A 15-year-old student's sudden death in class has once again brought into focus the long contentious issue of how much homework is too much for primary and middle school students.

The boy in Nanyang, a city in Central China's Henan province, was said to never have enough sleep, as he could not finish his homework until midnight and had to get up at 6:20 am in the morning.

Too much homework may not necessarily be the direct cause of his sudden death at such a young age. But for those students whose physical constitution is weak, chronic lack of sleep can be a serious risk to their health.