Hello and welcome back to Making Sense of Women's Health. I am Roberta Bass and I am a women's health physiotherapist, a remedial hypnotist, Pilates instructor and menopause mentor. This week is Sleep Awareness Week, so it is the perfect time to explore sleep from a new perspective — how it actually works, why it's so vital for our health, and how we can use this knowledge to sleep better.

We know that sleep is important, but do we really understand why? What exactly happens in the brain and body when we sleep? And why does menopause, ageing and even our diet make such a difference? In today's episode, I'll talk you through the science of sleep, how hormonal shifts and lifestyle factors can disrupt it, and how to optimise your body's natural sleep rhythms for deeper, more restorative rest.

So firstly, what happens when we sleep?

Sleep isn't just about resting — it's a highly active biological process where the body and brain go through different stages of restoration. Each sleep stage has a unique role in physical and mental health. So there's four different stages of sleep.

Stage one is our light sleep. So this is the transition from wakefulness to sleep. This lasts one to seven minutes and the brain produces theta waves and muscle activity slows down. People experience sudden muscle jerks or the sensation of falling at this stage.

Then we move on to stage two, which is still light sleep, but this lasts for about 10 to 25 minutes and just involves further relaxation. The brain activity shows sleep spindles and K-complexes which help process information and stabilise sleep. It is the longest stage of sleep and it makes up about 50% of the total of our sleep time.

Then we will go into our deep sleep or our slow wave sleep. This generally lasts 20 to 40 minutes and is the most physically restorative stage. The body repairs muscles and tissues, it supports our immune function and helps to regulate our hormones. Our brain activity is dominated by delta waves. This stage is also essential for memory consolidation and emotional regulation.

Then we have our REM sleep, which is often known as our dream sleep. It occurs about 90 minutes after we fall asleep and this can last for 10 to 60 minutes. This bit is essential for our memory consolidation, our emotional regulation and our cognitive function. Our brain activity is similar to wakefulness and this is where our dreaming occurs. The longer you sleep, the longer your REM period becomes and final REM cycle often lasting up to an hour.

We cycle through these stages. Now a full sleep cycle lasts about 90 to 120 minutes. Generally, that first cycle is a little bit shorter and then later cycles become a little bit longer. And each night, depending on how long we are asleep for, we tend to cycle through four to six of these cycles. As the night progresses, our deep sleep reduces while our REM sleep increases. Waking up mid-cycle can leave you feeling really groggy while waking at the end of the cycle can mean that you're more refreshed. If the sleep cycles are disrupted by waking up frequently or not getting enough REM or deep sleep, you may feel exhausted even if you feel like you've had a full night's rest.

So how much sleep do we actually need?

Sleep needs change as we age and this is due to brain development, hormonal shifts and lifestyle factors. So we think of newborn babies — up to three months they need 14 to 17 hours of sleep. If they get a little bit older, four to 12 months, then we're needing 12 to 16 hours. Unfortunately, this isn't all in one go because it does include naps — and if they're anything like my babies were, they don't sleep through the night at all, but they do need a lot of sleep.

Toddlers need slightly less — so we're looking at 11 to 14 hours. This is because the amount of development that happens in those first few years. Preschoolers, three to five years, they tend to need 10 to 13 hours, again probably will include some naps. School-aged children tend to need nine to twelve hours.

Teenagers need slightly less — eight to ten hours. Adults then need seven to nine hours until we get to about 65 and then we might need slightly less — around seven to eight hours.

The reason that our needs change so much is due to brain development. Babies and children need more sleep because it supports that rapid brain growth, their learning and memory consolidation. Hormonal changes — now teenagers, if they're anything like mine, you'll notice that they change with their hormones, but they also experience shifts in their circadian rhythm, so it often makes them night owls. My daughter particularly, she wakes up at night time, she's really happy — morning, grumpy as anything, doesn’t want to get up.

Lifestyle and stress can have an effect as well. Adults have work, family, stress-related disruptions, and that will impact sleep. Ageing does have an effect — older adults may experience lighter sleep, they might wake up more frequently, they may wake early and this can be down to hormonal changes and also other health conditions that may cause problems.

So what does disrupt our sleep?

Stress and anxiety — chronic stress and anxiety both elevate our cortisol levels. They keep the body in a state of alertness and this makes it difficult to relax and unwind. If you're having racing thoughts and worries, this can delay sleep onset and can cause you to wake up frequently throughout the night. Stress management, deep breathing, meditation, and journaling can really help to reduce stress hormones.

Hormonal changes — menopause, pregnancy, even the menstrual cycle can impact our sleep patterns. Menopausal women often will experience night sweats and hot flushes which disrupt sleep. Pregnant women may struggle with discomfort and needing to get up regularly to go for a wee. During the menstrual cycle, when progesterone levels drop, this can cause restless sleep.

Bladder problems — if you’re getting up regularly to go for a wee, this can really disrupt sleep. Make sure you’re not drinking too much before bed — allow 90 minutes from your last drink to clear your system. Avoid caffeine and alcohol, which irritate the bladder and disrupt sleep.

Caffeine can still affect sleep even six hours after drinking it. Keep it to mornings only if you can. Alcohol might make you feel sleepy but disrupts REM sleep, leaving you unrefreshed.

Blue light from screens blocks melatonin, delaying sleep onset. Reduce screen time 1-2 hours before bed or use blue light filters.

Inconsistent schedules confuse the body’s internal clock. Shift work, late nights, and weekend lie-ins all make it harder to maintain good sleep.

Environment matters — light, noise, temperature, even your partner’s snoring can disturb you. Eye masks, earplugs or white noise can help.

Pain from arthritis, fibromyalgia, migraines, or acid reflux makes it hard to get comfortable. Good sleep positioning, pillows, or even seeing a physio can help.

Diet — sugary snacks before bed spike blood sugar and cause wakefulness. Aim for protein-based snacks like Greek yoghurt or almonds.

To improve sleep, focus on regular schedules, calming evening routines, managing stress, exercising regularly, limiting caffeine and alcohol, addressing bladder issues, optimising your sleep environment, and eating for stable blood sugar.

If this episode has been helpful, please share it and subscribe so you don’t miss the next one. Sweet dreams and see you next time.