In Detail
Persistent fatigue in midlife is rarely caused by a single factor. The most common contributors include hormonal changes (declining testosterone in men, the perimenopausal and menopausal transition in women, undertreated thyroid disease), poor sleep quality (sleep apnea is markedly underdiagnosed, particularly in women), nutritional deficiencies (iron, B12, vitamin D), chronic stress with elevated cortisol, depression and anxiety, and metabolic conditions including insulin resistance.
Medications are an often-overlooked cause. Beta-blockers, certain antidepressants, antihistamines, sleep aids, and others can all contribute to daytime fatigue. A medication review is part of any thoughtful evaluation.
A proper workup investigates these systematically rather than attributing fatigue to age. Many patients have one or two correctable contributors that, when addressed, meaningfully improve daily function.