What could be causing my excessive fatigue as a 45-year-old male?

Evaluation of Excessive Fatigue in a 45-Year-Old Male

Your fatigue most likely stems from one of three common causes: thyroid dysfunction (particularly hypothyroidism), depression, or sleep disorders—and you need targeted laboratory testing plus assessment of psychological factors and sleep quality to identify the treatable cause.

Prioritize These Three Most Common Causes

1. Thyroid Dysfunction

• Hypothyroidism is one of the first and most important causes to investigate in your age group, as it frequently presents with fatigue and nonspecific symptoms 1
• Order thyroid-stimulating hormone (TSH) testing immediately as part of your core workup 2, 1
• This is a highly treatable cause that can dramatically improve your energy levels once identified 1

2. Depression and Psychological Factors

• Depression affects 18.5% of patients presenting with fatigue and is significantly more common in those complaining of tiredness 1, 3
• Studies show 25-33% of patients with fatigue also experience depression 2
• Overlooking psychological causes leads to inadequate treatment—this is a critical pitfall to avoid 2, 1
• Anxiety frequently accompanies fatigue and requires specific assessment 2, 1

3. Sleep Disorders

• Sleep disorders affect 30-75% of patients with fatigue, ranging from insomnia to sleep apnea 2, 1
• Missing sleep disorders results in incomplete management 1
• Assess for poor sleep hygiene: irregular sleep schedules, daytime napping, caffeine/alcohol consumption before bed, late-night screen use 4, 2
• Consider obstructive sleep apnea, especially if you have risk factors like weight changes or snoring 4

Essential Laboratory Workup

Order these core tests for moderate to severe fatigue 2:

• Complete blood count (anemia occurs in approximately 2.8% of patients with tiredness) 1, 3
• Thyroid-stimulating hormone 2, 1
• Basic metabolic panel (electrolyte imbalances in sodium, potassium, calcium, magnesium can cause fatigue) 4, 2
• Liver function tests 2
• Inflammatory markers like C-reactive protein 2

Additional testing based on clinical suspicion:

• Vitamin B12, folate, vitamin D, and ferritin levels (specific deficiencies are linked to fatigue) 1, 5
• Iron studies if anemia is present 2

Important caveat: Laboratory results affect management in only about 5% of fatigue cases, but testing remains essential to rule out treatable causes 2, 1, 6

Medication and Substance Review

• Review ALL current medications including over-the-counter drugs, herbals, vitamins, and supplements 4
• Certain cardiac medications (β-blockers) can cause bradycardia and subsequent fatigue 4
• Combinations of narcotics, antidepressants, antiemetics, and antihistamines contribute to excessive drowsiness 4
• Ignoring medication side effects can perpetuate fatigue—this is a common pitfall 2, 1
• Assess for alcohol or substance abuse patterns, as these can lead to or aggravate sleep disturbance and fatigue 4

Assess Physical Activity and Deconditioning

• Evaluate your current exercise patterns: Can you accomplish normal daily activities? What is your frequency and amount of exercise? 4
• Decreased physical activity worsens fatigue symptoms 2, 1
• Physical deconditioning is a significant contributor that requires assessment before formulating a treatment plan 4

Nutritional Assessment

Check for 4, 2:

• Weight changes and caloric intake alterations
• Impediments to nutritional intake (nausea, vomiting, loss of appetite)
• Electrolyte imbalances (often reversible with appropriate supplementation)
• Specific deficiencies: vitamin B6, B12, folate, ferritin, zinc, vitamin D, magnesium, copper, phosphate, calcium 1

Cardiac Evaluation (Age-Appropriate Consideration)

• At 45 years old, assess for cardiac dysfunction, particularly if you have cardiovascular risk factors 1
• Cardiac causes should be on your differential, though less likely without other cardiac symptoms 1

Initial Management Approach

Regardless of the specific cause identified, implement these evidence-based interventions:

Physical Activity (Strongest Evidence)

• Regular physical activity, including stretching and aerobic exercise such as walking, has the best evidence for managing fatigue 5, 6
• Start with low-level activities that gradually increase over time, especially if you're significantly deconditioned 4
• This applies even if you feel fatigued—exercise improves symptoms in most cases 4

Sleep Hygiene Optimization

• Maintain a regular sleep schedule 5
• Avoid daytime napping 5
• Eliminate caffeine and alcohol before bed 5
• Create a dark, quiet sleep environment 4, 5
• Reduce late-night screen time (gaming, TV, computer, cell phone, social media) 4

Treat Identified Causes

• If hypothyroidism is found, initiate thyroid hormone replacement 1, 5
• If depression is identified, consider selective serotonin reuptake inhibitors (fluoxetine, paroxetine, or sertraline) to improve energy 6
• If anemia or vitamin deficiencies are present, treat according to standard protocols 1, 5
• Consider cognitive behavioral therapy if psychological factors are prominent 5, 6

Nutritional Consultation

• If weight changes or dietary imbalances are identified, consult with a nutrition expert 4, 5
• Address any electrolyte imbalances with appropriate supplementation 4

Follow-Up Strategy

• Schedule regular follow-up visits rather than sporadic urgent appointments for effective long-term management 6
• If initial laboratory results are normal and diagnosis remains unclear, practice watchful waiting to prevent overdiagnosis 3
• Avoid an exclusively somatic focus, as this can lead to excessive testing and missed psychological causes 3