Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board Question for overweight hikers

If your formula does not apply to climbing, then we don't have anything to discuss because that is the only topic that is meaningful here (and it is the only one that we've been discussing from the beginning of this thread - fat/calories burned climbing Whitney).

Just to point out one final case of you don't know what you are talking about - it is absolutely certain that Sue Nott did not just lose 10-15 pounds of water weight on a multi-day climb of the Eiger. You lose water weight (primarily) during the period of time when you burn through glycogen stores (glycogen is stored in water in your body and the water is excreted as the glycogen is used), which happens in the first 12 hours or less on a big mountain climb like Eiger. After that, you start buring fat and even muscle when the body goes into a catabolic state as you expend far more calories than you eat. The Eiger is about the same height climb as Whitney (I've done both), and as you can plainly see from this example, uses way more that the 1 pound of fat calories that you claimed it would take to climb a mountain like Whitney.

I'd suspect a significant amount of her weight loss to be attributed to dehyrdation.

enuff-

If you're not interested, what compels you to click on this thread and read it again and again? The issue of coloric requirements is very important in climbing. If you're not interested, don't read it.

ScottM- I didn't put her entire message, but she did say that she made of point of being well hydrated. Melting snow and drinking tea is usually the #1 activity on big climbs when you are bivvying. While I agree that a pound or two is probably water weight, there is no way that 5 - 10 is, that would be a gallon of water and she would not be able to climb at that level of dehydration.

WAclimber -- There is a reasonable thread on this board about terminology -- hiking vs. climbing. I particularly like the definitions posted by Alan (no relation to me). Both hiking and climbing are relevant to the board. I have made it clear that the data to which I refer apply to walking and/or running, both on flat surfaces and uphill. Those data are very relevant to the majority of people who ascend Whitney -- by hiking. I have expressed interest in data relevant to climbing but have not posted any. I never said my posts had all of the information anyone could ever want.

My assertions have been based on real data. I am not going to argue back and forth based on anecdotes with essential data lacking. It is easy to lose over 10 pounds of water during hard endurance exercise. As I said, I do not believe that a very fit 120 pound woman lost 15 pounds of fat in a climb for the simple reason that she did not have that much fat to lose in the first place.

I agree with you that neither of us should be trashed for having a conversation that is highly relevant to this board. Debate can be a great way to advance ones knowledge. Potshots like the ones we've seen come from people who would be burning books if they had the matches. I love the fact that these guys hang on our every word and then cry "stop it before I read again!"

Nevertheless, do think that, at this point, our particular conversation would best be continued off of the board -- if you are interested.

From my perspective, this has been an interesting and useful discussion. I also appreciate that both WAClimber and AlanK took the high road and avoided any flame throwing.

Enuf & wasted bandwidth: this isn't a matter of two people talking loudly 'on the front porch' as enuf put it. In order to hear this discussion, you had to walk through the closed front door (by clicking on this thread) and walk waaay to the back of the house (by scrolling down through about 70 posts). Why you would continually do this to overhear a conversation that bothers you completely baffles me.

Enuff,

1. If the moderator thinks that our conversation has strayed too far afield, he has the power (and the right) to delete our posts. I doubt that he needs you to be whining "Daddy, Daddy, they're breaking the rules."

2. Candace's topic for this thread, "Question for overweight hikers" clearly violates your sense of what belongs here. You can save yourself a lot of pain by not clicking on such an obviously irrelevant (by your standards) thread. But you can't do that because your entire purpose in reginstering here is to be a busybody -- to police others.

3. "Clearly not qualified" and "flawed information" are meaningless, coming from someone who has contributed nothing of substance and supplies no facts to back up his judgements.

WAclimber and I have a disagreement on a topic of interest here. We may have reached the point of diminishing returns in this particular discussion, but at least we both post material (now and in the past) that relates to the topics that this board has been covering and debating for years.

Warning: The following data on energy expenditure in high altitude mountaineering was obtained in a study of climbers on Mt. Everest, not Mt. Whitney. Some of you may find it to be irrelevant for that, or other, reasons.

A group of physiologists (K.R. Westerterp, et al.) studied Mt. Everest climbers for 7-10 days as they approached the summit. They published their results in Journal of Applied Physiology, vol. 73, p. 1815 (1992). For prolonged, strenuous exercise at altitudes well above that of Mt. Whitney, the climbers expended an average of 13.5 MJ/day.

