relationship was noted, whereas higher doses of running were associated with loss of approximately one-third to one-half of the CV mortality benefits linked to moderate doses of running. In fact, the most favorable running regimen for reducing CV mortality in that study was 6 miles per week, 3 running days per week, and a pace of 7 miles per hour.

even slow jogging (6 METs) corresponds to vigorous exercise

strenuous jogging (8:30 pace) corresponds to very heavy vigorous exercise (≥12 METs)

On February 04 2015 14:18 JinDesu wrote:
From the abstract:

BACKGROUND People who are physically active have at least a 30% lower risk of death during follow-up compared
with those who are inactive. However, the ideal dose of exercise for improving longevity is uncertain.

OBJECTIVES The aim of this study was to investigate the association between jogging and long-term, all-cause
mortality by focusing specifically on the effects of pace, quantity, and frequency of jogging.

METHODS As part of the Copenhagen City Heart Study, 1,098 healthy joggers and 3,950 healthy nonjoggers have been
prospectively followed up since 2001. Cox proportional hazards regression analysis was performed with age as the underlying time scale and delayed entry.

RESULTS Compared with sedentary nonjoggers, 1 to 2.4 h of jogging per week was associated with the lowest mortality
(multivariable hazard ratio [HR]: 0.29; 95% confidence interval [CI]: 0.11 to 0.80). The optimal frequency of jogging was
2 to 3 times per week (HR: 0.32; 95% CI: 0.15 to 0.69) or #1 time per week (HR: 0.29; 95% CI: 0.12 to 0.72). The optimal
pace was slow (HR: 0.51; 95% CI: 0.24 to 1.10) or average (HR: 0.38; 95% CI: 0.22 to 0.66). The joggers were divided
into light, moderate, and strenuous joggers. The lowest HR for mortality was found in light joggers (HR: 0.22; 95%
CI: 0.10 to 0.47), followed by moderate joggers (HR: 0.66; 95% CI: 0.32 to 1.38) and strenuous joggers (HR: 1.97; 95%
CI: 0.48 to 8.14).

CONCLUSIONS The findings suggest a U-shaped association between all-cause mortality and dose of jogging as
calibrated by pace, quantity, and frequency of jogging. Light and moderate joggers have lower mortality than sedentary
nonjoggers, whereas strenuous joggers have a mortality rate not statistically different from that of the sedentary
group. (J Am Coll Cardiol 2015;65:411–9) © 2015 by the American College of Cardiology Foundation.

I don't want to post up the PDF since my friend had to log in to download it, but I'll read through and provide my thoughts..

My thoughts below (disclaimer, I'm a layman):

The study assumes a light pace equals 6 metabolic equivalents (METs) given a frequency of less than 2.5 hours of jogging a week divided by 3 times a week. A moderate pace is rated at greater than 2.5 hours of jogging a week divided by 3 times a week (or a fast pace less than 4 hours a week divided by 3 times a week). A strenuous pace is rated at more than 12 METs, given more than 4 hours a week divided by 3 times a week.

Per Wiki and the web, 6 METs is jogging in general (10 minute miles) while 12 METs is approximately 8 minute miles. I don't know how accurate this is, but it's what I find on the web.

The study states that, for a nonjogger reference (1.00HR) and adjusted for age, sex, smoking, alcohol intake, education, and diabetes, a jogger running less than 1hr a week has a HR of 0.47. A jogger running 1-2.4hrs/week has a HR of 0.29. A jogger running 2.5-4hrs a week has a HR of 0.65. A jogger running more than 4 hours a week has a HR of 0.6.

For a nonjogger reference of (1.00HR), adjusted for the same factors above, a jogger who runs 1 time a week has a HR of 0.29. A jogger who runs 2-3 times a week has a HR of 0.32. A jogger who runs more than 3 times a week has a HR of 0.71.

For a nonjogger reference of 1.00HR, adjusted from the same factors above, a jogger who runs at a low space has a HR of 0.51. A jogger who runs at a moderate pace has a HR of 0.38. A jogger who runs at a strenuous pace has a HR of 0.94.

I don't know how these numbers combine given something like a jogger running 2.4hrs a week, once a week, at a moderate pace, but it seems that those exact factors provided the lowest mortality rate/hazard ratio. The paper makes a statement that a METs of 12 at an extended duration for a long period of time can pose risks to the cardiovascular system due to the high intensity of exercise. In all cases, jogging is better than being sedentary - but the paper makes the statement that vigorous jogging comes close to having the same hazard ratio as being sedentary.

