Understanding Sleep Phases: Light, Deep, REM
schlaf

Understanding Sleep Phases: Light, Deep, REM

7 minFebruary 14, 2026

Introduction

Every night your body runs a fascinating program: 4-6 sleep cycles of about 90 minutes each, alternating between light sleep, deep sleep, and REM sleep. Each phase has a specific function — and when one is disrupted, you feel it the next day.

Light Sleep (N1 & N2): The Transition

Light sleep makes up about 50% of your sleep time. In phase N1 you drift from waking to sleeping. In N2 your brain begins transferring short-term memories to long-term storage.

**Why it matters:** Without enough N2 sleep, your memory suffers. If you're studying for an exam, good N2 sleep is crucial.

Deep Sleep (N3): The Repair Shop

Deep sleep is the most valuable phase — this is where real recovery happens. Growth hormone is released, cells are repaired, the immune system is strengthened. It makes up 15-25% and mostly occurs in the first half of the night.

**Why it matters:** Without enough deep sleep, your body can't recover from exercise, infections, or stress.

REM Sleep: The Dream Factory

In REM sleep your brain is almost as active as when awake, processing emotions and sorting learned information. REM makes up 20-25% and increases in the second half of the night.

**Why it matters:** REM deficiency leads to emotional instability, concentration problems, and is linked to depression. Alcohol reduces REM sleep by up to 40%.

Conclusion: Optimize Your Sleep Phases

You can't directly control your sleep phases, but you can create conditions for them to run optimally.

**Track your sleep with BESTBUDDY** and see after one week how your habits affect duration and quality.

FAQ

Was ist REM-Schlaf?

REM steht für Rapid Eye Movement. Deine Augen bewegen sich schnell, du träumst intensiv und dein Gehirn verarbeitet Emotionen und Gelerntes. Es ist essentiell für mentale Gesundheit.

Wie viel Tiefschlaf brauche ich?

Idealerweise 1.5-2 Stunden pro Nacht. Tiefschlaf nimmt mit dem Alter natürlicherweise ab — umso wichtiger sind gute Schlafbedingungen.

Warum wache ich nachts auf?

Zwischen Schlafzyklen (alle 90 Min) wacht man kurz auf — das ist völlig normal und meist unbewusst. Problematisch wird es erst wenn man nicht wieder einschlafen kann.

Kann ich mehr Tiefschlaf bekommen?

Ja: Regelmässiger Sport, kühles Schlafzimmer (16-18°C), Alkoholverzicht und eine feste Schlafenszeit fördern Tiefschlaf nachweislich.

Beeinflusst Koffein die Schlafphasen?

Ja, Koffein blockiert Adenosin-Rezeptoren und reduziert den Tiefschlaf-Anteil — selbst wenn du damit einschlafen kannst.