Drinking too much caffeine can show up as fatigue, jitters, headaches, heart palpitations, and more. Experts recommend capping your caffeine intake at 400 milligrams a day. If you spot these warning ...

Nick Blackmer is a librarian, fact-checker, and researcher with more than 20 years of experience in consumer-facing health and wellness content. Drinking too much caffeine can show up as fatigue, ...