Getting less sleep than a person should can result in a weakened immune system, increasing the chances that one can get sick. Some experts point out that if a person gets only five hours of sleep per night over a period of five days, his or her immune system is weakened by 50%. One study showed that participants who slept fewer than seven hours a night and were then exposed to a cold virus were three times as likely to come down with a cold as study participants who got at least eight hours of sleep per night. 睡眠时间少于正常所需会导致免疫系统变差，从而使你更易生病。一些专家指出如果一个人连续五天以上每天只睡五个小时，那么他或她的免疫系统就会减弱百分之五十。一项研究结果表明，将那些每晚睡眠少于七小时的参与者，暴露在充满感冒病毒的环境下，他们得感冒的几率是那些每晚睡眠八个小时以上参与者的三倍。 More about sleep and illnesses: 更多关于睡眠与疾病的信息： Doctors recommend that the average adult get seven to eight hours of sleep every night. Children and teenagers should get at least nine hours.
During sleep, people produce substances called cytokines that are crucial in fighting off infection. Less sleep means fewer cytokines, increasing a person's susceptibility to illness. 医生建议成年人每晚保证七到八小时的睡眠，而小孩和青少年则应该至少九个小时。在睡眠期间，人类会产生一种被称为细胞因子的物质，这种物质对于抗感冒十分重要。睡眠少以为着细胞因子更少，从而增加了感染疾病的几率。 Adults who oversleep are generally at a greater risk of developing health problems such as obesity, depression and heart trouble. Oversleeping in adults is defined as more than nine or 10 hours per night. 睡眠过多的成人通常极易引发一些健康疾病。如：肥胖、抑郁及心脏病，成人的过度睡眠是指睡眠是指每晚超过九或十个小时。