Why is 3mph not always 3mph?

birgitkwood

Hi Folks, question: When I walk in my neighborhood with my dog, my GPS enabled Fitbit tells me that I've walked a total of 3 miles, and it's taken is exactly one hour. I have long legs and big feet, and I walk fast. The dog is trained not to sniff, pee or poop on our walk. During that hour we WALK, and at the end of that time we both feel well exercised.

So now it's winter and I've been going to the gym instead. I set the treadmill to 3mph and I feel like I'm barely moving. Not even close to fast enough for me. I scootch up the speed to 4.0, or even 4.5 to feel like I'm breaking a sweat. I set the incline on 3 (my neighborhood walks are somewhat hilly).

So what gives? Why is 3mph on the treadmill so different from 3mph in real life?

firef1y72

No wind to push against, totally even surface so less energy expended going up and down kerbs and keeping balance, no need to compensate for muddy, bumpy or grassy surfaces. No declines to counter the inclines. Constant temperature on treadmill, no need to expend extra energy keeping warm/cool.
I'm sure there are other factors, but that's a few I can think of.

MeanderingMammal

birgitkwood wrote: »

Hi Folks, question: When I walk in my neighborhood with my dog, my GPS enabled Fitbit tells me that I've walked a total of 3 miles, and it's taken is exactly one hour. I have long legs and big feet, and I walk fast. The dog is trained not to sniff, pee or poop on our walk. During that hour we WALK, and at the end of that time we both feel well exercised.

So now it's winter and I've been going to the gym instead. I set the treadmill to 3mph and I feel like I'm barely moving. Not even close to fast enough for me. I scootch up the speed to 4.0, or even 4.5 to feel like I'm breaking a sweat. I set the incline on 3 (my neighborhood walks are somewhat hilly).

So what gives? Why is 3mph on the treadmill so different from 3mph in real life?

I'd anticipate that your FitBit is wrong. Three miles in an hour is pretty slow, so from what you describe is be surprised if that was a 3mph experience.

The FitBit GPS implementation doesn't get good reviews.

vespiquenn

firef1y72 wrote: »

No wind to push against, totally even surface so less energy expended going up and down kerbs and keeping balance, no need to compensate for muddy, bumpy or grassy surfaces. No declines to counter the inclines. Constant temperature on treadmill, no need to expend extra energy keeping warm/cool.
I'm sure there are other factors, but that's a few I can think of.

This. Not to mention, the treadmill is doing the work for you. The belt moves rather than your body. I can go a lot faster on the treadmill than I can run outside because there aren't as many forms of resistance on the treadmill.

sijomial

3mph isn't a quick walk.
Something sounds off - is your Fitbit definitely using GPS for distance tracking?

You could use another GPS tracker on your phone to confirm - Runkeeper for example.
Or just trace your route on Google maps.

JamestheLiar

I have a suggestion to add to what others have said here. In my own experience, it is incredibly difficult to walk at a sustained steady pace for a given length of time outside. In fact, it's almost impossible to even know when I'm walking at a steady pace and when I'm not. A treadmill (as long as your weight falls within the machine's capacity limits) holds you to a prescribed steady pace.

The fact is, when you've walked three miles in an hour outside, that can only be taken as your average speed in that time ... not your constant speed. With that in mind, comparing your experience on the treadmill with your experience outside is a little like comparing apples and oranges. They're two different things - both good, but for different reasons.

birgitkwood

Thanks, Folks - you're giving me some really good explanations that make sense. But for those of you who think the Fitbit might be off, no - I've measured the same distance with my car and it's right on. I live in a very rural area, and I walk 1.5 miles straight in one direction, and then turn around and walk back the same distance. But in that stretch are two fairly steep hills/inclines. That's probably where the difference lays. Altho I always assumed that because I obviously walk up, and back down, those same hills that they'd balance each other out, exertion-wise. Apparently not.

JamestheLiar

You are probably doing it right ... rating your experience on how your body feels rather than an arbitrary speed/distance number. Set that treadmill where it feels right, and let the numbers fall wherever they want.