That's 3250 Calories per day.

This thread has moved quite a bit off of the original topic, but I like it! And here are some meaningless stats that I'll throw into the discussion:

On 8/10/03 I climbed Whitney up the MR in 3:34. Total time, round trip, was 8:23. I weighed about 140 lbs. at the time. My Polar s810 computer told me that I burned around 5332 calories. That works out to 636 calories/hour.

On 10/25/03 I climbed Whitney up the MR in 5:02. Total time, round trip, was 10:35. I weighed about 150 lbs. at the time. Calorie consumption was around 6699 calories. That works out to 633 calories/hour.

The numbers look fairly constant to me (Although I'm not a scientist!), but higher than AlanK's figures.

Here's how the computer makes the calculations: "In Polar S-series Heart Rate Monitors, OwnCal calculation takes into account VO2max, HRmax and exercise heart rate.
The calculation starts when your exercise intensity reaches 60 % of your maximum heart rate or 90 bpm - whichever is lower."

On March 17, 2004 I left the US for a climbing/trekking trip to Nepal. I weighed around 155 lbs. when I left. On May 2, 2004 I weighed myself on returning to Thailand. I weighed around 136 lbs (62kg). Granted, I had more stomach problems on this trip than usual, but when I wasn't sick, I ate like a pig. A normal dinner, if we were in a lodge, would consist of two, or three, main dishes. I think that you'd find a consensus among high-altitude climbers that it is nearly impossible to eat enough to prevent weight loss while at altitude. And, I don't think that it was water loss. I usually consumed in excess of four liters a day. (I don't have any scientific evidence to support my comments.)

I find that my "perceived" fitness is at it's peak when I weigh around 140 lbs. If I crack 150 lbs, I find the going quite a bit harder. At 155, and above, I'm suffering. So, for me, it takes only a little bit of a "spare tire" to make physical activity more difficult. At my age, I also find it very difficult to stay down in the 140 pound range.

Richard P -- I would expect my formula to break down in going from walking to climbing, which burns calories faster (per distance travelled) than walking or running. In the case of the MR, the steepness alone would raise my prediction to well over 3000 Cal for the ascent alone (the figures I gave were for the Main Trail). If you tell me the distance you covered, I'll see how it comes out.

Regarding your other comments, you and most other high altitude mountaineers are correct. A major conclusion of the study of Everest climbers that I cited was that they don't come close to taking in as many calories as they burn. The body just doesn't cooperate. I was going to comment on that point, which should be of great interest here, but backed off because our discussion was attracting more trolls than serious comments at that point.

Thanks for your comments.

Alan,

If I remember correctly, a couple of sources have calculated the length of the MR to be 4.3 miles.

Is it the incline that is going to affect your calculations? Remember, other than a couple of short sections (EB ledges, cliff below Iceberg and the final chute), the MR is still a walk-up.

Richard -- The formula I posted, which was obtained by fitting some published data from treadmill studies, states that energy expended walking increases in proportion to distance travelled and body mass. It also increases rapidly with slope. However, the data I fitted covered slopes from 0 to 25%. The main Whitney trail averages something like 10%. The MR (at 4.1 miles) averages 29%.

In familiar units, for a 150 pound person, my formula is:
energy/distance = (93 Cal/mi)*[1 + 8.38*tan(A)], where E is energy used and, d is distance covered, and A is angle (with respect to horizontal). The tangent, tan(A) is the fractional grade -- 0.10 (10%) for the Main Trail and 0.29 (29%) for the MR.

Thus, a person burning 93 Cal/mile on the flat burns 170 Cal/mile on a 10% slope and (extrapolating) 320 Cal/mile on a 29% slope. That gives around 1310 Cal for 4.1 miles of uphill. (I made a mistake in my previous post -- I forgot that I was working with closer to 4 miles than 11). I found no good data for going downhill.

That's fewer calories than your monitor calculated. However, I would not be surprised of the formula breaks down badly for steep slopes. That's pretty obvious in the extreme. One may burn ~100 Cal walking a mile but it takes a *lot* more to climb a mile of vertical wall. I suspect that you burn calories at a much higher rate in the steepest sections of the MR.

