Turns out, its 2.5 times your base metabolic rate, for a "all the time" limit.
an interesting article slightly spoiled by reference to "for an average person" which frankly could mean anything
an interesting article slightly spoiled by reference to “for an average person” which frankly could mean anything
From the article:
They showed the cap was 2.5 times the body's resting metabolic rate, or 4,000 calories a day for an average person.
I read that as 2.5 times the average person's resting metabolic rate is 4000 calories. So the average resting MR is 1600 calories.
that's what I understood from it too
Quite possible that BMR is 1600Kcal/day with the 900 difference from the recommended daily intake of 2500Kcal for men being taken up by everyday activities.
Quite possible that BMR is 1600Kcal/day with the 900 difference from the recommended daily intake of 2500Kcal for men being taken up by everyday activities.
Thats how I read. Base metablic rate in this context is how much energy your body uses just to live before execise ie breathing, digesting food, thinking about beer.
I knew a bloke who had mates who did deca iron man races. They would say that you can only get so tired.
In case you haven't heard of it, deca iron man is ten iron mans all in one go. That's 24 mile swim (in a ****ing pool!), 1120 mile bike ride and 262 mile run. I think they use more than 4,000 calories a day doing that.
And if you read the article, you can exceed this in the short term and run a deficit, but long term there is a limit to how many calories the body can absorb
"You can do really intense stuff for a couple of days, but if you want to last longer then you have to dial it back," Dr Herman Pontzer, from Duke University, told BBC News.
Just googled it... one DecaUK bike leg seems to be a 10 mile loop and the running loop is just over a mile. I suspect not dying of boredom would be the most difficult part 😂In case you haven’t heard of it, deca iron man is ten iron mans all in one go. That’s 24 mile swim (in a **** pool!), 1120 mile bike ride and 262 mile run.
What I'd like to see, might have missed it, is what power output is sustainable indefinitely. The human body is around 25% efficient so 4000KCal as input is roughly equal to 4000 KJoules of output so that's 4 million Watt/seconds. Let's say you are on the move for 18hrs that's 18 * 60 * 60 seconds = 64800 seconds.
4,000,000/64800 = 61.7W
I used 3W/kg in British Cycling's Power zone calculator and Zone 1 (Active recovery) is anything below 125W so it's a very easy pace.
I think I've got all that right. Feel free to correct me.
one DecaUK bike leg seems to be a 10 mile loop and the running loop is just over a mile. I suspect not dying of boredom would be the most difficult part
The one I was told about had a 1.6 mile biking loop on a closed flat racing circuit. To **** with you even more it was the same loop you ran on.
What I’d like to see, might have missed it, is what power output is sustainable indefinitely.
Well there are plenty of races where people do nothing but ride and sleep. They are on more than 60W. Or do you mean without sleeping?
@molgrips - no, I was just considering what 18hrs "effort" would require, the other six hours would be rest/sleep so I suppose I should have removed a quarter of the available energy input to account for the BMR for that period.
Remember this is for "indefinite" activity so what would be more practical for most is what energy/power can you output for three, five, seven, twenty days. By necessity you'll be drawing on your body's reserves for these higher levels so going in to such an event might actually require gaining a bit of weight in anticipation.
Another way of looking at it is that you've a maximum sustainable four million Watt-seconds available per day, how you use it is up to you.
I reckon for a 20 day effort you're already in energy equilibrium. Your biggest issue is mental and wear and tear.
I don't know what his average was over the whole 24hrs but this is the first lap of the 2017 24hr World Champs with power and heart rate (when he gets to the bike), presumably pacing himself, although the first lap tends to be a bit quicker. He's good though, seven wins, one second and one fifth in the last nine years.
That's muggins here in the XCRacer kit, I can beat the big names on foot, just got to work on the riding now...
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I've taken part in medical studies looking at endurance athletes and one of the things they've found is that trained athletes are far more efficient than 'average' people at burning energy, so their metabolic rate isn't at high i.e. extrapolating data for 'average' becomes pretty meaningless.
From my own experience at doing 5-day endurance races in the arctic in winter, it simply wasn't possible to consume my suggested calorific intake so food intake wasn't the limiting factor as psychology and the continual muscle pain, fatigue and niggly injuries really start to take their toll.
They looked at trained athletes in this study not average people, the article made specific reference to running race across America.
2.5x metabolic base rate was the ceiling that everyone trended towards, the longer an event went on.
presumably, the fact that they were studying people over such long events meant that towards the end of the events, the period they were most interested in., the more mentally and physically fragile competitors were excluded themselves, and the study began to focus purely on the metabolic/effort/endurance relationship.
The study looked at Tour de France riders and Artic explorers and the like. It's specifically about what you can do for long periods, not short events.
In case you haven’t heard of it, deca iron man is ten iron mans all in one go. That’s 24 mile swim (in a **** pool!), 1120 mile bike ride and 262 mile run.
There are 2 variations for the Deca, the Continuous, which is as you describe, and the 1=a=Day, which is a standard Iron-distance tri per day for 10 days. Both have their own difficulties. For the continuous, it's that solid, large block of swimming (usually in a pool, as for safety reasons it's a nightmare to do it in open water), followed by a large block of cycling and then a large block of running with no respite from that activity until it's finished. You do however get to dictate your own rest schedule. With the 1-a-day, the issue is recovery time, or lack thereof. As you get slower over the course of the event, you get less time to recover before the next day kicks off.
As for the courses, Decas (and beyond, there are Double and Triple Decas) are almost always on short loops. This is for a number of reasons, primarily safety as it allows the event team to keep a continual eye on competitors and monitor what sort of state they're in. From a competitor point of view, whilst you may initially suffer with boredom, as the event progresses you need the course to be as simple and straightforward as possible. The previous DecaUK in 2018 was held at Dorney and the bike course was around 3.3 miles as a simple out-and-back.
Matt (part of the DecaUK crew)
https://en.m.wikipedia.org/wiki/Pedestrianism
1000 miles in 1000 hours was honoured target.
For my 12 hrs I average 200 watts or 3 watts/kg. That’s not sustainable indefinitely. But average that with good rest and I can easily believe 100 watts would be.
From my own experience at doing 5-day endurance races in the arctic in winter, it simply wasn’t possible to consume my suggested calorific intake so food intake wasn’t the limiting factor as psychology and the continual muscle pain, fatigue and niggly injuries really start to take their toll.
Yes, and that's what I heard about the Decas. The real issue is the state of your arse during all that riding and your feet for the running.