How to calculate sleep efficiency
The Sleep Efficiency Formula
The formula for calculating sleep efficiency is:
Sleep Efficiency = (Actual Sleep Time ÷ Total Time in Bed) × 100%
This formula reflects the proportion of time you actually spent asleep while in bed. The higher the percentage, the better your sleep quality.
Example: If you lie in bed for 8 hours but actually sleep for 6 hours, your sleep efficiency is 75%.
Components of Sleep Efficiency
1. Total Time in Bed
This refers to the total duration from getting into bed to prepare for sleep until getting out of bed.
Example: If you lie down at 11:00 PM and get up at 7:00 AM, your total time in bed is 8 hours.
2. Actual Sleep Duration
This is the time when you are truly asleep, after deducting time spent awake due to difficulties falling asleep, waking up during the night, etc.
Example: If you fall asleep 30 minutes after lying down and wake up twice during the night for a total of 1 hour, your actual sleep duration = 8 hours - (0.5 hours + 1 hour) = 6.5 hours.
Factors Affecting Sleep Efficiency
1. Difficulty Falling Asleep
If you cannot fall asleep within 30 minutes after lying down, your actual sleep time will be directly reduced.
2. Frequent Awakenings During the Night
Sleep is disrupted due to:
- Environmental disturbances (noise, light)
- Physical discomfort (nocturia, temperature)
- Stress or anxiety
3. Irregular Sleep Schedule
Staying up late or catching up on sleep during the day can disrupt your biological clock and reduce sleep efficiency.
The Significance of Sleep Efficiency
Assessing Sleep Quality
- ≥85% efficiency is generally considered normal
- Below 80% efficiency may indicate sleep issues
- 90%+ efficiency indicates excellent sleep quality
Adjusting Sleep Habits
Reduce ineffective lying in bed by optimizing the relationship between bedtime and actual sleep time.
Practical Suggestions for Improving Sleep Efficiency
1. Stick to a Fixed Routine
Go to bed and get up at the same time every day to strengthen your biological clock regularity.
2. Reduce Ineffective Bed Rest
If you cannot fall asleep after lying in bed for 20 minutes, get up and relax to avoid prolonging wakefulness due to anxiety.
3. Optimize Your Sleeping Environment
- Keep the bedroom dark and quiet
- Control room temperature at 18-22°C
- Ensure mattress and pillow are moderately soft and hard
4. Relax Your Body and Mind
- Avoid electronic screens 1 hour before bedtime
- Relieve stress through meditation, reading, or listening to soft music
5. Limit Daytime Naps
Take a nap of no more than 30 minutes during the day to avoid affecting nighttime sleep drive.