Caffeine doses as low as 100 mg could reduce deep sleep quality

• A recent review has found that even low doses of caffeine may affect sleep quality, particularly slow-wave (deep) sleep.
• While caffeine consumed closer to bedtime has a stronger impact, consuming caffeine in the morning may still reduce sleep, the researchers found.
• Experts advise that genetics, age, and metabolism may also influence how caffeine affects sleep, so there’s no universal cutoff time.

Caffeine is generally associated with increased alertness while awake, but its effects may persist while sleeping.

Caffeine affects adenosine signaling, which is vital in regulating the sleep-wake cycle. Now, researchers are investigating whether caffeine consumption impacts the brain during sleep.

A systematic review published in Nutrients assessed the effect of caffeine on sleep-related electroencephalography (EEG), a test that records the electrical activity in the brain. In particular, they looked at how caffeine might affect low-frequency brain waves associated with deep sleep.

Deep sleep occurs during the third stage of non-rapid eye movement (NREM) sleep. It is essential for repairing and restoring the body.

The researchers found that caffeine consumption could negatively impact the quality of deep sleep, potentially reducing the body’s ability to repair itself during this time.