As a regular hiker, from personal experience, moving from a 10 lb pack to a 20 lb pack (and heavier) starts to slow you down (and almost certainly if you are carrying the weight in your arms rather than on your back). If you are measuring purely by minutes, the decreased distance and increased weight tend to balance themselves out.
One option might be to use the walking tracker at www.caloriesperhour.com/index_burn.php where you can add 34 lbs and add the time and distance travelled, then enter the calories manually into Spark.
One way to estimate this is on the basis that each vertical feet is roughly equivalent to 8 horizontal feet. So if you added this to the horizontal distance travelled, in the same time, you would have a rough guide.
They're both estimates, and they may not necessarily have come from the same lab at the same time.
When I enter one hour, I get 681 vs 687 calories burned.
This is not significant enough a difference to worry about.
5/8/13 12:36 A
I had a related question - for the calorie calc, carrying a 10-20lb pack results in FEWER calories burned than a pack weighing under 10lb. Doesn't seem logical that carrying more weight would mean burning fewer calories!
I use it as an estimate to figure out how many more calories I may have burned while carrying my 34-lb child (literally in my arms - talk about a bicep workout!) when she falls asleep on a walk vs. just walking.
Remember it's just an approximation. If you are interested in accuracy, buy and wear a heart rate monitor.
Remember that Hiking will probably well over-estimate regardless. Both the tracker and any HRM you buy will include "BMR calories" in your calorie estimate. So if you're hiking for 5 hours, that's 5 hours worth of calories you would have burned anyway. This tends to throw off cardio calorie values once you start getting over an hour or so.
11/11/12 10:34 A
Hello! First of all - Thanks so much for such a great site, and incredibly supportive community. It's been so helpful for me over the past two years.
Regarding the Fitness Tracker, and how calories burned are calculated: Can you tell me more about the level of hiking intensity that is assumed for the "Hiking Hills" category? I do a lot of hiking, and many hikes now involve climbs with a steepness of approx 1000ft/mile (with total elevation gained anywhere from 2500 to 5000 feet) - To me that is much more strenuous than hiking "hills"? Is there a better category I should be using to estimate the calories burned?