Perimenopause Can Begin in Your 30s or 40s, Often Showing Up as Fatigue and Sleep Changes

A Flo Health–Mayo Clinic study of 17,000 women across 158 countries finds that many experience fatigue, exhaustion, sleep disturbances, mood changes, and digestive issues during the perimenopause transition—even before classic hot flashes—while some symptoms cluster in the 30s and 40s. The research highlights a widespread knowledge and diagnostic gap, especially in the US, where symptoms are often attributed to stress or burnout and care is fragmented with limited menopause training. Experts urge tracking menstrual changes alongside mood, sleep, temperature regulation, and digestion, and seeking medical advice early to improve quality of life and potentially prevent longer-term risks such as osteoporosis.