All in all, I would not push the use of the formula for anything beyond straightforward hiking up modest slopes. It makes the useful point that you burn a lot more calories going uphill than on a flat trail.

As I said in an earlier post, I'd love to see data on walking/climbing steep slopes. Whan I find some time, I will try looking more diligently myself.

Regarding the Everest study I cited, the subjects expended an average of 3250 Cal/day for the 10 day study but took in only 1890 Cal/day. The deficit was 13,600 Cal over the 10 days. The subjects lost an average of 1.2 kg of fat (not total weght loss), which accounts for 10,800 of those missing Calories.

Richard P -- it would seem that a HR monitor device adjusted for sea level O2 (oxygen) partial pressures in the atmosphere would overestimate calories burned at high altitudes if basing caloric consumption on heart rate. At altitude your heart rate will be accelerated with lower oxygen pressures for a given amount of exercise. I always considered aerobic "fitness" to be the body's ability to use oxygen, and using heart rate as a marker for oxygen consumption has to be adjusted for altitude.

I used 2 different treadmills yesterday and walked a mile on each at a 10% grade, the equivalent of an average mile on the main trail going up. I weigh 140 pounds and punched in 155 pounds on the treadmill to account for my 15 pound pack. It calculated a caloric expenditue of 168 calories per mile. On the way down I would estimate that one would use closer to a level mileage rate of calorie usage (my treadmills didn't have downhill modes to check), so I estimated 100 calories per mile down. This works out pretty close to Alan's formula arriving at 3000 calories for the round trip hike. Now the treadmills may be using Alan's formula in their calculations, but I thought it was interesting how few calories I really would burn up. A pound of fat on your body represents 3500 calories stored up, so if one didn't diet at all just less than a pound could be lost for each hike up Whitney. A tough sell compared to other weight loss plans!

This is my first post and I appreciate all the info on this site. Thanks everybody. I'm hiking Whitney for the first time June 10 and will be looking for current ice conditions.

Joeski

joeski-

keep in mind that your body is doing much more work at altitude than it does at sea level. You are burning more calories when just sitting still up high (which is somewhat baffling since your blood pO2 is fairly normal when resting at altitude until you get pretty high). For example, your body is producing new red blood cells at a very high rate in order to adjust for the reduced amount of oxygen. In addition, you are losing muscle efficiency since your blood pO2 drops well below normal when you are climbing with a pack up high. So a hike on a treadmill at sea level doesn't translate terribly well into a climb up Whitney (as if your body doesn't already tell you that in spades).

Point well taken, Joeski.

I'm going to see if I can't get someone at Polar to comment on your statement. One of the "problems" that I have with AlanK's formula is that it can't take fitness into consideration, and I can't see how fitness isn't a factor in how many calories are burned per mile.

How'd your first ascent of Whitney go?

Richard P. -- You raise the interesting issue of how much fitness matters in how many calorie dissipation per mile. I believe that the answer is "not as much as you might think."

The formula I posted was the result of fitting a simple equation to data, from several sources, on how the slope of a course affects energy expenditure. There are two pieces to the result. One is the familiar 100 Calories per mile for a 150 pound man. The other piece covers the additional calories burned when going uphill. The point is that increasing the slope increases the total rather impressively. However, we can start discussing your point by dealing with only the first piece.

I've seen the "100 Calories per mile for a 150 pound man" result printed in numerous places for at least 25 years. Something close to that figure has been obtained in many studies, covering subjects whose fitness varied widely. Some of the studies have been on average people, some on athletes.

As with all statistical studies, there are individual variations in that 100 Calorie/mile figure. However, the variations are on the order of +-10%, not huge. These presumably reflect variaitons in efficiency. I would expect a trained athlete to be more efficient (i.e., use fewer Calories per mile), but there seems to be no evidence for this.

I am also looking for more data on this subject. I am interested in data that support or don't suport my conclusions. If you are interested in discussing it in more depth, feel free to contact me at AlanK987@hotmail.com.

As a result of this thread, I have received e-mails from two ultramarathoners who have added considerably to my understanding of the subject. One recently published an article describing measurements of his calorie consumption during the first 40 miles of the Western States 100 mile race. They were in the range one would expect. He is obviously a fit subject!