Why You Feel Tired All the Time in Perimenopause (And What’s Really Behind It)

If you’re feeling constantly tired — even after a full night’s sleep — you’re not alone.

Many women in their 40s say:

“I wake up tired, hit a wall in the afternoon, and by evening I have nothing left.”

It can feel frustrating, especially if you’ve always been someone with good energy.

But this kind of fatigue isn’t random — and it’s not just “getting older.”

There are real physiological changes happening during perimenopause that can leave you feeling depleted.

What’s actually causing the fatigue?

Perimenopause is a time of hormonal transition — and those hormonal shifts affect far more than just your cycle.

Energy, mood, sleep, and metabolism are all closely connected.

Let’s look at what’s often going on beneath the surface.

1. Fluctuating hormones affect your energy systems

During perimenopause, oestrogen levels don’t just decline — they fluctuate.

These fluctuations can:

• impact your energy levels

• affect brain function and focus

• disrupt how your body regulates temperature and sleep

Progesterone, which has a calming effect, also begins to decline — which can leave you feeling more wired, anxious, or restless.

2. Sleep is often disrupted (even if you don’t realise it)

You may still be getting “enough” hours of sleep — but the quality may have changed.

Common patterns include:

• waking during the night

• lighter, less restorative sleep

• waking early and not being able to get back to sleep

Even subtle changes in sleep quality can lead to significant fatigue over time.

3. Blood sugar imbalances drain your energy

If your blood sugar is fluctuating throughout the day, your energy will too.

This can look like:

• feeling okay in the morning, then crashing mid-afternoon

• needing caffeine or sugar to get through the day

• feeling shaky, irritable, or foggy when you haven’t eaten

Blood sugar instability is very common during perimenopause and is often overlooked.

4. Stress and cortisol take a toll

Midlife is often a busy, demanding time — and your body becomes more sensitive to stress.

When cortisol (your stress hormone) is elevated over time, it can:

• disrupt sleep

• drain energy

• leave you feeling “wired but tired”

You may feel like you’re constantly pushing through, without ever fully recharging.

5. Nutrient demands increase

Your body’s needs change during this time.

Factors like:

• long-term stress

• past dieting

• digestive changes

can all affect how well you absorb and utilise nutrients.

Low levels of key nutrients can contribute to:

• fatigue

• low mood

• poor stress resilience

6. Thyroid function can be affected

The thyroid plays a central role in energy production.

During perimenopause, thyroid function can shift, or symptoms may become more noticeable.

This can contribute to:

• persistent fatigue

• feeling cold

• brain fog

• changes in weight

It’s an important piece to consider when fatigue feels ongoing and unexplained.

Why this fatigue feels different

This isn’t just being “a bit tired.”

Many women describe it as:

• a deeper exhaustion

• a lack of motivation or drive

• feeling like they’re not quite themselves

And often, they’re told everything is “normal.”

But just because it’s common doesn’t mean it should be ignored.

What actually helps

Supporting fatigue in perimenopause isn’t about pushing through — it’s about working with your body.

1. Stabilise your energy through food

Balanced meals can make a significant difference.

Focus on:

• protein with each meal

• healthy fats

• whole, fibre-rich foods

This helps keep blood sugar steady and supports sustained energy.

2. Support sleep quality

Even small changes can improve how rested you feel.

This might include:

• a consistent sleep routine

• reducing stimulation in the evening

• creating a calm wind-down period

3. Reduce the “background stress” load

You don’t need to eliminate stress — but supporting your nervous system is key.

Simple, realistic approaches often work best:

• slowing down where possible

• spending time outdoors

• building in moments of rest

4. Look at the bigger picture

Fatigue is rarely caused by one thing alone.

It’s usually a combination of:

• hormones

• blood sugar

• stress

• sleep

• nutrients

This is why a more personalised, holistic approach can be so helpful.

5. Consider targeted support

In clinic, support is tailored to the individual but may include:

• nutritional support

• herbal medicine

• support for sleep and stress

• investigating underlying drivers

A more understanding approach

If you’re feeling constantly tired, it’s not a reflection of your motivation or resilience.

It’s your body asking for support.

When you begin to understand what’s driving that fatigue, things can start to shift in a much more manageable way.

If this sounds familiar

This is something I support women with often — helping them understand why they feel the way they do and creating a plan that feels achievable and supportive.

Final thoughts

You’re not meant to feel exhausted all the time.

Perimenopause is a transition — but with the right support, it can be one where you feel steady, clear, and energised again.