Sleep++ : Introducing Readiness Score

Today I’m delighted to announce the release of Sleep++ version 4.5. This update adds a long requested feature, Readiness Score.

What is Readiness Score?

There are a number of dedicated fitness trackers that seek to provide you with an indication of how “rested” or “recovered” you are each night’s sleep. My goal is to bring this to automatic sleep tracking on the Apple Watch.

This score is based on three measurements that have been found to generally correlate with how restorative your sleep was:

  • Heart Rate Variability (HRV): This is a measurement of how consistently your heart is beating during periods of restful sleep. The less consistent each beat of your heart is, the better the indication that your body is restored. Highly consistent heart beats are often an indication that your body is still in a higher stress mode and thus unable to engage in repair and restoration. HRV is a highly personalized measure, so I establish your personal baseline for comparison.

  • Resting Heart Rate (RHR): This is a measurement of how often your heart is beating while you are in periods of restful sleep. The lower this value is the better it is an indication that you are in restorative sleep. Since your RHR will fluctuate with your fitness, as well as your nightly recovery, I compare your RHR to your 30 day moving average to allow it to adjust to your current fitness.

  • Restful Sleep Duration: This is simply the total amount that you sleep each night where you appear to be calm and restful. If you aren’t sleeping enough in a night you are unlikely to have given your body sufficient time to repair and restore itself. For Sleep++’s readiness score I compare your sleep duration against your nightly sleep goal to establish your baseline.

These three values are then combined into a single numerical score from 0 to 100. With 100 indicating that all three measures are pointing you towards a highly restorative night. And 0 indicating that your body appears to have been really struggling during the night. Additionally, each composite value, and its comparison to baseline, is shown for reference.

It is important to treat this value as an indicator and not a clinical measurement. While there is substantial research to indicate that these three factors generally correlate with your sleep performance, they can be impacted by a wide variety of factors that can reduce their precision. The idea here is to give you a general sense of how prepared your body is and for you to then use that to make healthy choices for your day.

Using your Readiness Score

I have found that generating this score is helpful to me in two main ways: identifying poor habits and regulating my daily exertion.

Identifying Poor Habits

In working with the beta testing group for this feature I heard from several users that this score helped them quantify the impact of certain habits on their night’s restoration. For example, I heard from several folks that they could clearly see a connection between drinking alcohol and a lowered readiness score the following day. Similarly, drinking caffeine or eating large meals right before bed can negatively impact your body’s ability to sleep effectively.

What you do with that impact is up to you, but it is often helpful and motivating to be able to see a numerical impact from a behavioral choice. The negative case is often the most pronounced, but I have also seen benefit from identifying positive habits as well. Where if I really try to setup a good nights sleep (consistent bedtime, reduce screens before sleep, dark room, etc) I can affect a positive change as well. Which is super encouraging.

Regulating your Daily Exertion

Your ability to engage in high intensity activity is meaningfully impacted by your previous night’s sleep. This can be with regards to exercise, adventure or just normal life. The more rested you are, the more strain and challenge you are capable of effectively undertaking.

What I have found is that my Readiness Score gives me a good indication on which days I should “crush it” at the gym and which days I should “back off.” If I try to really workout with intensity on a day with a super low score I am often frustrated with my ability to perform and have sometimes even found that I am more prone to injury. Conversely, when I have a day with a high Readiness Score it is an opportunity for me to try and really make the most of it and get some work done.

This regulation of your activity level has really helped me to keep a more consistent exercise regime where I don’t get frustrated by the off days as much, and really can make fitness gains on the good days.


Your readiness score is available immediately after each night’s data is analyzed. Simply tap in the top right corner, on the heart shaped icon.

I have found Readiness Score to be super helpful during its development, and I hope it will help you too. It has altered how I think about my sleep and fitness regime, and encouraged me to make meaningful changes to improve my health.

Sleep++ is free on the App Store.

