coffee

Brewed Coffee (240ml / 8oz)

Caffeine Half-Life Analysis

For: Elderly (65+)
95
mg Caffeine
6.5
Hour Half-Life
~N/A
Hours to Sleep-Safe
300
mg Daily Limit

trending_down Caffeine Decay Timeline

How 95mg caffeine clears from your system with a 6.5-hour half-life

Time Elapsed Caffeine Remaining % of Original Status
Now (consumption) 95.0 mg
100.0% 		Moderate
After 1 hour 85.4 mg
89.9% 		Moderate
After 2 hours 76.8 mg
80.8% 		Moderate
After 3 hours 69.0 mg
72.6% 		Moderate
After 4 hours 62.0 mg
65.3% 		Moderate
After 5 hours 55.7 mg
58.7% 		Moderate
After 6 hours 50.1 mg
52.7% 		Moderate
After 8 hours 40.5 mg
42.6% 		Minimal
After 10 hours 32.7 mg
34.4% 		Minimal
After 12 hours 26.4 mg
27.8% 		Minimal
After 16 hours 17.2 mg
18.2% 		Minimal
After 20 hours 11.3 mg
11.9% 		Minimal
After 24 hours 7.3 mg
7.7% 		Cleared

health_and_safety Health Insights for Elderly (65+)

⚠️ Important Health Consideration

After age 65, liver enzyme efficiency decreases, extending caffeine's half-life. Sensitivity to caffeine's effects on sleep also increases.

Daily Limit Calculation

  • • Recommended daily limit: 400mg of caffeine
  • • Caffeine per serving: 95mg
  • • Servings until limit: 4.2 servings

Avoid caffeine after midday. Consider reducing total intake as sensitivity increases.

Sleep Quality Impact

Caffeine blocks adenosine receptors in the brain, preventing the buildup of sleep pressure. Even when you don't feel "wired," residual caffeine can reduce deep sleep quality by up to 20%.

>100mg
May disrupt sleep
50-100mg
Reduced deep sleep
<50mg
Minimal impact

science How Caffeine Half-Life Works

Half-life is the time required for the body to eliminate 50% of a substance. For caffeine, this primarily occurs in the liver through the CYP1A2 enzyme system.

With a half-life of 6.5 hours for elderly (65+), caffeine follows exponential decay:

  • After 6.5 hours: 50% remains (47.5mg)
  • After 13.0 hours: 25% remains (23.75mg)
  • After 19.5 hours: 12.5% remains (11.875mg)
  • After 26.0 hours: 6.25% remains (5.9375mg)

The elderly (65+) category has a slower metabolism compared to healthy adults (5 hours baseline). After age 65, liver enzyme efficiency decreases, extending caffeine's half-life. Sensitivity to caffeine's effects on sleep also increases.

warning Please Note

Avoid caffeine after midday. Consider reducing total intake as sensitivity increases.

Compare Other Drinks

Espresso (30ml / 1oz shot) 63mg Red Bull (250ml / 8.4oz) 80mg Monster Energy (473ml / 16oz) 160mg Green Tea (240ml / 8oz) 28mg

Compare Conditions

Healthy Adult 5.0h Smokers 3.0h Pregnancy 10.5h Birth Control Users 7.5h Liver Impairment 12.0h Fast Metabolizers (Genetic) 3.5h

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About Brewed Coffee (240ml / 8oz)

Standard drip-brewed coffee

Note: Caffeine can range from 70-140mg depending on brewing method and bean origin

help Frequently Asked Questions

How long does Brewed Coffee (240ml / 8oz) caffeine last for elderly (65+)?

For elderly (65+), the caffeine half-life is approximately 6.5 hours. This means that 95mg of caffeine from Brewed Coffee (240ml / 8oz) will take about 6.5 hours to reduce to 48mg, and 13.0 hours to drop to 24mg. Full clearance (below 10mg) takes approximately 21.1 hours.

When should I stop drinking Brewed Coffee (240ml / 8oz) to sleep well?

If you plan to sleep at 10 PM, you should consume your last Brewed Coffee (240ml / 8oz) by any time - caffeine level is low. This allows approximately sufficient hours for caffeine levels to drop below the sleep disruption threshold of 100mg.

How does being in the 'Elderly (65+)' category affect caffeine metabolism?

After age 65, liver enzyme efficiency decreases, extending caffeine's half-life. Sensitivity to caffeine's effects on sleep also increases. Avoid caffeine after midday. Consider reducing total intake as sensitivity increases.