Caffeine Jitters
Like all teas, green tea contains caffeine, and excessive caffeine intake can lead to nervousness, anxiety, abnormal heart rhythm and shakiness. Some people have a low tolerance for caffeine, and they will suffer these symptoms even when ingesting small amounts. High caffeine consumption can also hinder calcium absorption, affecting your bone health and increasing the risk of osteoporosis, a condition in which bones grow brittle and may fracture easily. To help prevent caffeine-related problems, limit green tea intake to five or fewer cups per day