David Smith

Wearing an Apple Watch in Glencoe

A little while back I wrote about how I wished there was an Apple Watch that got battery life similar to what an “adventure watch” could get. In my case I was comparing it to the Coros Apex Pro, which gets battery life that you measure in days, rather than hours.

Well, I just got back from a trip up to the highlands of Scotland where I went on a 3 day hiking & wild camping trip. This seemed like an excellent opportunity to put the new 45mm Series 7 Apple Watch through its paces and see how it performs as an adventure watch.

My hope going into this trip was that it would do reasonably well. While it only has a rated battery life of 7 hours for outdoor GPS workouts…these tests are performed with the screen’s super bright Always-On display active. I wondered if turning this off (via Theater Mode) would mean that it would be able to last significantly longer than what it was rated as. I also put the watch in Airplane Mode, in case that helped too.

The result was surprisingly solid. For a day where I tracked a 16mi hike over the course of 5½ hours, the watch only used around 27% of its battery. This was using the built-in workout app with route recording active. So it uses around 1.7%/mile. On my second day I put it in ‘Power Saving Workout’ mode, which doesn’t record heart rate data as quickly. This used 23% for a 14mi hike, or around 1.6%/mi…which was actually less of a difference that I’d have guessed. So I just left it in regular workout mode from then on.

For comparison the Coros watch I was wearing on my other wrist did the entire 3 days/45miles of the trip using only 20% of its battery (around 0.4%/mile) so still dramatically better.

What gives me some excitement about this experience is that it seems clear that an Apple Watch can already make a solid companion for a long backpacking trip. When I set off I was expecting to have to charge it completely every day, but in reality it is more like every third day. Which gets it under my threshold for consideration for use. Especially since bringing it means that I now have a fully programmable computer on my wrist.

For me this meant that I could write a watch app to display UK Ordnance Survey maps right on my wrist with live GPS and compass information. This made wayfinding way simpler and less cumbersome.

It is becoming clear to me that Apple has chosen to spend their battery budget on illuminating a power hungry Always-On display. This makes sense, and I love the display on the Series 7 in daily use—there is now hardly any difference between the ‘dimmed’ and ‘bright’ display modes. Delightfully, an unpublicized corollary to this is that if you turn off the display, the possible battery life is now massive.

David Smith

12 days, 13 hours, 37 minutes

12 days, 13 hours, 37 minutes was the time it took for me to run down the battery on a Coros Apex Pro that I’ve been wearing for the last two weeks. During that time, I wore it continuously and had it track:

  • my steps,
  • my active calories,
  • my exercise minutes,
  • my heart rate,
  • my sleep and,
  • 13 hours of GPS tracked outdoor walks/runs/hikes.

Since its introduction six years ago, I’ve worn an Apple Watch nearly every day. I’ve developed nearly a dozen apps for it. I have grown fond of its appearance on my wrist. I even spend most of each summer wearing two of them concurrently to test the watchOS betas. However, there are certain things that the Apple Watch is profoundly ill suited for, which is where this Coros adventure watch shows up.

I’m in the process of preparing for a backpacking trip and was evaluating my electronics options. Previously for my backpacking trips I’ve just worn a simple, G-shock style, digital watch. Something that tells me the time, but little else. But I do find it rather annoying to not get the health and workout metrics that I’m used to from years of wearing an Apple Watch. I especially miss getting a GPS track of where I’ve been for use in future planning.

For short day trips, the Apple Watch is great. It has done an admirable job tracking various hiking outings for me, and I love being able to see exactly where I went on those adventures.

But its battery life has never allowed for this to be practical for multi-day trips. It needs to be charged after around 7 hours of tracked hiking. Fine for a day trip, but when I head out to environments like this there aren’t an abundance of outlets to be found.

I could use a battery pack, but I’d prefer to keep weight to a minimum and also would prefer to reserve that for my iPhone and emergency satellite communicator- both of which being always charged serve important safety roles. Using precious battery for something that is more of a confection seems silly and potentially dangerous.

