Can Staying Under the Covers Too Long Affect Your Hormones? What Sleep Experts Want You to Know

Sleep is important for many reasons. It affects your hormones, and your hormone levels, in turn, affect your sleep. But what does this have to do with the amount of time we spend under the covers? A new study suggests that spending too much time tucked beneath warm blankets can indeed influence our hormonal balance.

What Are Hormones and What Do They Do?

Hormones are chemical messengers that play a vital role in regulating the body's many processes, systems, and functions. The body depends on a wide variety of hormones to function properly. These hormones are released through the endocrine system and are responsible for numerous functions, including:

• Growth and development

• Metabolism

• Appetite

• Body temperature regulation

• Blood pressure

• Sleep-wake cycles

• Reproductive health

• And much more

Adequate sleep is essential for regulating several key hormones, including:

• Cortisol

• Estrogen and progesterone

• Hunger-related hormones such as insulin, leptin, and ghrelin

• Melatonin

• Thyroid hormones

• Growth hormones

According to Dr. Sara Gottfried, a professor in the Department of Integrative Medicine and Nutritional Sciences at Thomas Jefferson University, “Almost every hormone in the body is released in response to a rhythm known as the sleep-wake cycle. When this rhythm is ignored, poor sleep can cause you to slide down the hormonal staircase, regardless of your age.”

Dr. Abhinav Singh, Medical Director of the Indiana Sleep Center, agrees: “Consistent sleep helps regulate hormones. Whenever we chronically disrupt the quantity or quality of sleep, we disturb that balance and leave the door open to medical problems.”

The Role of Sleep in Hormonal Balance

Sleep plays a major role in regulating cortisol, a steroid hormone produced by the adrenal glands. Often called the “stress hormone,” cortisol also helps regulate many other hormones in the body.

“When you relax, sleep well, and wake feeling restored, your cortisol reaches its peak within 30 minutes of waking,” explains Dr. Gottfried. “That peak activates many of your other hormones, including thyroid hormones and estrogen.”

Estrogen and progesterone are essential for maintaining reproductive health. According to Dr. Gottfried, “When you don’t sleep well, cortisol remains elevated when you wake up in the morning. This can disrupt the balance between estrogen and progesterone. It can also slow down thyroid function, which may affect your metabolism.”

How Does Staying Under the Covers Affect Hormones?

Dr. Gottfried explains:

“The body’s biological clock is primarily regulated by daylight. When someone stays under the covers for an extended period — especially in a dark room in the morning, the body may continue to ‘think’ it is still nighttime. As a result, it continues producing melatonin, the sleep hormone, instead of shutting it down.

“When melatonin remains elevated beyond nighttime hours, it can delay the rise of cortisol, the hormone responsible for alertness and energy.

“Cortisol is supposed to increase in the morning and help regulate wakefulness, blood pressure, blood sugar, and energy levels. When that rise is delayed, people may experience heaviness, fatigue, and even mental fog.

“In addition, when you remain under a warm blanket, your body temperature stays stable. Normally, there is a slight increase in core body temperature in the morning, signaling that the day has begun. When that temperature shift doesn’t occur, the body may struggle to transition hormonally from sleep mode to wakefulness.”

Is It Really a Problem?

Dr. Gottfried emphasizes that this is not about spending one lazy morning under the covers.

“It’s not a single day that causes problems,” she says. “Hormonal disruption develops when this becomes a daily habit throughout the winter.”

In other words, occasionally enjoying a slow morning is unlikely to harm your health. However, regularly staying in bed long after waking — especially in a dark environment, may interfere with your body’s natural hormonal rhythms and make it harder to feel alert, energized, and balanced throughout the day.