镉对心脏和其他很多器官都有毒性，根据美国食品药物监督管理局的规定，人体接触镉的阈值很低（每天每公斤或每2.2磅体重0.21-0.36微克）。摄入可能引起胃部不适、恶心和呕吐。

Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient world slept only 6.5 hours a night.