The Physiology of Tahajjud: Why the Last Third of the Night Feels Different

Many people describe a quiet clarity that appears late at night or just before dawn. The mind feels calmer. Distractions fall away. Thoughts feel more organised. Reflection comes more easily.

In Islam, this time is known as the last third of the night, and it is when tahajjud and qiyam are performed. For Muslims, it is a time of prayer and du’a. What is remarkable is that modern physiology now helps explain why this window feels so different, regardless of belief.

This is not about spirituality alone. It is about timing, hormones, and the nervous system.

A Unique Biological Window

The human body follows a predictable rhythm across the night. Sleep is not one long, uniform state. It moves through cycles, each serving a different purpose.

By the final third of the night, several important shifts have already taken place.

Deep restorative sleep has largely occurred.
Melatonin, the sleep hormone, begins to taper.
The nervous system is calmer and less reactive.
Mental noise is reduced.

This creates a state that is neither fully asleep nor fully alert. It is a rare overlap of rest and awareness.

For Muslims, this is the moment encouraged for tahajjud. For non-Muslims, it is the same window where early risers often report their clearest thinking.

Cortisol Is Rising, But Gently

Cortisol is often misunderstood. It is not a stress hormone by default. It is a waking hormone.

In a healthy rhythm, cortisol begins to rise slowly in the final third of the night, preparing the body to wake. This rise is gentle, not sharp. It supports alertness without anxiety.

At this stage:

✅ focus improves
✅ memory access feels easier
✅ emotional reactivity is lower
✅ the mind feels quieter

This is why reflection, planning, prayer or journaling often feel easier at this time than later in the day.

The Nervous System Is Most Settled

During the day, the nervous system is constantly responding. Noise, light, conversation, decisions and movement all require energy.

By the final third of the night, stimulation has dropped away. The parasympathetic nervous system, responsible for calm and restoration, is dominant.

This state allows for:

✅ deeper emotional processing
✅ reduced defensive thinking
✅ greater sense of perspective
✅ calmer breathing and heart rate

In Islamic tradition, this calm is used for du’a and worship. Outside of that context, it is the same state many people seek through meditation or silence.

Why Intention Matters

The Prophet ﷺ did not encourage staying awake all night. He slept, then rose. This is important.

From a physiological perspective, the benefits of the last third of the night depend on having already rested. Skipping sleep to access this time removes much of its advantage.

The clarity comes from timing, not deprivation.

This is why sleeping earlier makes waking for tahajjud possible without strain. It also explains why people who sleep late often miss this window entirely.

Early Morning Barakah and Modern Science

The Prophet ﷺ spoke of barakah in the early morning hours. While barakah is a spiritual concept, its effects can be observed practically.

Early morning light resets circadian rhythm.
Hormones stabilise more easily.
Mood regulation improves.
Energy tends to be steadier across the day.

Modern research consistently shows that people who wake earlier, in alignment with natural light, often experience better sleep quality and emotional balance.

The barakah is not only spiritual. It is embodied.

Accessing the Benefits Without Religious Practice

For non-Muslims, the same physiological window can be accessed without prayer.

Quiet reflection.
Gentle stretching.
Journaling.
Breathwork.
Silent sitting.

What matters is the timing and the stillness, not the label.

The final third of the night offers a nervous system state that is difficult to replicate during daylight hours.

Why This Time Feels So Rare

Modern life works against this rhythm.

Late nights.
Artificial lighting.
Screens before bed.
Irregular sleep schedules.

All of these push sleep later and compress the final third of the night or remove it altogether. This is one reason many people feel mentally crowded and emotionally reactive throughout the day.

They are missing a window their body was designed to experience.

A Balanced Perspective

Tahajjud is not an obligation for every Muslim, and waking early is not possible for everyone at every stage of life. The Sunnah emphasises balance, not strain.

Even occasionally experiencing this window can be meaningful. Once or twice a week. A short period. No pressure.

Consistency over intensity applies here too.

A Shared Human Design

What makes this practice so compelling is that it reveals something universal. A rhythm built into the human body long before modern science measured it.

Islam named it, protected it and gave it purpose. Science is now explaining it.

Whether through prayer, reflection or quiet awareness, the last third of the night remains one of the most physiologically supportive times for clarity, grounding and presence.