Maybe. But what I meant is: When I first started riding at 220 lbs and out-of-shape, I burned a lot more calories on a shorter, slower ride, than I do now at 180 lbs. and being much more fit. Granted, I go faster and further now in the same time....but if i were doing the same ride at the same speed that I started out doing, I'd probably burn half the calories that I burned then.

How can one do 170 percent of their vo2 Max? One of the highest vo2 max a rider has ever recorded is 97.5 ml/kg/min. Or so it has been reported. 170 percent puts him at 165.75 ml/kg/min That is just slightly below a race horse vo2 Max. Unless there is a source of EPOs you are holding back on us.

V=Volume O2 = oxygen and Max = Maximum You must have been thinking of something else. But you are correct the more you ride the less you burn per mile based on fitness.

170% VO2max is the standard Tabata protocl: https://robertsontrainingsystems.com/...e-tabata-myth/

https://www.ncbi.nlm.nih.gov/pubmed/8897392

I didn't understand it at first either- How can one be over 100% breathless? Hence, why real Tabata is so hard...even though of such short duration (And also why it yeilds amazing results!)

That has to be a formulated vo2 max. That can not be a machine measured vo2 max because you can not exceed you maximum intake of 100 percent. Since I can't see any gym testing on a machine, Direct testing is the "only" way to measure vo2 max. looking at the link you posted they set the resistance to 170 percent of the effort you normally use to reach your 100 percent exhaustion level. But understand 100 percent vo2 max is the point where you can no longer exercise and vomiting often starts. From the Sports medicine site I checked "Measuring VO2 max accurately requires an all-out effort (usually on a treadmill or bicycle) performed under a strict protocol in a sports performance lab."

As you may know the USADA and the UCI have been working on tests to measure the vo2 max of riders and anyone that ever tested at 170 percent would be bounced for EPO. But I agree if someone could suck in 170 percent of the oxygen necessary to continue racing, running or exercising that would be difficult. Sounds like some people estimate vo2 max like others do calorie counts.

VO2max is the maximum power you can produce aerobically. On top of that, there are short-term muscle reserves and anaerobic pathways.

There's an approximate formula: VO2 (ml/kg/min) = 11 * power (W/kg) + 7

If my power at VO2max is 4 W/kg (my lactate threshold would be lower - say, 3 W/kg?), my VO2max would be 11*4+7=51 ml/kg/min.

At the same time, I can do about 11 W/kg for 20 seconds (power meter numbers). That would be 275% of VO2max. Most of it would be coming from anaerobic reserves/pathways.

Sounds a lot like the formula for maximum heart rate.

Yes, when MetalPedaler says "170% VO2max", he means 170% of power at VO2max.

Now I agree. The formula was confusing me. from the same medical source:

"VO2 max, or maximal oxygen uptake, is one factor that can determine an athlete's capacity to perform sustained exercise and is linked to aerobic endurance. VO2 max refers to the maximum amount of oxygen that an individual can utilize during intense or maximal exercise. It is measured as "milliliters of oxygen used in one minute per kilogram of body weight." V02 max should not be confused with the lactate threshold (LT) or anaerobic threshold (AT), which refers to the point during exhaustive, all-out exercise at which lactate builds up in the muscles during exercise. With proper training, athletes are often able to substantially increase their AT and exercise longer at a higher intensity."

I have been trying to get my doctor to send me for a vo2 max test so my insurance would pay for it. So for my excuses haven't been convincing I guess?

How long it takes you to reach an O2 consumption of VO2Max is a function of intensity above your threshold power. If you ride at 200% of FTP you'll reach VO2Max faster than if you ride at 110% of FTP. Basically, any effort above FTP will eventually cause you to your O2 consumption to reach VO2Max.

When studies refer to VO2Max power it is in the context of a prescribed ramp test, typically starting at 100-150W and going up 25W every 3 min.

So in the Tabata study when they refer to power at VO2Max you need to look at the ramp protocol they used. As a rough guide power at VO2Max is roughly equal to the average power you can put out in an all-out 5min effort. Doing 170% of that power for 20 Seconds is easy. Repeating it 8 time with minimal rest is the difficult part.

I am not Mark Cavendish, but I have, on a few occasions, managed to maintain power output in the neighborhood of 800 W for short intervals. The best result was 800 W for 20 seconds. Golden Cheetah estimates that I have "anaerobic work capacity" of 15 kJ. I think that 1300 W for 20 seconds is still well within the potential of an amateur cyclist, it mainly requires some weight training and muscle muss building.

4x 30 s intervals to exhaustion with 30 s breaks, each time expending 15 kJ anaerobic and, say, 6 kJ aerobic (200 W for 30 s), allow for lower metabolic efficiency of anaerobic work... I can see 150 calories here. 300, I'm skeptical. 750, I'm extremely skeptical.

You can do all the weight training you like but if you didn't pick the right parents it's not going to happen. Andre Greipel doesn't put out 1300W for 20 seconds at the end of a race so I don't think many amateurs will

Maybe not 1300 for 20 seconds, but four digit short-term power numbers are often quoted by amateur racers.

I'm not a fitness guru, so I could be wrong, but the way I understand it, in layman's terms: You achieve 100% VO2 when you become breathless. Increase your output from there, and you get it up over 100%. At least that's the way I think of it.

I know I am not achieving 170%. I'm probably getting a little up over 100%. Funny thing is, since i started doing the Tabata, my VO2 capacity has increased so dramatically, that it out-paces my muscles- in other words, I now max-out my muscular strength long before I max-out my VO2....so I can not go hard enough now, to elevate my VO2 any more. (In the original Tabata study from 1996, they did not have this issue, as they used trained athletes....).

