Ever have days where no amount of coffee seems to help, and by mid-afternoon you’re wondering how anyone can survive this tiredness? Feeling sluggish isn’t always just about a busy schedule or lack of sleep. Sometimes it’s your thyroid quietly throwing your energy levels off balance.
What Your Thyroid Actually Does
The thyroid is a small, butterfly-shaped gland at the base of your neck. Despite its size, it has a big job: producing hormones that regulate your metabolism, energy use, heart rate, and even body temperature. When it’s working well, you hardly notice it. But if your thyroid slows down — a condition called hypothyroidism — your body’s systems can feel a bit sluggish.
How Hypothyroidism Can Show Up
The sneaky thing about an underactive thyroid is how gradually symptoms appear. You might notice weight creeping on despite no changes to your diet, feeling colder than others, or hair and nails becoming brittle. Constipation, low mood, and “brain fog” often arrive alongside fatigue (Healthline). Because these changes are subtle at first, many people dismiss them — until they realise their energy isn’t what it used to be.
Why Your Thyroid Might Be Slowing Down
Several factors can cause hypothyroidism. In New Zealand, the most common is Hashimoto’s thyroiditis, an autoimmune condition where the body attacks the thyroid. Other causes include previous thyroid surgery or radiation, certain medications, or iodine imbalances. Occasionally, the pituitary gland — which signals your thyroid to produce hormones — can also be involved.
How It’s Diagnosed
The key to finding out if your thyroid is behind your fatigue is a blood test. Doctors usually measure TSH (thyroid-stimulating hormone), which rises if your thyroid is underactive, and T4 (thyroxine), the hormone your thyroid produces. Sometimes, they check thyroid antibodies to see if Hashimoto’s is involved. These tests are quick and straightforward, but they can make a huge difference in understanding why you feel so drained.
Treatment: Simple But Life-Changing
If you’re diagnosed with hypothyroidism, the usual treatment is thyroxine, a daily tablet that replaces the hormone your body isn’t making enough of. Doctors start with a low dose and adjust it over time, checking your blood to make sure it’s the right amount (Info Health NZ). Many people notice a real boost in energy, mood, and focus once their hormone levels are balanced.
What About an Overactive Thyroid?
It’s worth noting thyroid problems don’t always mean low energy. Hyperthyroidism, or an overactive thyroid, is less common but can also affect your wellbeing. In this case, your thyroid produces too much hormone, which speeds up your metabolism instead of slowing it down. People with hyperthyroidism often feel anxious, jittery, or unusually warm, may lose weight unexpectedly, and sometimes experience rapid heartbeat or trouble sleeping. While fatigue can still occur, it usually comes alongside these other noticeable symptoms.
When to See a Doctor
If fatigue is persistent, doesn’t improve with rest, or comes with other symptoms like unexpected weight gain, feeling unusually cold, or brain fog, it’s worth talking to your GP about a thyroid check. Even if you’re already on thyroid medication, ongoing tiredness may signal a dose adjustment or additional factors such as low iron or vitamin deficiencies.
Feeling constantly tired isn’t something you have to just accept. While an underactive thyroid can be subtle, it’s very treatable. Being aware of both underactive and overactive thyroid signs can help you understand what’s going on in your body. If you suspect your thyroid might be slowing you down — or speeding things up — a conversation with your GP and a simple blood test could be the first step toward reclaiming your energy and feeling like yourself again.
