Beyond those with an unintentional inability to sleep, millions more Americans undersleep by choice, burning the candle at both ends because of hectic work and family schedules.

• 除去那些有睡眠障碍的人，美国有数百万人主动选择放弃睡眠，忙碌的工作和紧凑的生活节奏使他们不得不拼命透支自己的精力。