Feeling constantly tired can be frustrating and worrying. Many people with prediabetes describe exhaustion, brain fog, or the sense that they “just don’t have any energy anymore.” Sometimes this relates to blood glucose levels, but often there are several overlapping causes.

This article explores the main reasons fatigue is common in prediabetes and what you can do about it. It also outlines when to see your doctor to rule out other important causes.

What Does Fatigue in Prediabetes Feel Like?

People often describe:

Struggling to get out of bed in the morning
Feeling “wiped out” after simple tasks
Difficulty concentrating or “fuzzy” thinking
Lack of motivation or interest in usual activities

Because fatigue builds up gradually, you may not realise how tired you were until things start to improve.

High and Low Blood Glucose

High blood glucose (hyperglycaemia) means that glucose is “stuck” in the bloodstream and not getting into cells efficiently. Your muscles and brain can feel as if they’re short of fuel, even when sugars are high.

Some people with prediabetes also experience reactive hypoglycaemia — a drop in blood glucose a few hours after a high-carbohydrate meal — which can cause shakiness, hunger, and profound tiredness afterwards.

If you suspect glucose swings may be contributing to your fatigue, talk with your doctor about whether short-term home monitoring or a continuous glucose monitor (CGM) would be helpful. For more on monitoring, see: How is prediabetes monitored?

Sleep Problems and Sleep Apnoea

Good sleep is essential for energy, mood, and healthy metabolism. Ongoing sleep disruption can worsen insulin resistance and significantly increase fatigue.

Common sleep-related issues in prediabetes include:

Obstructive sleep apnoea (OSA)
Frequent night-time urination
Insomnia, often related to stress or anxiety

Obstructive sleep apnoea occurs when the airway repeatedly collapses during sleep, causing loud snoring, pauses in breathing, and drops in oxygen levels. It is more common in people who are overweight, especially men with larger neck sizes.

If your partner notices loud snoring, gasping episodes at night, or you wake unrefreshed every morning, talk to your doctor about a sleep assessment. Treating sleep apnoea often improves both energy and blood glucose control.

For more on sleep and insulin resistance: Too much or too little sleep and insulin resistance

Weight, Hormones, and Other Medical Conditions

Several other factors can contribute to fatigue in people with prediabetes:

Weight gain – carrying extra weight makes everyday tasks more tiring and worsens insulin resistance.
Low testosterone in men – more common with central obesity and associated with tiredness, low mood, and reduced muscle strength.
Thyroid disorders – low thyroid function (hypothyroidism) is a common cause of fatigue.
Nutrient deficiencies – such as low iron, vitamin B12, or folate.
Kidney or liver problems – sometimes related to long-term metabolic changes.

Many of these can be checked with simple blood tests organised by your doctor.

Stress, Mood, and Fatigue

Living with health worries, work stress, or family pressures is exhausting. Chronic stress and anxiety:

Increase levels of stress hormones, which raise blood glucose
Make it harder to sleep
Reduce motivation to eat well or exercise

Over time, this can create a vicious cycle of worsening fatigue, stress, and glucose control. It is very common to experience low mood or worry after being told you have prediabetes. You can read more here: Prediabetes and mental health

What to Do If You’re Always Tired

If fatigue is affecting your quality of life, it’s important not to ignore it. Practical steps include:

Book a review with your doctor – discuss your symptoms, ask for appropriate blood tests, and review medications.
Check your sleep – consider a sleep study if sleep apnoea is suspected.
Stabilise meals – regular, balanced meals can reduce glucose swings.
Move gently – even light activity can boost energy over time.
Seek emotional support – from a psychologist, counsellor, or support group if needed.

Helpful related articles:

Get Help Understanding the Bigger Picture

If you’d like to see how fatigue, prediabetes, and insulin resistance fit together — and what to do in practical steps — you can join the free webinar:

Join the Prediabetes & Insulin Resistance Masterclass →

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Why Do I Feel So Tired with Prediabetes?