Why Sleep is the Unsung Hero of Hormonal Balance
Whenever I’m asked..
“What’s the one thing I can do to improve my health, above everything else?”
My answer is always the same: SLEEP!
Now...before you think this is just going to tell you to “sleep more”… I urge you to keep reading...
You need to understand WHY sleep has to be a non-negotiable priority!
Everything else about your life could be perfectly geared towards performance and longevity...your training, your diet, your supplements, your stress management, but if you’re not getting enough sleep, you are simply wasting your time!
Sleep is not passive rest.
It’s an active recalibration system that resets your hormones, metabolism, and brain... EVERY... Single... Night!
Let’s see if I can surprise you about sleep...
Cortisol and Melatonin:
Your hormones follow a rhythm, just like the sun.
Cortisol should rise in the morning, giving you the energy to get up and go.
Melatonin should rise in the evening, helping you wind down and switch off.
When sleep is cut short or erratic, this rhythm goes out of sync. Cortisol stays high at night, melatonin gets blunted, and suddenly you’re wired when you want to be tired… and tired when you need to be awake.
'Ben, I already knew that, you need to try harder'...
'Ok, ok, how about this'...
What about Ghrelin and Leptin?
Firstly, what are they?
Ghrelin: Think of ghrelin as your hunger signal. It rises when you’re short on sleep, making you feel hungrier and crave more food than usual.
Leptin: Leptin is your fullness signal. It tells your brain you’ve eaten enough, but with poor sleep that signal gets weaker, so you don’t feel as satisfied.
So sleep — or a lack thereof — literally changes how hungry you feel.
The result? Cravings, overeating, and creeping weight gain that people often blame on “willpower.”
Want to geek out?
Effects of acute sleep loss on leptin, ghrelin, and adiponectin in adults with healthy weight and obesity: A laboratory study — PubMed
Pretty wild, ay?
Sleep, Reproduction and Beyond
For women, poor sleep can disrupt the delicate balance of oestrogen and progesterone, leading to irregular cycles, PMS, or fertility challenges.
For men, even a few nights of reduced sleep has been shown to lower testosterone levels significantly.
"Ok Ben, fine, I'll go to bed earlier"...
"Wait, there's more"...
Sleep and Your Metabolism
Insulin sensitivity (how well you manage blood sugar) drops after just one night of bad sleep.
Over time, that’s one reason chronic sleep loss is linked to type 2 diabetes and stubborn belly fat.
In fact, a 2022 study showed this happens faster than most people realise. Just a few nights of restricted sleep were enough to make cells less responsive to insulin, meaning your body had to pump out more to deal with the same amount of sugar.
That’s the first step towards insulin resistance and all the knock-on effects that follow.
My Final Thoughts
Sleep isn’t just about feeling rested. It’s the foundation that keeps every hormone in harmony — from stress and appetite to reproduction and metabolism.
If you want a simple, powerful lever for your health: prioritise sleep like your life depends on it… because in many ways, it does.
Aim for roughly 10pm–6am where possible — those hours most closely mirror our natural circadian rhythm.
It’s when your body does its deepest repair work, balances hormones, and resets the systems that keep you performing at your best.
About the Author
Ben Cooper is a Registered Nutritional Therapist, Functional Medicine Practitioner, and founder of Cooper Coaching and ReCooper8 — online programmes dedicated to gut health, hormonal balance, and cardiovascular wellness.
With over 15 years in the health industry, Ben helps clients uncover the root causes of fatigue, hormonal imbalance, and poor recovery — empowering them to rebuild health from the inside out.