The FastDay Forum

Running is more efficient than walking at high speeds ie there's a point where walking faster you should switch to running. http://www.brianmac.co.uk/energyexp.htm has a nice picture (see below). Power walking at 10 km/h uses more energy than running at 10 km/h

I would agree about doing the one you enjoy most, but I wouldn't go seeking any justification for it.

According to this manufacturer's bumph (slower speed + greater incline burns more fat cals than higher speed + no incline):

http://www.freemotionfitness.com/wcsstore/Freemotion/Attachment/Education/Incline_Training.pdf

"Perhaps the most significant finding of this research was the change in fat utilization at slow
speeds and high inclines. With increased muscle activation at higher speeds and inclines,
calorie expenditure increases. If only speed is used to increased energy demand, the body
must use more and more carbohydrates as fuel because fat utilization takes too long.
However, with the use of incline to increase demand while keeping the speed at 2-3 mph,
physiological measures and calculations such as oxygen consumption and respiratory
exchange ration demonstrated that fat utilization increases dramatically. It was hypothesized
that the slower speeds allowed the processes involved in fat utilization to keep up with the
energy demand. At 2 mph and 16% incline, over 6 calories per minute from fat were utilized.
This was compared to less than 2 calories per minute from fat used at 6 mph and 0% incline"

That's interesting, LastChance -- I wonder, with those kinds of inclines (you can't get above about 10% on a standard treadmill I don't think) you might as well just hit the stairstepper (or just climb stairs... and take the elevator down because going down stairs hurts your knees lol)?

Izzy, I wasn't trying to choose between running and walking, I was more thinking of transitioning to walking from running and wondering how much longer in time and distance I needed to walk in order to get comparable benefits (without the wear and tear associated with running).

I did some calculations and wanted to come back here to share them, and also to restate my problem statement so it is more-clear.

Consider a person who is currently running/jogging about 12 miles per week on a 10 min/mi pace for a total of 2 hours of exercise spread out over 3-4 days. This person wants to transition from running to walking for various reasons but doesn't want to lose out on too many of the benefits of their current exercise program in exchange for the perceived benefits (e.g. less wear-and-tear on the joints, less money spent on shoes, more-flexible exercise schedules that don't require changing clothes or showering, things like that).

How much walking, distance and time, at a pace between 15 and 20 min/mile (3 to 4 mph) on a small-to-moderate incline so as not to break out into a deep sweat, would they need to do to reproduce most (preferably all) of the health benefits of 12 miles of running in 2 hours per week?

Method used for analysis: hold calories expended constant, but subtract BMR for the time spent exercising because I could be napping.

I looked at my weight when I started (226 lb) and my current goal weight (174 lb), and held my age and height and gender constant, and here is what I found (I used http://thefitgirls.com/calories-burned-calculator.aspx for the cal/hour numbers and BMR numbers for the various paces of running and walking):

226lb
BMR: 2070/day, 87/hour
6.0mph run pace: (844/hour-87/hour)/6.0mi = 126/mi
4.0mph walk pace: (431/hour-87/hour)/4.0mi = 86/mi
3.5mph walk pace: (371/hour-87/hour)/3.5mi = 81/mi
3.0mph walk pace: (302/hour-87/hour)/3.0mi = 72/mi

174lb
BMR: 1746/day, 73/hour
6.0mph run pace: (713/hour-73/hour)/6.0mi = 107/mi
4.0mph walk pace: (364/hour-73/hour)/4.0mi = 73/mi
3.5mph walk pace: (313/hour-73/hour)/3.5mi = 69/mi
3.0mph walk pace: (254/hour-73/hour)/3.0mi = 60/mi

Starting with the 12 miles of running in 2 hours, I get 1512 calories at 226 lb and 1284 calories at 174 lb. The number of miles I need to walk at the various paces to get to that calorie expenditure is as follows:

4.0mph walk pace: 226lb--17.6mi/4.4hr ; 174lb--17.6mi/4.4hr
3.5mph walk pace: 226lb--18.7mi/5.3hr ; 174lb--18.6mi/5.3hr
3.0mph walk pace: 226lb--21.0mi/7.0hr ; 174lb--21.4mi/7.1hr

So, it looks like I would need about 18 to 20 miles of walking over a 5 to 6 hour time period per week to get to rough equivalency to the 12 miles of running in 2 hours.

That gives me a sense of the requirements, at least to get caloric expenditure equivalency, but now I'm wondering if caloric expenditure equivalency is the correct measure? Also, assuming I transition from running 12 miles a week to walking 18-20 miles a week, what should I expect in terms of overall health benefits, etc. and what might be better and what might be not as good?

