iOS 11 brings a major change to how Apple handles your Health data, and makes it easier for users to save it.

Over the past few years, the Health app — and all the fitness data within — has become more and more important to everyday iPhone users. If you have an Apple Watch, you'll have months (and possibly years) of heartbeat and activity information in there, along with any app-submitted data, sleep tracking, step-tracking, and more.

Backing up that data is important from a preservation aspect — you don't want to lose it — but Apple also cares about keeping it safe from prying eyes. It's why, when the feature first debuted, the company limited it to a password-required encrypted iTunes backup.

As Apple's cloud-side encryption has gotten better, the company has allowed users to back up via iCloud as well as iTunes; now with iOS 11, you can not only back up your Health data, but actively sync it with iCloud, too.

How Health iCloud syncing is different from a backup

When you back up your iPhone via iCloud, you make an (ideally) nightly backup of everything your phone has recorded since your last backup. That includes contacts, Health data, email messages, apps and their home screen positioning, and more. The information in this backup is only available to your current device or when you restore a new device with the backup, however.

In contrast, iCloud sync happens whenever you're connected to the internet, and syncs to any device logged into your iCloud account. We already use it to sync things like keychain passwords, Apple Notes, Safari bookmarks, HomeKit preferences, non-credit card Wallet passes, Calendar info, and the like. All of these options can be enabled or disabled on a feature-by-feature basis from the iCloud screen in your Settings app on each device.

With iOS 11, users now have a Health toggle in the iCloud settings screen that they can enable or disable. Whenever the toggle is enabled, Apple uploads an encrypted package of your latest Health data, which then automatically syncs with any other iOS devices logged in to your iCloud account.

What iCloud syncs from your Health repository

  • Health data (heart rate information, sleep tracking, step counts, elevation, etc)
  • Sources and connected devices
  • Medical ID
  • Activity Rings
  • Workouts
  • Stand Hours

I'm not sure yet whether Health syncs your Activity achievements, but I'm looking into it.

Why should I use Health iCloud sync instead of a backup?

In short, iCloud sync keeps your Health data backed up across devices, rather than limiting it to a single iPhone; if you forget to back up your iPhone for a week and then drown it on a camping trip, you'd lose all of that health data. In contrast, as long as you had iCloud sync enabled and some form of internet, you'd still have all that data ready to sync to a new iPhone when you got home.

The other big reason for using iCloud sync: It lets you move your health and activity data without having to restore a device from backup. It's a big win for the clean install iPhone crowd, but it's also nice for folks like me, who frequently test multiple devices — and multiple Apple Watches — and have lost data in the past because I could only sync my Health data to one repository.

And, like iCloud Keychain and Messages, your Health data is completely encrypted: Apple can't see if you missed your Activity goal for the day, nor does the company really want to. (That's what the Apple Watch guilt-trip notifications are for.)

Why shouldn't I use iCloud sync for Health?

I'm pretty excited about iCloud sync for Health, but there are a couple of edge-case issues where you wouldn't want to immediately enable it in iOS 11.

You use one iCloud ID for an entire family

First of all, please don't do this. Instead, create a Family Sharing account and make separate IDs for your family. iCloud has too much individual data at this point to make sense of sharing an individual account.

But that said, if you're hellbent on sharing the same account for multiple people, each person's Health data from their respective device is going to get smushed together and look really weird.

You still have a bunch of devices on iOS 10, including the one synced with your Apple Watch

Your Health data won't sync to iOS 10 devices, so you don't want to set up iCloud Health sync if you won't actually get to take advantage of it.

You're concerned about the security of your Health data

While this is an entirely valid concern, Apple's security system has never been broken, and its multi-key encryption system would require a potential hacker to have physical access to your phone to decrypt your data (in addition to breaking Apple's private keys). Apple will likely have more information on how this works in its iOS security guide, which the company updates every year, but if you're still concerned about the safety of your data, you can always make encrypted backups to iTunes instead.

How to set up iCloud sync for Health on your iPhone

Setting up health syncing on your iPhone is pretty straightforward once you're running iOS 11.

  1. Launch the Settings app.
  2. Tap the Apple ID banner at the top of the screen.
  3. Tap iCloud.
  4. Tap the toggle next to Health to enable it.

One big note: If you plan to move to a new iPhone without restoring from backup, make absolutely sure your old iPhone has the Health toggle turned on and has synced. Otherwise, you risk not having your Health data transfer over.

Other questions about Health syncing in iOS 11?

Let me know below!