iPhone Health app severely undercounts distance?

So, like a large number of other people who've posted here, I'm having trouble with the distance reported by the Health App on my iPhone (in this case, an iPhone 12 Pro Max). The circuit I'm currently walking daily measures as approximately 2.3 miles on the map (it varies by a few tenths of a mile in different apps, but this appears to be the median measure), but the Health app is recording it as only 1.7 miles, a discrepancy of roughly 25%.


I first suspected there was a problem some time ago, when I used a treadmill on a bad-weather day and saw that where the treadmill recorded a mile traveled, my iPhone recorded only .8 miles. I wrote that off at the time to the fact that I'm not actually going anywhere on the treadmill, but I've since verified that the iPhone doesn't use GPS to track distance traveled at all, only the accelerometers. So I used several different map apps to trace my current route.


I've found several different posts here with people experiencing this issue on a variety of different iPhones, and at a variety of times (implying a variety of iOS versions). They always get told to contact Apple Support, and many report back that the contact was not helpful.


I don't have an Apple Watch—I'm planning to get one, but I don't have the spare couple hundred dollars for one right now. I've verified that my height is recorded correctly in Health (5' 5"), which was the source of one person's problem. The step length seems a little short, though, compared to my actual steps. I tend to take longer steps than is typical for my height, because I spent my high school and college years keeping up with much taller friends.


Should I adjust my reported height to account for the discrepancy, since I can't directly adjust the step length recorded? I know that once I get an Apple Watch, the measurements should be more accurate, but in the meantime, I'd like to have better data in my Health record. Are there any real solutions to this issue that seems to be fairly common?

iPhone 12 Pro Max, iOS 16

Posted on May 12, 2023 5:31 PM

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May 13, 2023 12:36 PM in response to MarquelleDavianMcKean

Update: I have verified that the step length being recorded is reasonably accurate, though it's hard to verify it precisely when it varies depending on the situation. I have also determined that the step count times the step length does not match the distance listed.


As of this moment, my step count for today is 5,245 steps. The average step length listed is 24–27.6 in. This averages to 25.8 inches. 25.8 inches times 5,245 steps comes out to 2.14 miles, but the walking + running distance shown is 1.7 miles.


Furthermore, neither of these figures matches the actual distance of my daily circuit, which as I stated above is about 2.3 miles. If I multiply the last step length shown for that walk, 27.6 inches, by the day's step count, I get 2.28 miles, which is close to my circuit length, but still under the measured distance. Based on the steps recorded outside of my workout, my total distance for the day so far should be closer to 2.5 miles.


If, conversely, I multiply the shortest step length recorded today, 24 inches, by the day's step count, I get 1.99 miles, which is still greater than the 1.7 miles Health has recorded for today so far.


Also, the provided walking speed for the hourlong period of my workout ranges from 2.3 to 3 mph. Even the lowest speed for this period returns a greater distance than I calculate for the shortest step length.


So now I'm concerned that there's something more seriously wrong with Health than just a possible accelerometer calibration issue. The math for the figures it's showing doesn't add up. If the step count and step length are accurate, then the distance is definitely wrong, because the lowest possible distance for the steps and length listed is greater than the distance shown. And if an hourlong walk records a speed as high as 3 miles an hour, the distance being recorded is potentially as low as half the actual distance traveled.


So what's going on here??? If the accelerometer-determined distance is naturally this inaccurate, why doesn't the iPhone include GPS information in the calculations when not using an Apple Watch? It's not as though the phone doesn't have GPS built in to it…

Jul 20, 2024 8:36 AM in response to MarquelleDavianMcKean

How calorie burn is actually calculated in general is by your heart rate, meaning you don’t necessarily have to walk or run to burn calories. The heart is like the engine and fat or carbs is its fuel. The iPhone or watch may lack an accurate gps speed or distance calculation because of the devices requiring a phone plan to access the satellites or towers. If they added something for checking distance or speed by satellite or tower then they may as well create a new phone/internet network.


Maybe they don’t have an accurate speedometer in the devices, how a speedometer works is there’s something heavy inside that slides back when accelerating and it moves a dial or something moving a bar or needle to the current speed.


In devices that lack a fixed position like in a car dashboard it could be hard to accurately calculate speed. Also walking on a treadmill is different than walking in the real world. The real world isn’t perfectly flare and doesn’t accelerate you, you have to fight gravity yourself. Sometimes I just measured a distance on maps and then time myself walking it to calculate my average speed, and I wouldn’t cut any corners.


So the Apple Watch has a heart beat detector and calculates speed, distance, and calculates calorie burn out of 2 or 3 of them. So the iPhone wouldn’t be as accurate since it lacked the heart beat sensor.


What if it does or did calculate the distance based on your heart beat, speed, or calorie burn.


Another thing is when checking heart beat you’d probably check it on the side of the lower neck just before it meets the collar bone or the underside of the wrist.


So you’d think it over estimated calorie burn and distance traveled. So maybe Apple decided to underestimate it so you for sure got a whole work out in. Also your brain uses energy, like if you did a whole bunch of computer work without eating you should still burn body fat, but maybe not.


So they may need to track you by satellite to check your speed with a laser or motion detection camera. Then again maybe your arms move faster than your legs and you may be holding the phone. As Apple users you can really say that you walk real or long miles. Lol


Health is weird, with being overweight you may not need to do any exercise to try and burn it. There’s different food ingredients like or similar to cholesterol and bacteria used like yeast enzyme. If you look at online diagrams of cholesterol, you’ll see that it’s only shown in the blood stream and in places like the gall bladder and liver. Probably because eating cheese in this large of a quantity or produced from yeast enzyme just came to exist in the last 20 years. Based on old diagrams and consumption amounts you’d assume the arteries would have to be completely clogged.


The bacteria was cultured to be used and the added fats may be synthetic or altered. For the fat to burn as energy like a carbohydrate there has to be a certain number of oxygen and hydrogen or nitrogen bonds, and a chemical reaction takes place.


Its fine to consume calories before walking/running and is completely necessary, if you have no actual body fat once your ATP is depleted your muscles and organs will start breaking down or downsizing because the body can’t support it.


Athletes or pro Olympic athletes and bodybuilders eat a lot of carbs or they can’t perform as well or even move. Everyone always drank a lot of soda unless they were athletes training, then it’s Gatorade or it’s bad for them, no fast food, no trans fat.


I’d suggest galactose and corn starch as an energy supplement. Another option is creatine but it can cause compartment syndrome in the legs.


I tricked myself for years by thinking I didn’t or couldn’t have diabetes and dropped my blood sugar from fasting and drinking water before doctor appointments. Insulin didn’t cure my issues, it just made me want more carbs, or kept me sitting down. I didn’t know that I was already more active than most people, anything more and I’d be considered athletic.


Diabetes wasn’t really that big of a deal and I assumed that every American probably had it.


What Im trying to say is that we didn’t take the calorie burn devices that seriously since they existed and the Apple Watch or health app may be completely accurate or underestimated for that reason, so you do more instead of less.


If you know the distance you travel and how long it takes then you can calculate your speed, and then you calculate how many calories you burn, but with devices like the Apple Watch or phones you may want to keep track of your unintentional exercise you do each day. The thing is if you don’t get your heart rate up high enough then you may not burn any calories or only burn the regular amount of being stagnant. People really liked keeping track of their daily steps but the Apple health app may be designed for intense exercise.

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iPhone Health app severely undercounts distance?

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