The hazard ratio is a reference to deaths caused by respiratory diseases, stroke, and cancer (with the adjustments made for age, sex, smoking, etc). The paper mentions that past studies have found a similar U shape curve when accounting for energy expenditure/exercise intensity with respect to mortality rates. A reference study (by Paffenbarger et al) stated that a physical activity increase from 500-3500kcal (over resting rate) per week is the optimal range of optimizing long-term cardiovascular health and life expectancy - and anything above or below that would increase the mortality rate. The study also makes the statement that high intensity regimens can improve peak cardiac performance and cardiorespiratory fitness, it may not be ideal for promoting long term CV health and overall life expectancy.

I'm not sure how the HR rate works - if someone with a better understanding can help explain it, that'd be great. My assumption at this time is that if the control is HR=1.00 and the result is a HR=0.30, that means that for 10 people who die under the control group, only 3 people will die under the result group. If that's wrong, let me know.

I myself think that I'm a moderate runner. Before winter I was doing 2-3 runs a week, about 4-8 miles per run, at a pace of about 9-10 minute/mile (totaling an average of 2.4hrs of running a week). I was planning to maintain that for this year as an enthusiast jogger.

1 to 2.4 h of jogging per week was associated with the lowest mortality
(multivariable hazard ratio [HR]: 0.29; 95% confidence interval [CI]: 0.11 to 0.80). The optimal frequency of jogging was
2 to 3 times per week (HR: 0.32; 95% CI: 0.15 to 0.69) or #1 time per week (HR: 0.29; 95% CI: 0.12 to 0.72). The optimal
pace was slow (HR: 0.51; 95% CI: 0.24 to 1.10) or average (HR: 0.38; 95% CI: 0.22 to 0.66). The joggers were divided
into light, moderate, and strenuous joggers. The lowest HR for mortality was found in light joggers (HR: 0.22; 95%
CI: 0.10 to 0.47), followed by moderate joggers (HR: 0.66; 95% CI: 0.32 to 1.38) and strenuous joggers (HR: 1.97; 95%
CI: 0.48 to 8.14).

On February 05 2015 15:14 JinDesu wrote:
YPang, thank you for your insight. I didn't know what confidence intervals meant, but I'll go look them up now. I suppose you do bring up a good point, don't jog behind heavy polluting vehicles

On February 05 2015 19:44 YPang wrote:

yeah the confidence interval range is pretty much stating what the hazard ratio COULD potentially be. So when the confidence interval is something like "0.22-1.45" it means that it can literally range anywhere in between there since it crosses 1 and has the chance of being just as good as the control group. Often times when you get a insignificant data, a small sample size is usually to blame because the researcher's aren't sure, and there are always outliers.

Again, without looking more into the methods to find for potential bias, Since the moderate, and streanous exercise's group both crossed 1 for the confidence interval.

On February 06 2015 13:04 L_Master wrote:


Well in fairness (though you probably know all of this since it seems you have some background in epidemiological studys/methods) it doesn't technically prove that. It just says with confidence that people that engage in light jogging / average speed live longer than sedentary people. But there are other potential confounders that could explain the reason (i.e. people that do light running are more likely to eat better, visit the doctor more, sleep more, etc. )

On February 14 2015 15:43 Bonham wrote:
I'm running the Vancouver half marathon on May 3rd. There's a 100 mile relay team race in Alberta in June that my training group enters two teams for. To make our A team, I'd have to run Vancouver in 1:11 or 1:12. My coach thinks I can do this, but I'm sceptical. My 1:13 from August came as a tuneup for a full marathon six weeks later. I was running pretty high mileage then and had a better base to my training than I do now.

On the other hand, I've got three and a half months to get ready, the traction outside will get better in late March, and I've got this new group to train with.

L_Master (or anyone else who knows my training a bit and knows running): is it realistic to think about 1:11 in May? I did the math on the pace during a quiet moment at work this afternoon and got kind of wigged out. Advise me!

On February 14 2015 15:43 Bonham wrote:
Go Don_Julio go! Any race after a recovery from injury is a good one.

I'm running the Vancouver half marathon on May 3rd. There's a 100 mile relay team race in Alberta in June that my training group enters two teams for. To make our A team, I'd have to run Vancouver in 1:11 or 1:12. My coach thinks I can do this, but I'm sceptical. My 1:13 from August came as a tuneup for a full marathon six weeks later. I was running pretty high mileage then and had a better base to my training than I do now.

On the other hand, I've got three and a half months to get ready, the traction outside will get better in late March, and I've got this new group to train with.

L_Master (or anyone else who knows my training a bit and knows running): is it realistic to think about 1:11 in May? I did the math on the pace during a quiet moment at work this afternoon and got kind of wigged out. Advise me!

On February 17 2015 08:48 mtmentat wrote:

Who are these fast people you are training with these days? Will some of your potential A-list peers be running Vancouver with you, so you can work with/key off of them?