Welcome to the final day of January — honestly, where has the time gone?
One topic that’s come up this month with my clients this month is thyroid health, and it’s such an important (and often misunderstood) area. That’s what inspired me to write today’s article, exploring what the thyroid doesand what can happen when thyroid function is out of balance.
If you’ve been feeling “off” and can’t quite put your finger on why, this is well worth a read.
This comes up a lot — and it’s confusing because thyroid symptoms often overlap with stress, perimenopause, burnout, under-fueling, and poor sleep.
Here’s a clear, no-nonsense way to understand it
First: what does the thyroid actually do?
Your thyroid is your metabolic regulator. It influences:
- Energy levels
- Body temperature
- Heart rate
- Digestion
- Mood and focus
- Weight regulation
- Hair, skin, and nails
When it’s out of balance, everything can feel off.
Overactive thyroid (Hyperthyroid)
This means your thyroid is producing too much thyroid hormone — your system is essentially stuck in fast-forward.
Common symptoms:
- Feeling wired, anxious, or on edge
- Racing heart or palpitations
- Heat intolerance, excessive sweating
- Unexplained weight loss
- Shaky hands
- Poor sleep or insomnia
- Frequent bowel movements or diarrhoea
- Irregular or lighter periods
- Muscle weakness despite training
How it often feels:
“I can’t switch off, I feel revved up but exhausted.”
Underactive thyroid (Hypothyroid)
This means your thyroid is producing too little thyroid hormone — everything slows down.
Common symptoms:
- Persistent fatigue (even after rest)
- Feeling cold when others aren’t
- Weight gain or difficulty losing weight
- Brain fog, low mood, or depression
- Dry skin, hair thinning, brittle nails
- Constipation
- Heavy or irregular periods
- Low motivation
- Puffiness in the face or eyes
How it often feels:
“I’m tired, flat, foggy, and my body won’t respond.”
Why it’s easy to misread
Many symptoms overlap with:
- Chronic stress
- Perimenopause / menopause
- Overtraining
- Undereating
- Poor recovery
- Nervous system dysregulation
This is why so many women are told “your bloods are normal” — yet still feel awful.
How do you actually know which it is?
You can’t diagnose this on symptoms alone.
You need proper blood tests, ideally including:
- TSH
- Free T4
- Free T3
- Thyroid antibodies (to check for autoimmune causes)
A single TSH test doesn’t always tell the full story.
A really important note
Chronic stress can suppress thyroid function over time.
So someone may not have a thyroid disease, but their thyroid output is being affected by prolonged nervous system overload.
That’s why:
- Logic disappears
- Habits fall apart
- Fat loss stalls
- Energy crashes
The body is prioritising survival, not optimisation.
If this feels like you
The smartest next steps are:
- Don’t self-diagnose
- Track symptoms honestly
- Look at stress, sleep, fuel, and training load
• • Get proper testing if symptoms persist
What do you think?
Let me know via whats app 07976 268672 or my facebook group
Rachel x
Ps For my local Reformer & Hot classes in my studio in Derbyshire click here
PPS I set a goal this year to start a weekly vlog and document running a fitness business, being a training provider, organising events and post in on Youtube every Saturday if you would like to watch here is this weeks id love your thoughts
You can email me, WhatsApp me on 07976 268672, or share your thoughts in my Facebook group.
Quick Update on My Daily Online Classes.
I’ve launched a brand-new PAYG option for my daily online classes
I trial all of my new workout formats, class ideas and concepts inside my online platform, Studio Live Club — so it’s the perfect place to dip in whenever you fancy a workout, want to try something new, or need fresh inspiration for your own teaching.
With PAYG, there’s no subscription or membership.
Simply create an account, log in, and join the Workout of the Day.
Train with me live or
Catch up on demand
Enjoy 24 hours’ access to that day’s classes
Access all of the days classes – Walkfit, Stretch Express, Fitness Pilates sculpt