I know one thing I'd miss is the endorphins... I really like post-run endorphin levels.

"This person wants to transition from walking to running" - other way round ??

LOL yep -- I fixed it. Good eye!

Just one more quick comparison -- the "10k per day" guidelines of walking 10,000 steps per day comes to about 35 miles per week, though they estimate that most sedentary folk manage to get about a third of that without deliberately going out and walking for the sake of hitting their daily 10k target. That still leaves about 23 miles for the week, so my estimate of 18-20 miles may be a little on the low side...

Either that, or I'm perhaps overestimating the benefits of 12 miles per week of running at a 6mph pace?

A lot of sedentary people come nowhere near 3,000 steps per day - some barely manage 300 !

A heart rate monitor (properly set up for your fitness) would nail down the current benefit. Running for 2 hours I would use an extra 600-800 calories over sedentary. 5.6 mph.

I have a decent hrm, but it's not clear to me how to compare, say, 2 hours at 155-165 bpm versus 5-6 hours at 125-135 bpm. At 43 years old the 220 minus my age comes to 177 bpm max heart rate. Assuming that's in the ballpark, which one is better, or are they pretty close?

http://www.shapesense.com/fitness-exerc ... lator.aspx

Found that calculator. Should be a good start to figuring out my question. Thanks PhilT!

Huh... the heart rate versus net calorie burn (subtracting BMR) for me right now ranges from 559 to 1119 cal/hour over a range of 65-100% of my max heart rate (116-178bpm), and it's pretty much a straight line according to the website calculator I found above.

I was thinking it would be more nonlinear and/or a much steeper slope. If a heart rate of 65% of max burns calories at a rate that's 50% of the rate for the same time at maximum heart rate, caloric equivalency between running and walking happens in less than double the time (assuming, of course, that your walking pace is fast enough to get your heart rate up above 65% of maximum).

This makes me wonder -- if the 10k/day guidelines imply about 35 miles per week in about 10 hours of walking, would I need 5 hours of running per week (30 miles) to get the same net calorie burn?

These numbers aren't adding up... I haven't measured my heart rate while walking recently. Maybe I'll do that today. I do measure it when running pretty much every week, especially during cooldown because I end on a sprint + high incline and then walk for 5 minutes and my heart rate comes down from ~175bpm (near 100%) to just below 130bpm (~70%) in that 5 minutes.

I looked at some walks - to the shop in the next village and back. Average HR was 118 in one case, 230 cals in 40 minutes. It's about 1.8 miles round trip but the time includes the shop. Another one was 157 cals in 33 minutes. My (measured) RMR is about 1600-1800 so say 75 per hour. Max HR is about 175, I'm 52, anaemic and aerobic fitness is about 25-30 ml/kg/min VO2max.

Interval running & walking (C25K) I will average about 145 - 150 bpm and clock 380 cals in ~50 minutes.

My Polar F6 is set up with my VO2max data.

Since getting the Polar and doing the C25K program I find I can't keep my heart rate much over 125 by walking, have to do bursts of running to do that.

I like to run for the challenge and competitiveness it brings. I like to walk for my leisure and enjoyment. I think both activities have their own merits, but they are different activities that have their own place and time in my day to day life. Any movement is better than none...do whichever you like, and have fun :0)

I find I can't keep my heart rate much over 125 by walking, have to do bursts of running to do that.

Yeah, I just finished up a few experiments with my Polar hrm:

Walking, casual pace
A little over a mile, 27.5 minutes, ~2.4mph
(Note on pace--we stopped three times for the dog to meet a little girl and two other dogs and neighbors on a leisurely, sociable pace. Had we not stopped, I would guess we were going roughly 3mph.)
Ave hr: 89bpm (50%)
Max hr: 104

Walking, moderate pace
3.1 miles (measured by car odometer a while ago), 51 minutes, 3.65mph
(No dog this time, no socializing, just me. Pace was set to try to push myself as fast as I could go without breaking into a full-on sweat.)
Ave hr: 100bpm (56%)
Max hr: 117bpm

Basketball with son, one-on-one, low-moderate exertion
20 minutes
(Again, just on the edge of breaking a sweat, similar to moderate walk.)
Ave hr: 99bpm
Max hr: 117bpm

So, it seems I need to break into a full-on sweat to sustain a heart rate above 116bpm (65%).

Tomorrow I'll monitor my hr during my treadmill run and see where my ave bpm comes in to compare.