Are You a Morning or Evening Person—And Does It Matter?

Robert Sapolsky, in his engaging talk “Morning vs. Night People” delves into the fascinating science of chronotypes—the biological preferences individuals have for when they feel most alert, active, or tired during a 24-hour cycle.

“Some people are strongly morning chronotypes, while others are clearly evening chronotypes. What does that look like in real life? It comes down to things like: What time do you prefer to go to sleep? What time do you like to wake up? What time of day do you feel most alert or active? When do you get the hungriest?”

These patterns aren’t just about habits—they’re deeply tied to circadian rhythms, which are influenced by hormones like melatonin and cortisol. Remarkably, chronotypes tend to remain stable over a lifetime, even as societal structures push us toward one-size-fits-all schedules.

A Forgotten Insight: What Midwives Observed

While most discussions on chronotypes focus on genetics, light exposure, and modern sleep science, there’s a lesser-known but intriguing perspective worth revisiting—the experiential knowledge of midwives, especially those who practiced in the 1940s and 1950s. In small, tight-knit communities, these women not only helped deliver babies but often followed their development over years. Some believed that the time of birth could influence a child’s natural rhythm and performance patterns later in life.

Though this idea hasn’t been scientifically validated, consistent observational knowledge across many births may offer a foundation for future inquiry. One midwife, who delivered me, once made an offhand comment when I was 14:

“You truly became a morning person—but you didn’t suckle right away.”

At the time, the statement seemed cryptic. But over the years, it began to make sense.

I was born at 6:30 a.m., and I’ve always felt my sharpest in the early morning. By noon, my energy drops dramatically (a pattern confirmed in lab tests), and I usually need to sleep by 9 p.m. This rhythm has been consistent throughout my adult life. Could this early alignment with daybreak—and how my body responded in the hours immediately after birth—have laid the foundation for my lifelong pattern?

Two Underexplored Factors: Birth Stress and Early Feeding

There are two biological variables that deserve closer scientific attention:

1. Cortisol Levels During Birth
   Birth is a physically intense and hormonally dramatic event. For both the mother and infant, cortisol—a stress hormone—spikes significantly. This surge may act as a sort of biological “reset,” helping to establish the newborn’s first circadian reference point.

2. The Role of Early Feeding—Especially Colostrum
   Immediately after birth, another crucial moment occurs: feeding. In particular, whether the infant receives colostrum, the first milk, or instead is given commercial formula.

   Colostrum is not only rich in protein, but also contains key immune and regulatory components like secretory immunoglobulin A (sIgA) and lactoferrin. These help establish gut health and immunity, but they may also influence metabolic and hormonal development in the first hours of life.

Midwives often noted whether a baby suckled right away or delayed feeding. This wasn’t just a practical observation—it may point to how an infant’s body initially regulated cortisol and glucose levels. For instance, a baby who feeds soon after birth typically sleeps shortly afterward. Is this because glucose reduces cortisol? Or because certain nutrients trigger a hormonal calming effect? Could delayed feeding or formula feeding alter this interaction?

These are questions science has yet to explore deeply.

Early Nutrition and Lifelong Rhythms

The implications may extend beyond infancy. Could early feeding—particularly the presence or absence of colostrum—affect not only immunity, but also energy regulation, alertness patterns, and even learning capacity later in life?

We already know that nutrition influences behavior. In classrooms, hungry children often struggle to concentrate. Some become restless or aggressive, while others shut down or withdraw. Perhaps these responses aren’t just short-term effects of low blood sugar, but signs of foundational rhythms set in infancy—shaped by cortisol regulation, metabolic flexibility, and early nutrient timing.

A Personal Observation

In my own life, I’ve noticed consistent and curious patterns:

• I wake naturally at sunrise and become drowsy soon after sunset.

• I rarely feel hungry within the first two hours of waking.

• I often feel sleepy after eating, especially meals rich in carbohydrates.

These rhythms seem more than behavioral—they feel biological. Could they have been influenced by the combination of my early morning birth, delayed first feeding, and the hormonal environment I was born into?

The Case for Further Research

While these ideas remain speculative, they open up an exciting and largely uncharted field of study:

How do birth timing, early feeding—especially the receipt of colostrum—and neonatal hormonal cascades interact to shape a person’s chronotype, stress tolerance, and cognitive potential?

A New View on Human Rhythms

Modern science rightly emphasizes genetics, environment, and lifestyle in determining chronotypes. But perhaps we also need to consider a fourth factor: early physiological imprinting. This includes not just what time you were born, but what happened in the hours afterward—who fed you, what you received, and how your body responded.

In conclusion, traditional knowledge from midwives, paired with modern endocrinology and chronobiology, may provide important clues about how we’re wired—and why we perform best at certain times of day without tipping into stress or fatigue.

Sometimes, understanding the rhythm of our lives means going all the way back to the first beat.

© 2000-2025 Sieglinde W. Alexander. All writings by Sieglinde W. Alexander have a fife year copy right. Library of Congress Card Number: LCN 00-192742