Lack of good bedtime stories and consumption of fizzy drinks may be the reason why current generation of youngsters do not get the same quality of sleep their grandparents did.
Research by the Sleep Council found that today's seven to 14-year-old children go to bed almost 40 minutes later than their grandparents.
They are also much more likely to snack on crisps and fizzy drinks before bedtime while their grandparents enjoyed cocoa or hot milky drinks such as Horlicks.
If parents ditched the bad habits, bedtime would be less stressful and their offspring would sleep better, experts claimed.
According to the survey - which asked 1,006 grandparents with grandchildren aged seven to 14, to compare their early lifestyle with that of their grandchildren - 21 per cent spent more than three hours each day playing outside.
That compares to the 28 per cent who said their grandchildren now spend less than 30 minutes playing outside on a school day.
Seventy per cent of grandparents ate dinner before 6pm but only 38 per cent of youngsters do so now. Just over half, 51 per cent, eat between 6pm and 7.30pm.
For 95 per cent of the older generation, the evening meal was home cooked but now a quarter of children eat ready-made meals.
"Seven to 14-year-olds still need a good nine or 10 hours sleep a night," the Daily Express quoted Jessica Alexander, of The Sleep Council, as saying.
"Not eating too close to bedtime and avoiding caffeine-fuelled fizzy pop is also important, as is a well balanced diet with plenty of fresh fruit and vegetables," she suggested.