Sleep Cycle Planner & Clinical eGFR (2021 CKD-EPI) Reference Calculator: Interactive Graph & Formula

Optimal Bedtimes (5–6 Sleep Cycles) & 2021 CKD-EPI eGFR

Bedtime: 23:15 or 21:45 • eGFR: 103.8

For 07:00 wake-up (includes 15m sleep latency) • eGFR in mL/min/1.73m²

5 Sleep Cycles (7.5 hrs sleep) Bed at 23:15

6 Sleep Cycles (9.0 hrs sleep) Bed at 21:45

CKD-EPI 2021 eGFR 103.8 mL/min/1.73m²

Serum Creatinine Input 0.95 mg/dL

Inputs

Target Wake-Up Hour (0–23h Clock) hour (24h)

Desired wake-up time (e.g. 7 for 07:00 AM, 6.5 for 06:30 AM).

Serum Creatinine (SCr) mg/dL

Blood creatinine level in mg/dL from laboratory panel.

Adult Age years

Adult age (18+ years) for CKD-EPI equation.

Sex Reference Constant (CKD-EPI)

Select 2021 CKD-EPI creatinine reference parameters.

Results & Graph

Optimal Bedtimes (5–6 Sleep Cycles) & 2021 CKD-EPI eGFR

Bedtime: 23:15 or 21:45 • eGFR: 103.8

For 07:00 wake-up (includes 15m sleep latency) • eGFR in mL/min/1.73m²

5 Sleep Cycles (7.5 hrs sleep)

Bed at 23:15

6 Sleep Cycles (9.0 hrs sleep)

Bed at 21:45

CKD-EPI 2021 eGFR

103.8 mL/min/1.73m²

G1 Normal/High (≥90)

Serum Creatinine Input

0.95 mg/dL

Sleep Duration by Ultradian Cycle Count (Minutes)

4 Cycles (6.0 hrs) vs. 5 Cycles (7.5 hrs) vs. 6 Cycles (9.0 hrs)

Graph 1 • Nocturnal 90-Minute Sleep Cycle Milestones (4, 5 & 6 Cycles) Waking at the end of a 90-min REM cycle reduces grogginess

Graph 2 • KDIGO 2021 CKD-EPI Kidney Function Stage Spectrum Race-free 2021 NKF-ASN creatinine equation

Graph 3 • Projected eGFR Trajectory Across Age (mL/min/1.73m²) Models physiological age factor (0.9938^Age) at constant creatinine

Summary: Optimal bedtimes for a 7:00 wake-up are 23:15 and 21:45; eGFR is 103.8 mL/min/1.73m².

Summary: To wake up refreshed at 07:00 at the end of a 90-minute ultradian sleep cycle (allowing 15 minutes to fall asleep), aim to be in bed by 23:15 (5 cycles = 7.5 hrs) or 21:45 (6 cycles = 9.0 hrs). Using the 2021 race-free CKD-EPI equation for a 40-year-old male with 0.95 mg/dL serum creatinine, estimated GFR is 103.8 mL/min/1.73m².

⚠️ Medical & Safety Disclaimer: The 2021 CKD-EPI eGFR calculation is for informational reference only and must be interpreted by a nephrologist or physician alongside lab reference ranges. Never use any online estimator to judge fitness to drive after consuming alcohol.

⚡ Send result to: BMI →Calorie & TDEE →Age Calculator →

Interactive chart & math engine powered by CalculatorGraph

Formula & Mathematical Methodology: 90-Minute Ultradian Sleep Cycle & 2021 CKD-EPI Creatinine Equation

eGFR = 142 \times (min (SCr κ, 1)) α \times (max (SCr κ, 1)) -1.200 \times 0.9938 Age

$90 min$ : Average duration of one complete NREM + REM ultradian sleep cycle
$SCr, κ, α$ : Serum creatinine (mg/dL) and sex-specific spline knots in the 2021 CKD-EPI formula

Rounding: Clock times round to nearest minute; eGFR rounds to 1 decimal place.

Worked Example: 07:00 Wake-Up Time & 40-Year-Old Male with 0.95 mg/dL Serum Creatinine

Find 5- and 6-cycle bedtimes for 07:00 AM and compute 2021 CKD-EPI eGFR.

5 cycles (450m) + 15m sleep onset = 465m before 07:00 → 23:15 bedtime.
6 cycles (540m) + 15m sleep onset = 555m before 07:00 → 21:45 bedtime.
2021 CKD-EPI eGFR = 142 × (0.95/0.9)^(−1.200) × (0.9938)^40 = 103.5 mL/min/1.73m².

Result: Bedtimes are 23:15 (7.5h) or 21:45 (9.0h); eGFR is 103.5 mL/min/1.73m².

Frequently Asked Questions

Why does waking up between 90-minute cycles feel easier than waking during deep slow-wave sleep?

At the end of each ~90-minute cycle, the brain transitions into lighter sleep stages near REM, reducing grogginess (sleep inertia) when your alarm sounds.

Health & Fitness · Sleep Science & Clinical Equations

Sleep Cycle Planner & Clinical eGFR (2021 CKD-EPI) Reference Calculator: inputs, method, and how to read the result

Plan 5-cycle (7.5 hr) and 6-cycle (9.0 hr) bedtimes and compute 2021 CKD-EPI eGFR from serum creatinine.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

Target Wake-Up Hour (0–23h Clock): Desired wake-up time (e.g. 7 for 07:00 AM, 6.5 for 06:30 AM).
Serum Creatinine (SCr): Blood creatinine level in mg/dL from laboratory panel.
Adult Age: Adult age (18+ years) for CKD-EPI equation.
Sex Reference Constant (CKD-EPI): Select 2021 CKD-EPI creatinine reference parameters.

What the calculation includes

With the default values shown, Optimal Bedtimes (5–6 Sleep Cycles) & 2021 CKD-EPI eGFR is Bedtime: 23:15 or 21:45 • eGFR: 103.8. The calculation follows 90-Minute Ultradian Sleep Cycle & 2021 CKD-EPI Creatinine Equation; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Target Wake-Up Hour (0–23h Clock) from 7 hour (24h) to 8 hour (24h) changes Optimal Bedtimes (5–6 Sleep Cycles) & 2021 CKD-EPI eGFR from Bedtime: 23:15 or 21:45 • eGFR: 103.8 to Bedtime: 00:15 or 22:45 • eGFR: 103.8. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

Includes a 15-minute average sleep onset latency buffer.
eGFR is an estimate for stable adult outpatients and is not diagnostic without clinical evaluation and urine albumin-to-creatinine ratio (uACR).

Scope: Global Clinical & Sleep Reference Check the assumptions and limitations against your situation before relying on the estimate.

More in Health & Fitness: BMI Calculator (Body Mass Index), Calorie Needs & TDEE Calculator, Age Calculator.