Which lead me to evaluate other options for my watch. I settled on the Coros brand because they seem to be widely regarded as having the best battery life. I also love the way their watches look. Though fashion is less of an issue when alone in the wilderness, it is refreshing to look at my wrist and see something fresh and new.

I’ve been nothing but impressed by this watch. It is fast and efficient at tracking activities. It has a wide range of watch faces. It is super durable and comfortable to wear.

For normal use and regular activity, its battery lasted nearly two weeks, which was a bit of a shock compared to my daily charging rituals for my Apple Watch. According to its specs it should be able to GPS track around 100 hours of hiking when in power saving mode; more than enough for my needs.

As good as the Coros is, wearing it made me long for Apple to start diversifying their Apple Watch line. The Apple Watch is familiar and deeply integrated with the iPhone. It provides a level of integration that no third-party watch can match. It is backed by the largest company in the world with a proven record of advancement over decades. But they simply don’t make a watch suitable for long, outdoor activities.

The Apple Watch simply does too much. It is essentially a small iPhone, incredibly capable of a mind-bendingly wide range of tasks. This flexibility is part of its charm, its appeal. But it is also necessarily a profound stumbling block for more specialized roles. It makes sense for their first product in this area to be flexible and adaptable, but now six years on can’t it spread out a bit?

They are making a watch for the common case right now. I wish they’d consider the special case too. Until then, I’ll be leaving my Apple Watch at home for my adventures.

David Smith

A Plain GMT Face

I’m a big fan of the GMT watch face added in watchOS 7. It perfectly balances beauty and utility. It lets me know at a glance what the time is on the east coast, without cluttering my wrist.

There is, however, something that really kinda annoyed me about the usual view of it. Usually it shows the abbreviation of the city you have selected for the bezel ring in the middle of the watch face. So in my case this typically said ‘NYC’. I can see why they do this, but it feels really unnecessary and ruins the aesthetic of the watch for me. I know it is New York because I set it to New York.

So I set out to see if I could fix this. The result (seen at the top of this article) looks so much better in my opinion. The process of achieving this, however, was a bit more involved than I would have guessed so I figured I share it here in case anyone else wanted to achieve the same look.

Step 1: Add the Location

The GMT face appears to show a predefined set of locations plus whatever you have added into Clock app on your iPhone. So the first thing you need to do is add the location you want to show there. To make it easier to find the right city later on you may want to add a second city in the same timezone as your target, even if it already exists.

Step 2: Change the City Abbreviation

Next you need to open the Apple Watch companion app on your iPhone. Scroll down to Clock, then scroll again until you see City Abbreviation. Then choose the city you want to change.

The resulting text field won’t accept an empty string, so instead you have to put in a space (“ “) character.

This setting doesn’t accept Emoji, but it does accept certain typographic characters. For example, you can set the “” as the abbreviation for a bit of a ‘monogram’ look.

Step 3: Choose the new city

Now tap on your GMT watch face’s center and you’ll be shown an array of options. Scroll with the Digital Crown until your desired location shows up. As it has no name this can be a bit tricky, and so I that’s why in Step 1 I recommended adding a second city so that you can find that one, and then choose the blank with the same time.

You’re all set.

David Smith

Pedometer++ Complications Overhaul

I just released Pedometer++ 4.7. This update dramatically expands the complications provided for your Apple Watch. You can now precisely choose how you’d like your daily step count to be displayed on your wrist.

You can choose between:

  • simple numerical counts of your steps, distance or floors,
  • goal progress rings,
  • detailed graphs,
  • or a simple icon.

All of these update throughout the day to let you know if you are on track with your goals.

Full Complication Options

Graphic Circular

Graphic Large

Graphic Bezel

Graphic Corner

Graphic Extra Large

Utility Corner

Utility Wide

Modular Large

Modular Small

David Smith