Aging Pace: what that gap means in speed

Sleep Age tells you how far your current sleep is from your actual age.

Aging Pace turns that gap into a speed: at this state, is your Sleep Age clock running faster or slower than the calendar?

What it means

If your Sleep Age is 3 years older than your actual age, those 3 years aren't just a number. They correspond to a faster clock. Aging Pace is that conversion:

• Within the normal range, your clock runs roughly with the calendar
• Sleep Age younger than your actual age: your clock runs slower
• Sleep Age older than your actual age: your clock runs faster

So it doesn't answer how many years apart you are. It answers what that gap means in speed, and whether it's worth acting on.

What does 1.0x mean?

1.0x means your Sleep Age is changing at the same pace as the calendar. Over one year, your Sleep Age changes by about one year.

Below 1.0x, your clock runs slower than the calendar.

Above 1.0x, it runs faster.

For example, 1.03x means your Sleep Age is changing about 3% faster than the calendar, based on your current state.

When the card says "+45 min of aging a day," it's simply another way of expressing that rate. It doesn't mean you're literally aging 45 minutes more each day. It describes how quickly your Sleep Age is changing.

Why is the scale different for everyone?

A 5-year gap doesn't represent exactly the same speed at every age.

That's why Aging Pace isn't measured with one fixed scale for everyone. Your normal range is based on your age and sex.

The 0.9x, 1.0x and 1.1x marks are simply points on that personal scale. The range can be different from person to person.

When should you pay attention?

Aging Pace has three ranges:

Slower

Your Sleep Age is more than 2.5 years younger than your actual age.

Normal

Your Sleep Age is within 2.5 years of your actual age. There's no need to change your sleep just to push the number lower.

Faster

Your Sleep Age is more than 2.5 years older than your actual age.

Look at the range first, then the exact multiplier. The three ranges tell you whether there's something to pay attention to. The multiplier tells you how much the rate differs.

Why doesn't it change every day?

Aging Pace looks at your most recent 84 valid nights, or about 12 weeks.

The window rolls every night: the newest night comes in, and the oldest drops out. The number you see updates once a week.

So one bad night usually won't move it much. A meaningful change takes time, as your new sleep gradually replaces the older nights in the window.

The same goes for improvement. If you start sleeping more regularly, you won't see a big change the next day. Aging Pace describes a pattern over time, not what happened last night.

How to read it

Look at the range first. Inside Normal, 0.97x and 1.03x both call for nothing. This isn't a score where lower is always better.

Several weeks in Faster is what's worth acting on. That points to something systematic rather than normal variation. Open your contributing factors and see which of the four is widening the gap.

To see whether the gap itself is growing or shrinking, look at the week-over-week change next to your Sleep Age. Aging Pace describes how fast the current gap is, not which way it's moving.