It might work for you it is just that the medical sites tell us is you can increase your oxygen uptake to level that becomes your new vo2 max. the power produced beyond that is a different measurement. " V02 max should not be confused with the lactate threshold (LT) or anaerobic threshold (AT)"

But at least I now know what you were talking about. It was like when I told my doctor that on a sprint I can exceed my max heart rate by 10 to 15 percent. All the formulas said my max HR is 163 and after the last fie years riding I can hit 183 flat out on a sprint. She smiled and said, maximum heart rate is not something a formula and tell. It takes testing equipment.

Looks like there are a lot of things that are as misunderstood as calorie burn.

Largely nonsense, I'm afraid. You'll burn fewer calories because you are shifting less weight at the same velocity, and therefore using less power. The difference will be minor on flat ground and will have nothing whatever to do with how fit you are.

Being fit allows you to burn more calories in a given time by maintaining a higher power output. It makes absolutley no difference to how many calories it takes to shift a given weight at a given velocity.

Regardless of the number of calories, the key to losing weight is adjusting your diet. No amount of excercise will work without also eating less, and healthier.

Exactly! Few of us have the time or inclination to truly exercise enough to burn even one pound (3500 calories) per week. Although, high-intensity stuff like Tabata does help, due to the afterburn (A 4 minute Tabata drill actually seems to do me more good than a 25 mile hilly bike ride)

Is this really true? Certainly the mechanical power required at the pedals will not change. But I would be surprised if conditioning doesn't change the efficiency of turning food calories into mechanical energy.

For example, wouldn't a given power output that's in the anaerobic zone for a novice then become an aerobic possibility after conditioning? Doesn't aerobic metabolism produce more mechanical energy out for the same food calories in?

Me and my GF did 22mi today. I wear a HRM connected to a Garmin 510 and she simply plugs in time and average speed into myfitnesspal. My calories from Garmin for the 1:45 ride was under 400 ... Myfitnesspal told my GF she burned over 1,000 for the same ride. Granted I'm in a lot better shape than her and my average heart rate for the ride was just 88, but I'm pretty sure the 1,000 cal estimate from myfitnesspal is way high for her ad well.

+1 to everyone who said if you want more accurate calorie burn data, get a HRM.

I use 30 cal a mile as an estimate and I agree effort plays a huge role. If your cycling to lose weight you need to weigh and log everything daily to keep an accurate count of your net calories. Doing that over months tells you how your net calorie burn equates into fat burn. Me for example, 1300 net per day equates to about 400 calorie fat burn per day (BMR of 1750 per day) and 2800 calories burned per week which translates to 3+ fat pounds a month burned. I use My Fitness Pal for the diary but I never use it's calorie estimates on cardio (biking). Logging stuff tells you interesting things. Eating casually (not really paying close attention) I maintain weight at 50 miles a week and begin to lose weight at 80 miles a week and by focusing on eating patterns...I really start losing weight at 100 miles a week. Of course I could just eat 1300 calories a day and not ride but...life gets boring then.

A long time ago I rode 4000 miles in 60 days and lost 1 pound. I was 153 pound skinny 5'10' 21 year old burning through say ~4000 calories a day (2000+ BMR and 2000 cycling say 70 miles...pretty typical average touring mileage). I also ate a lot....4000 calories a day, some days less, some days more and it is very easy to eat 4000+ calories a day if your eating constantly a diet of bread, bananas, peanut butter, GORP, milk, ice cream, chocolate, honey, jam, apples, all you eat buffets, whatever is edible is eaten. What amazes me is how efficient the human body is on a bicycle.

I know it took a lot more power and burned a lot more calories propelling my then 221 lb. carcass up the hills, than it does now, that I weigh 181 !

Yes

Not as far as I know. Why would it? What certainly does happen is that as one trains, the intensities at which one draws most of one's fuel direct from fat will tend to increase. As a result, one will conserve one's glycogen stores and be able to go harder, for longer. But it is the increased duration and intensity that burns more calories, not some change in the relationship between calories in and calories out. Going the same distance at the same power output will burn the same number of calories it ever did.

Calories burned depends on a number of factors -- your age, weight, speed, level of exertion. I would recommend a free website/app called loseit.com

I have used LoseIt to successful drop 30+ lbs. and maintain my target weight for past couple of years. You have to track both calories eaten and burned through exercise to make best use of the site/app. The LoseIt program automatically adjusts your calorie burn from exercise to your weight. For instance, as you lose weight, you burn fewer calories from a given amount of exercise because your body needs less energy to perform a given task at a lower weight. It also adjusts your calorie burn to your level of exertion -- which is approximated by your average speed. For example, I burn about 725 calories/hour cycling in the 14-16 mph range but about 800 calories/hour when cycling at 16-18 mph.

Based on my numbers, I would think that 1,000 calories/hour is an overestimation of your calories burned cycling at 12 mph.

The sheer banality of this post is worthy of remark. Did you actually read the thread?

Well, I am no biochemist, that's for sure! But from what I have read... for example:

https://en.wikipedia.org/wiki/Cellular_respiration

This article talks about the number of ATP molecules produced per glucose molecule using different energy pathways. "Aerobic metabolism is up to 15 times more efficient than anaerobic metabolism."

What amazes me is how slow I am on a bike. OK, I have a heavy bike, and my BMI is in the 25 zone. But seriously, I keep my heart rate up around 140 - I am 57 yrs old - and I sure am not getting anywhere too fast! Oh well, I enjoy the scenery and it must be keeping me half way healthy, despite all my limitations!