I recently had a couple inquiries about people with Down syndrome in their 50s or 60s who developed increased fatigue and falling asleep easily (these were new symptoms). Source: Brian Chicoine, MD Tags:Addison's diseaseagingAlzheimer's Diseaseanemiabrain injuryCancerceliac diseasedepressiondiabetesfalling asleepfatigueGiardiaheart diseasehyperthyroidismhypothyroidismmetabolic conditionsnarcolepsyRefluxseizuressleep apneasleep problemstestosterone deficiencytiredVitamin deficiency