How to Track Sleep & Metabolic Health

Wearables can produce hundreds of data points, but only a handful truly matter for insulin sensitivity, liver repair, cortisol regulation, and metabolic recovery.

Below is the Metabolic Metrics Shortlist — the specific numbers that are meaningful.

1. Total Sleep Time (Goal: 7–9 hours)

Yes, we start simple.

Why it matters metabolically:

< 6 hours = 30–60% reduction in insulin sensitivity next day
< 5 hours = elevated cortisol + increased blood glucose
8 hours = peak glucose handling / lowest cravings

This is the baseline requirement for metabolic repair.

Apple Watch + Oura can both track this reliably.

2. Deep Sleep (Oura) or Core Sleep (Apple Watch)

Target: 1.5–2.5 hours per night

Deep sleep is where:

liver detox
mitochondrial repair
fat oxidation
growth hormone
muscle recovery
mineral balancing

ALL happen.

Deep sleep is metabolic sleep.

Elevation of:

ALT
AST
triglycerides
fasting glucose

are strongly correlated with low deep sleep.

Most adults get less than 60–90 minutes — TOO LOW.

If you fix ONE number, fix this one.

3. REM Sleep (Target: 1.5–2.5 hours)

REM sleep is where:

cortisol resets
emotional regulation
nervous system recovery
cravings decrease
stress eating reduces

Low REM = high cortisol next day.

This is where 2–3 AM awakenings show up in the data.

Red flag REM patterns:

short first REM cycle
waking before REM begins
REM compressed at the end of the night

These correlate strongly with:

cortisol spikes
histamine elevations
gut issues

Resting Heart Rate (RHR)

Target: < 60 beats per minute (ideally 50–55 for metabolic excellence)

Why it matters: High RHR at night = nighttime cortisol and poor insulin regulation.

If RHR stays elevated in the first half of the night, it means:

room too warm
ate too late
alcohol
high histamine
stress hormones
blood sugar dysregulation

This is a CORE metabolic indicator.

Heart Rate Variability (HRV)

Target varies by age, but generally:

Women 50–65: 25–60 ms is typical
Metabolically healthy 50–65: 60–120 ms

HRV is a metabolic super-metric. High HRV = parasympathetic dominance (rest & repair mode)

Low HRV = sympathetic dominance (stress mode)

Low HRV correlates with:

insulin resistance
fatty liver
chronic inflammation
poor glucose tolerance
metabolic syndrome

You should track trends, not day-to-day.

Body Temperature (Nighttime Temp Trend)

Oura measures this beautifully. Apple is adding temperature trends, too.

Why Temp Matters:

Nighttime temperature changes correlate with:

cortisol
histamine
ovulatory cycle
inflammation
metabolic distress

Red flag:

If body temp:

rises after bedtime → metabolic disruption (often eating too late)
fluctuates a lot → inflammation/infection/stress

Metabolic repair requires a stable, low nighttime temperature.

7. Sleeping Heart Rate “dip.”

Ideal pattern:

RHR should drop 10–20% within 60–90 minutes of sleep.

Meaning:

calm nervous system
low insulin
melatonin dominance
liver repair happening

Red flag:

If RHR stays high for 2–3 hours, it means:

late meal
alcohol
high cortisol
room too warm
light exposure at night

This one metric alone can dramatically fix sleep quality.

Latency (time to fall asleep)

Target: 10–20 minutes

Shorter = stress/exhaustion
Longer = cortisol too high

If you consistently take >30 minutes to fall asleep, that is cortisol, not “bad sleep habits.”

Wearables track this well.

Wake After Sleep Onset (WASO)

Target: < 45 minutes total

WASO is a massive metabolic marker because:

Blood glucose dips
Cortisol spikes
Nighttime liver fat storage increases

2–4 AM wakings show up HERE.

Your pattern. Your audience’s pattern. Classic metabolic dysfunction sign.

Sleep Timing Consistency

Goal: Bed and wake time within 60 minutes daily

This affects:

insulin sensitivity
lipid metabolism
ghrelin and leptin
fasting glucose

Consistency > duration.

This is circadian medicine.

Metrics That DON’T Matter (Ignore these)

Sleep “scores” (arbitrary)
Movement-based sleep staging “accuracy.”
“Calorie burn” at night
“Sleep stages percent” alone

Always track trends over weeks, not individual nights.

The Metabolic Sleep Dashboard (Summary)

Here’s the simple daily checklist:

From Oura / Apple Watch:

Total Sleep: > 7 hours
Deep Sleep: > 90 min
REM Sleep: > 90 min
Resting HR: < 60
HRV Trend: rising
Temp: stable low
RHR dip within 60–90 minutes
WASO: < 45 minutes
Latency: 10–20 minutes
Bedtime/Wake consistency: ± 1 hour

If you hit 6 out of 10, you are doing extremely well metabolically.

If you hit 8 or more, liver fat reduction is happening.

Aware Trade