NJCJF

sijomial wrote: »

3mph isn't a quick walk.
Something sounds off - is your Fitbit definitely using GPS for distance tracking?

You could use another GPS tracker on your phone to confirm - Runkeeper for example.
Or just trace your route on Google maps.

this

firef1y72

birgitkwood wrote: »

But in that stretch are two fairly steep hills/inclines. That's probably where the difference lays. Altho I always assumed that because I obviously walk up, and back down, those same hills that they'd balance each other out, exertion-wise. Apparently not.

Don't quote me on this, but I wouldn't be surprised if it actually takes more energy to keep an even pace walking down a steep hill than walking on the level. I know that I have to make a conscious effort to keep my speed constant when walking/jogging down the 10% hill on my way to the gym, and then there's the way my centre of balance changes. I'm not saying it's the same amount of energy as going up the hill on the way back, but my than the comparatively level parts of my route.

ShammersPink

When I walk at 3mph for a decent length walk in a rolling rural setting, it feels quite fast, and I don't see many people walking faster, unless they are obviously "power walking". I don't think it is a slow "real world" speed at all.

I've done very little treadmilling - a small amount of running as part of circuit training years ago, and in that I could ramp up the speed far faster than my "real world" running speed.

MeanderingMammal

birgitkwood wrote: »

I've measured the same distance with my car and it's right on. I live in a very rural area, and I walk 1.5 miles straight in one direction, and then turn around and walk back the same distance.

In that case you may find that the treadmill is out of calibration.

Altho I always assumed that because I obviously walk up, and back down, those same hills that they'd balance each other out, exertion-wise. Apparently not.

As you increase vertical elevation you're working to lift yourself as well as move forward, so it is more work. Your pace climbing and descending will vary, but at an average of 3mph there isn't much scope for variation.

cwolfman13

3 mph is a nice stroll in the park...it feels the same to me either way except the treadmill is more boring.

CMNVA

I don't feel like I am a fast walker at all but I have a 3 mile route that I can do in about 45 minutes. But I know what you mean about the treadmill. 3MPH on that thing seem incredibly slow.

cosmonew

I can totally walk about 4.5 on the treadmill, yet hauling butt with my fitbit I am walking 3 mph...just like you said. I have heard that in order to get the same effect as walking outdoors the treadmill should be set at a 2.0 incline.

genpopadopolous

CMNVA wrote: »

I don't feel like I am a fast walker at all but I have a 3 mile route that I can do in about 45 minutes. But I know what you mean about the treadmill. 3MPH on that thing seem incredibly slow.

That's because you are doing 4 mph outside.

If you were doing 3 mph it would take you a whole hour to do your route.

heybales

Hills don't balance each other out energy use-wise or rarely time-wise.

It's estimated that downhill takes 55% of the amount of energy as uphill would take - same incline same pace.
Except most go down faster then they went up, but still usually less.

So that means if you had 5% incline for say 1 mile, that would be about equal energy wise to 2.75% incline to take the place of the downhill.

But GPS for getting altitude is pretty bad - but some sites correct for it using known records of height, if truly curious what it is out there.

Also consider the treadmill may not have been calibrated for a long time if ever. It's distance may be off. Sometimes pretty bad.

I've only seen one get calibrated - and that was when belt had bad fray and got new one - the company that came in to do it included that.
The gym personnel said they never did the others. They offered to come back. The gym said no.

I used one next to it another day, matching speed of belt with someone using it (you can see the marks) - displayed speed was 5.7 mph on theirs, 5 on mine. That was pretty bad. But who would have had a clue. We assume it feels different than outside because it is for many other reasons. (walking and wind resistance isn't one of them, unless mighty windy outside all the time)

FasterBehr

Just a thought, but perhaps the treadmill was set up in kilometres per hour and not miles per hour?

trigden1991

3mph is always 3mph (well technically only when represented as SI units, M/S).