The first days back at work after the holidays are a transition. The alarm rings earlier. The kids are back in school and the house is quiet again.
At the clinic, patients ask how the break was, and I answer honestly that it was enjoyable and restful. And yet, by midmorning, there is a feeling of heaviness and fatigue. Nothing dramatic, but persistent.
This kind of tiredness is common after time off or vacation. Because sleep schedules become erratic, meals become heavier and less predictable, physical activity drops and circadian rhythms are disrupted. Even brief changes in routine can linger. For most, this resolves within days to a couple of weeks as regular patterns return.
But it is important to note that being tired isn’t always “just being tired.”
Fatigue is one of the most common and non-specific symptoms in medicine. While often benign, it can also be an early sign of underlying disease. The challenge lies in knowing when to wait, and when to investigate.
One frequently overlooked cause is an underactive thyroid or the condition called hypothyroidism. Patients may report persistent fatigue accompanied by weight gain, feeling cold, constipation, dry skin or slow thinking. Because the onset is gradual, symptoms are often attributed to stress or aging. This can be checked with a routine blood test like thyroid stimulating hormone (TSH).
Endocrine causes extend further. A lack of cortisol in the condition known as adrenal insufficiency, though uncommon, can present with profound fatigue, dizziness, low blood pressure, weight loss and salt craving. Because symptoms are vague, diagnosis is also frequently delayed.
Sleep disorders, particularly obstructive sleep apnea, are another major contributor. Patients may sleep for many hours yet wake unrefreshed, struggle with daytime sleepiness, or experience morning headaches and poor concentration. Snoring is often dismissed, but untreated sleep apnea carries significant cardiovascular and metabolic risk.
Fatigue may also be a manifestation of heart disease, especially in women and older adults, where unexplained exhaustion or reduced exercise tolerance may precede classic chest pain.
Chronic fatigue may also be a symptom of anemia, uncontrolled diabetes, chronic kidney disease, inflammatory disorders, depression, menopause or medication effects. Often, more than one factor is present.
The post-holiday period can unmask these conditions. When life slows down, symptoms that were previously compensated for become harder to ignore. What feels like seasonal sluggishness may, in some cases, be a signal for something more serious.
At the same time, not every tired patient needs extensive testing. Fatigue must be interpreted in context — its duration, severity and other associated features matter.
Consider seeking a doctor’s opinion if your fatigue:
•Persists beyond two to three weeks in spite adequate rest
•Worsens rather than improves with return to routine
•Interferes with daily function or work performance
•Is accompanied by weight change, chest pain, shortness of breath or lightheadedness
•Feels disproportionate to your activity level
•Occurs with sleep that feels inadequate, loud snoring or daytime sleepiness
Fatigue is common, but it is never meaningless. Sometimes the body is recalibrating, sometimes it is signaling us to pay more attention to our health. Take some time to rest, but if it doesn’t seem to be helping, take the time to go see your doctor.