Understanding Sleep: How It Impacts Mood, Energy, Hormones, and More
If you’ve ever had a restless night and felt off the next day, you already know sleep is important. But sleep isn’t just about avoiding yawns—it’s a powerful biological process that impacts nearly every system in your body.
When we prioritize sleep, we improve our mood, energy, and even our hormone balance. When we don’t… well, our bodies let us know. Let’s break down why sleep matters, what can get in the way, and how you can give yourself the best chance at deep, restorative rest.
Why Is Sleep So Important?
Think of sleep as your body’s nightly repair session. During the deepest stages of sleep, your brain clears waste, your muscles and tissues heal, and your hormones reset for the next day.
Sleep plays a role in:
Memory and learning
Immune system strength
Emotional regulation
Energy restoration
Hormone production and balance
When we skimp on sleep, whether from busy schedules, stress, or habits that disrupt rest, these systems don’t get the maintenance they need.
As Dr. Matt Walker explains in his book Why We Sleep, harnessing the power of quality rest can improve learning, mood, and energy levels; regulate hormones; help prevent serious diseases; slow the effects of aging; and even increase longevity. His research makes it clear—sleep is one of the most powerful health tools we have, and it’s completely free.
Things That Affect Your Sleep (and How)
Several daily choices and environmental factors can help or hinder your ability to sleep well:
Timing – Going to bed and getting up at the same time are critical components of quality sleep, as they set the body's clock for hormonal and other rhythms essential to health. Anchor your sleep cycle by rising and going to bed in sync with natural daylight—essential for your body’s ‘clock’ and every bodily function.
Temperature – A cooler room (around 65–68°F) helps your body naturally lower its core temperature, a signal that it’s time to sleep.
Light & Dark – Exposure to bright light (especially blue light from screens) in the evening can suppress melatonin, the hormone that helps you fall asleep. Darkness tells your brain it’s time to rest.
Caffeine – This stimulant can stay in your system for 6–8 hours. Even if you can fall asleep after an afternoon coffee, your deep sleep may be lighter or shorter.
Alcohol – While it may help you fall asleep faster, alcohol disrupts your sleep cycles, especially REM sleep, leaving you less rested.
Cannabis – Some people find it relaxing, but cannabis can also reduce time spent in REM sleep, affecting memory and emotional processing.
Nutrition – Heavy, high-fat, or spicy meals before bed can disrupt sleep by increasing digestive demands.
Meal Timing – Eating too close to bedtime can cause discomfort or reflux, while going to bed hungry may also make it harder to drift off.
How Sleep Affects Mood & Energy
There’s a reason so many experts and doctors are discussing sleep. It impacts more than we think. We all know that not getting enough sleep can impact your energy and mood the next day or even days. But it isn’t just about how many hours you sleep—it’s about the quality of that sleep.
Poor sleep can:
Increase irritability
Heighten anxiety
Lower resilience to stress
On the flip side, good sleep improves emotional stability and supports better decision-making. Deep, restorative sleep allows your muscles, brain, and nervous system to recover from the day. When sleep quality is poor, you may feel sluggish even after a full night in bed. It’s much easier to feel patient, optimistic, and motivated after a full night’s rest.
If you are looking to dive deeper, Dr. Andrew Huberman and Dr. Matt Walker discuss the ways improving sleep can boost mood and energy in this episode on the Huberman Lab podcast.
What This Means for Men in Midlife
For men in their 40s, 50s, and beyond, sleep quality becomes even more important—and sometimes, more challenging to maintain. Changes in hormones, lifestyle stressors, and health conditions can all affect how well (and how deeply) you sleep.
Poor sleep in midlife can:
Lower testosterone levels, which impact energy, mood, muscle mass, and libido
Increase cortisol, making it harder to manage weight and stress
Raise the risk for heart disease, diabetes, and cognitive decline
Decrease resilience, making you feel more fatigued and less motivated
On the flip side, improving sleep can:
Boost morning energy and mental clarity
Support healthy hormone production
Improve mood and stress tolerance
Enhance recovery from exercise and physical activity
For men in midlife—especially those with high-pressure careers—restoring healthy sleep patterns can be a game changer for performance, health, and overall quality of life.
Dr. Dawson’s Take
If you’ve been feeling tired, moody, or “off,” it’s worth looking at your sleep. It’s one of the most powerful and most overlooked tools for improving your health.
Small changes, like setting a consistent bedtime, keeping your bedroom cool and dark, and limiting caffeine or alcohol in the evening, can make a noticeable difference in just a few weeks. Download our guide to unlock the secrets of a good night's sleep.
As a board-certified sleep physician, I’ve helped countless patients improve their rest—and their overall quality of life. Book a consultation to learn how we can get you sleeping and feeling better.