Efficiency of the human body

[ewenm]

eddie1980 said:

Chris71 said:

eddie1980 said:

Chris71 said:

kambites said:

According to wikipedia:

The efficiency of human muscle has been measured (in the context of rowing and cycling) at 14% to 27%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost.[citation needed]

So an IC engine is better?

Government! We need to ban human beings...

Always wondered if cycling everywhere and the carbon costs of the increased food production would be worse then just using a car.

I am told the greener current cars put out less CO2 than joggers...

Never done the sums myself though.

That would be awsum if true, anyone got the maths on that?!

I'd be interested to see if they include the CO2 output of the driver in that too...

[Dr John]

CC07 PEU said:

Wouldn't you know accurately how many calories you burned if you were using a heart rate monitor linked up to the cardiovascular machine?

No
But you could measure energy consumption by measuring CO2 production and O2 utilisation.

John

Edited by Dr John on Tuesday 24th March 16:04

[eddie1980]

ewenm said:

eddie1980 said:

Chris71 said:

eddie1980 said:

Chris71 said:

kambites said:

According to wikipedia:

The efficiency of human muscle has been measured (in the context of rowing and cycling) at 14% to 27%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost.[citation needed]

So an IC engine is better?

Government! We need to ban human beings...

Always wondered if cycling everywhere and the carbon costs of the increased food production would be worse then just using a car.

I am told the greener current cars put out less CO2 than joggers...

Never done the sums myself though.

That would be awsum if true, anyone got the maths on that?!

I'd be interested to see if they include the CO2 output of the driver in that too...

http://www.dontjogdrive.com/Dont_Jog_Drive/Home.html

[ewenm]

eddie1980 said:

http://www.dontjogdrive.com/Dont_Jog_Drive/Home.ht...

What a great consequence of the government's focus on CO2!


Edit: And the "average" jogger does not do 4min/km - that's 2:49 pace for the marathon and much quicker than most joggers.

Edited by ewenm on Tuesday 24th March 16:15

[pacey_sot]

ewenm said:

eddie1980 said:

Chris71 said:

eddie1980 said:

Chris71 said:

kambites said:

According to wikipedia:

The efficiency of human muscle has been measured (in the context of rowing and cycling) at 14% to 27%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost.[citation needed]

So an IC engine is better?

Government! We need to ban human beings...

Always wondered if cycling everywhere and the carbon costs of the increased food production would be worse then just using a car.

I am told the greener current cars put out less CO2 than joggers...

Never done the sums myself though.

That would be awsum if true, anyone got the maths on that?!

I'd be interested to see if they include the CO2 output of the driver in that too...

And fuel production and transportation, and road repair equipment, and car production emissions, etc. etc. but still it'd be interesting

[Fuzzy Wuzzy]

The jiffle king said:

8Ace said:

kambites said:

According to wikipedia:

The efficiency of human muscle has been measured (in the context of rowing and cycling) at 14% to 27%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost.[citation needed]

Interesting. So even if I'm super efficient (27%), then 300 cals work requires over 1100 calories to produce.

Nice one, I'm off for a Creme egg.

Do the machines measure energy out, or do they adjust for energy in as well?

I guess that the machine has already taken this into account. When running, you can look at 100 calories per mile. My guess is that this would take the average person about 30 mins, so 300 calories. X trainer will be different, but you cannot burn 1100 calories in 30 mins

Oh yes you can, set yourself alight!

[eddie1980]

pacey_sot said:

ewenm said:

eddie1980 said:

Chris71 said:

eddie1980 said:

Chris71 said:

kambites said:

According to wikipedia:

The efficiency of human muscle has been measured (in the context of rowing and cycling) at 14% to 27%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost.[citation needed]

So an IC engine is better?

Government! We need to ban human beings...

Always wondered if cycling everywhere and the carbon costs of the increased food production would be worse then just using a car.

I am told the greener current cars put out less CO2 than joggers...

Never done the sums myself though.

That would be awsum if true, anyone got the maths on that?!

I'd be interested to see if they include the CO2 output of the driver in that too...

And fuel production and transportation, and road repair equipment, and car production emissions, etc. etc. but still it'd be interesting

Yes but that would be like including carbon cost of shoe manufacture for walking, and NHS carbon costs for hip replacements, and a million other things.

http://www.dontjogdrive.com/Dont_Jog_Drive/Home.ht...

Edited by eddie1980 on Tuesday 24th March 16:15

[ewenm]

eddie1980 said:

pacey_sot said:

ewenm said:

eddie1980 said:

Chris71 said:

eddie1980 said:

Chris71 said:

kambites said:

According to wikipedia:

The efficiency of human muscle has been measured (in the context of rowing and cycling) at 14% to 27%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost.[citation needed]

So an IC engine is better?

