Written by Dr Zamiel Hussain, Lead GP and Founder of AccessGP
Feeling tired is one of the most common reasons people seek GP advice. By February, many expect their energy to have returned after Christmas and the New Year reset. Instead, fatigue often lingers and starts to affect concentration, motivation and daily life.
Fatigue is not a diagnosis on its own. It is a symptom, and understanding the cause matters far more than trying to push through it.
Why fatigue is so common in late winter
From a clinical perspective, there are several reasons fatigue peaks at this time of year:
- Short daylight hours and low vitamin D levels
- Disrupted sleep patterns that never fully reset
- Recent viral infections such as flu, COVID or chest infections
- Ongoing work pressure or stress
- Reduced physical activity
- Poor quality rest rather than true recovery
For many people, fatigue is caused by a combination of physical, psychological and lifestyle factors rather than a single problem.
What fatigue can feel like
Patients often describe fatigue as more than just feeling sleepy. Common features include:
- Low energy even after rest
- Brain fog or difficulty concentrating
- Reduced motivation
- Feeling physically heavy or slowed
- Needing much more effort to complete everyday tasks
If this persists, it deserves attention.
Common causes of ongoing fatigue
From a GP perspective, persistent fatigue is usually multifactorial. Common contributors include:
Post-viral fatigue
After infections such as flu, COVID or chest infections, it is normal to feel drained for several weeks. Recovery is often gradual and can feel slower than expected, particularly if people return to full activity too quickly.
Poor sleep quality
Sleep duration alone is not enough. Fragmented or poor-quality sleep can leave people unrefreshed even after a full night in bed. Stress, alcohol, irregular routines, late screen use and disrupted circadian rhythms all play a role.
Stress, burnout and mental health
Mental exhaustion can feel just as physical as illness. Fatigue commonly overlaps with prolonged stress, burnout, anxiety or low mood. In these cases, tiredness often persists despite rest and improves only when the underlying issue is addressed.
Dietary factors and nutritional deficiencies
Diet plays a significant role in energy levels. Fatigue can be worsened by:
- Low iron levels, particularly in menstruating women
- Vitamin B12 deficiency
- Low vitamin D, which is common in winter
- Inadequate calorie or protein intake
- Highly processed diets with limited micronutrients
These issues are not always obvious without assessment and can contribute to both physical and cognitive fatigue.
Underlying medical conditions
Certain health conditions can present primarily with fatigue, including:
- Thyroid disorders
- Diabetes or pre-diabetes
- Anaemia
- Chronic inflammatory conditions
- Hormonal changes, including perimenopause and menopause
This is why ongoing or unexplained fatigue should not be dismissed.
Lifestyle and recovery imbalance
Low physical activity, long periods of inactivity after illness, dehydration and heavy reliance on caffeine can all worsen fatigue. Paradoxically, doing too little or trying to do too much too quickly can both delay recovery.
Medication effects
Some medications can contribute to fatigue as a side effect, including certain antidepressants, antihistamines, blood pressure medications and pain relief. A medication review can be helpful if symptoms started after a change in treatment.
When fatigue needs medical assessment
You should consider GP advice if fatigue:
- Lasts longer than four to six weeks
- Is worsening rather than improving
- Is affecting work or daily functioning
- Follows repeated infections
- Is associated with low mood or anxiety
What actually helps recovery
There is rarely a single fix. From a GP perspective, recovery usually involves:
- Re-establishing consistent sleep and wake times
- Gradually increasing activity rather than pushing hard
- Reducing alcohol and late caffeine
- Allowing proper recovery time after illness
- Being realistic about workload and expectations
“Persistent fatigue is often a sign that something needs addressing, not ignoring. Recovery is usually about small, consistent changes rather than dramatic interventions.”
Dr Zamiel Hussain, Lead at AccessGP
Where blood tests fit in
Blood tests are not always necessary, but they can be helpful when fatigue is persistent or unexplained.
A GP may consider tests such as:
- Full blood count
- Thyroid function
- Iron or vitamin B12 levels
- Vitamin D
- Diabetes screening where appropriate
The value lies in interpreting results in context, not in testing everything routinely.
You can explore explanations of common tests in our Knowledge Base.
How AccessGP can help
At AccessGP, fatigue is assessed holistically. This includes:
- A proper GP consultation
- Reviewing physical, psychological and lifestyle contributors
- Deciding whether investigations are appropriate
- Clear explanation and follow-up
Fatigue is common, but it should not be dismissed when it persists.
Key sources: AccessGP Clinical Knowledge Base; NHS UK, Tiredness and fatigue; NICE CKS, Fatigue; Patient.info, Fatigue.