6 KPIs Your Apple Watch is Telling You

I’ve worn an Apple iWatch (Model 6) everyday for over 3 years now.

As I’ve mentioned numerous times before, you can’t improve what you don’t measure.

Here are the 6 important metrics from my Apple Watch that you can monitor to ensure your training is at optimal performance (I’m sure Android watches have similar features):

Workout

Max HR

Forget the 220 – Age = MaxHR formula. If you use it, it’s probably +/- 10%, if not higher. This formula sort of works when you are 25 or 30 years old. But a better formula is:

MaxHR = 211 – (0.64 x Age)

At my age (61), that number is either 159 (old method) or 172 (new method), but I have had workouts where it reaches 180+. I even wore my watch (by accident) in a 400m race last summer:

Cardio Fitness (or METS)

They say VO2Max is the greatest KPI for longevity (notably, from Dr. Peter Attia). And that the Norwegian 4×4 workout is the best way to increase VO2Max. I’m a sprinter, so this number doesn’t mean much to me (Oh, Vienna), but it does tell me how much effort I am using for a “20 min long run” or my “10 min jog” before my workout.

The Norwegian 4×4 workout: is a high-intensity interval training (HIIT) method that involves four, 4-minute intervals of high-intensity exercise at 85-95% of your maximum Heart Rate, followed by three minutes of active recovery such as walking.

On your iPhone, you have to go to the specific workout, and click details to see your METS as well as other measurements.

Remember 1 MET = 3.5 mL/kg/min, or milliliters of oxygen consumed per kilogram of body weight per minute (mL/kg/min)

If my VO2Max is 35 mL/kg/min, and my 4 lap, 8 minute min easy jog is 10 METs, that’s that same thing!

HR Post Recovery

Some people measure heart rate 1 Minute after your workout (post-workout), but the watch shows a graphic of each minute (1-2-3) with a number displayed for 3 minutes.

For sprinters, this is key, as if you are doing repeat short runs (either blocks, or flys of 10m, for example), how much rest do you take? Ideally 5 minutes for a “full recovery”, but the watch says you can go after 3 minutes.

It takes approximately 3 minutes to replenish our body’s stores of ATP and PC, in order for the ATP/PC system to be the predominant system used in the next 7 seconds of exercise. Hence, another reason to go hard for the 1st 7 seconds of your 400m (i.e. first 50-60m meters, 40m for Masters). Use up this energy source, because you won’t get it back later in the race!

The 3-minutes-between-reps is also good for plyometrics, for example, Speed Bounds (10m run in, then 30m straight-leg or bent knees bounds). Speed Bounds are quite taxing on the CNS, joints, and tendons so be sure to be nearly recovered before each rep.

Starting Block Tip: If your right foot is the back block, then wear a watch on your left hand. Why? Because your hands should move a fraction before your feet, based on neurology. (we’re talking fractions faster!). So react to the gun, not listen to the gun, and explode with the left hand with the watch. Your feet will follow, trust me!

Rest & Sleep

Resting HR

This is a key metric to see how you are feeling the day of the workout. If it’s higher than normal, then perhaps you should back off a bit. My biggest problem the first hour upon waking is the aches & stiffness to my tendons & muscles. Most minor annoyances disappear after 1 hour. Then again, most minor annoyances disappear after my coffee :)

But I have noticed my resting HR is higher in very warm temperatures (i.e. Paris in summer with no air conditioning!). Again, something to monitor, but don’t obsess with it.

Sleep Hours & Deep Sleep

Wearing the watch won’t help you sleep more, or get better sleep, but it does keep you honest and aware that sleep is probably the best form of recovery. How many hours you sleep, as well as the quality of sleep (i.e. waking up, or restlessness, as seen in the orange segments) is shown on the chart.

In addition, it shows the amount of Deep Sleep (as seen in the dark blue segments)

I try to aim for 9 hours of sleep, and 60 min of deep sleep, but I rarely get this. Sleep is also where HGH & Testosterone is being released. Did I mention sleep is one of the best forms of recovery?

If you must sleep 4 hours because of an early flight, then I find the deep sleep is not affected, which is good! But I still feel like crap. One-offs are okay in life, just deal with it.

Before sleeping, be sure you set your watch on DND (do not disturb) or Focus mode (the icon of a moon sliver), and turn off display or Theater Mode (the icon with two face masks).

Lowest HR during sleep

This number should be a bit lower than your Resting HR. It’s also an indicator of how well you slept. Again, this can be affected by excessive heat, which is why they prescribe the best sleep happens in a cool, dark place. It’s all about temperature & exposure to blue light!

Honourable Mention

HRV

I won’t get into this topic, but I don’t think the watch can accurately measure this. Maybe later models have improved (I have the model 6). Let me know in the comments.

But I do believe there is a correlation between heart/nerve, breathing techniques, the Vagus nerve, and lowering HR to calm pre-race jitters. This topic(s) have been covered in a variety of articles, which I can update & consolidate if there is a demand for this information.

More on Rest & Recovery

Be sure to check out this presentation from 2022:

Link: https://www.youtube.com/watch?v=_FAdMoXbkas