Government! We need to ban human beings...

Always wondered if cycling everywhere and the carbon costs of the increased food production would be worse then just using a car.

I am told the greener current cars put out less CO2 than joggers...

Never done the sums myself though.

That would be awsum if true, anyone got the maths on that?!

I'd be interested to see if they include the CO2 output of the driver in that too...

And fuel production and transportation, and road repair equipment, and car production emissions, etc. etc. but still it'd be interesting

Yes but that would be like including carbon cost of shoe manufacture for walking, and NHS carbon costs for hip replacements, and a million other things.

http://www.dontjogdrive.com/Dont_Jog_Drive/Home.ht...

Edited by eddie1980 on Tuesday 24th March 16:15

Reduced NHS costs of being fitter?

It's a facetious argument all round. I would be surprised if anyone out running would be doing so primarily because they think it's "greener" than driving.

[eddie1980]

ewenm said:

eddie1980 said:

pacey_sot said:

ewenm said:

eddie1980 said:

Chris71 said:

eddie1980 said:

Chris71 said:

kambites said:

According to wikipedia:

The efficiency of human muscle has been measured (in the context of rowing and cycling) at 14% to 27%. The efficiency is defined as the ratio of mechanical work output to the total metabolic cost.[citation needed]

So an IC engine is better?

Government! We need to ban human beings...

Always wondered if cycling everywhere and the carbon costs of the increased food production would be worse then just using a car.

I am told the greener current cars put out less CO2 than joggers...

Never done the sums myself though.

That would be awsum if true, anyone got the maths on that?!

I'd be interested to see if they include the CO2 output of the driver in that too...

And fuel production and transportation, and road repair equipment, and car production emissions, etc. etc. but still it'd be interesting

Yes but that would be like including carbon cost of shoe manufacture for walking, and NHS carbon costs for hip replacements, and a million other things.

http://www.dontjogdrive.com/Dont_Jog_Drive/Home.ht...

Edited by eddie1980 on Tuesday 24th March 16:15

Reduced NHS costs of being fitter?

It's a facetious argument all round. I would be surprised if anyone out running would be doing so primarily because they think it's "greener" than driving.

I agree, this is part of the issue, weighing up all the causes and effects is nearly impossible due to the complex integrated interdependent nature of our advanced society.

[ewenm]

eddie1980 said:

I agree, this is part of the issue, weighing up all the causes and effects is nearly impossible due to the complex integrated interdependent nature of our advanced society.

Not nearly impossible, entirely impossible. We can't even predict now from the info we had yesterday, we just don't know enough.

Anyway, don't go promoting ideas that runners produce more CO2 than cars or this government will want to tax me for the 100 miles I run each week!

[paulrockliffe]

Ewenm, fancy seeing you here!

[ewenm]

paulrockliffe said:

Ewenm, fancy seeing you here!

Can't get onto 8-lane from work so I waste time here chatting about my other passion. NO! Not that one! Cars!

[paulrockliffe]

I enjoyed reading that website, the most telling bit was, "We're not scientist and don't really know what we're talking about, but we're right until someone that does says we're wrong." or something like that.

They might have a point, I really don't know, but their presentation of a conclusion based on their interpretation of some facts that appear annecdotal and unsubstantiated is fairly weak. I noted that they say an average jogger does 4 mins per km, but also that an average jogger does 6.5 mins per km and wondered how many of their other facts were poorly put together. I won't get into all the other factors that they've not accounted for, such as the oversimplification of human metabolism and car CO2 stats.

[Jasandjules]

paulrockliffe said:

I enjoyed reading that website, the most telling bit was, "We're not scientist and don't really know what we're talking about, but we're right until someone that does says we're wrong." or something like that.

You read that on the IPCC website??!?!?

[anonymous-user]

This is a complicated question. Because you also burn calories after exercising as your body is cooling down.

You should also become more efficient as exercising in the long run, thus using less calories. I think that is why they invented the 'Perceived Exertion' index instead of relying on calories burned..

I am sure some boff can work out energy using it, but if you just took that figure you would be wrong.

[A3 Lucie]

8Ace said:

I spent half an hour on the cross trainer this morning. At the end of it, I felt pretty tired. According to the numbers on the readout, I burned north of 300 calories. Well done me. But I am assuming that this is simply a measure of the energy I was putting into the machine. As nothing is perfectly efficient (I know I'm not, I was sweating like a mofo at the end of it), does anyone know what level of efficiency I was working at. Ie: In putting in 300 cals worth of energty to the Cross trainer, how much did I use myself?

Any ideas? Would be interesting to get a vague clue.

The machine reading is telling you how many calories you've burnt...not how many calories the machine has recieved. So you burnt 300 calories.