Every parent knows that getting toddlers to bed on time is a battle. But what if an earlier bedtime could actually help your child grow taller? New research from Japan suggests it might—and it's worth paying attention to, especially for Singapore families juggling busy schedules and competing demands on their time.
What the Research Shows
Scientists studied nearly 50,000 toddlers as part of the Japan Environment and Children's Study, tracking their sleep patterns at 18 months and measuring how much they grew by age 3. The key finding: children who went to bed earlier—between 8pm and 10pm—grew slightly more than those who went to bed after 10pm or 11pm.
The difference wasn't enormous (we're talking a few millimetres over two years), but it was consistent. Children who slept very little overall (less than 11 hours) didn't show this benefit, suggesting that both timing and adequate total sleep matter. Interestingly, how many times a child woke up during the night didn't seem to affect growth—it was the bedtime and total sleep duration that made the difference.
Why Might This Matter?
In Singapore and across Asia, we often hear that children who sleep well do better at everything—school, behaviour, health. This research adds another reason: physical growth. Growth happens largely during deep sleep, especially in the early night hours. When children go to bed earlier, they're more likely to enter that deep sleep phase at optimal times.
For Singapore families, this finding is particularly relevant. Many of us struggle with modern schedules—parents working late, tuition classes, screen time, and the pressure to maximise every waking hour. We might think "it doesn't matter if bedtime is 10pm instead of 8pm, as long as they get their hours." But this research suggests timing really does count.
There's also a practical angle: as the researchers note, bedtime is something you can actually discuss with your child's doctor during routine health checks. It's more controllable than many other factors affecting growth, like genetics or nutrition.
What This Means for Your Family
The study involved Japanese children, so it's worth considering whether findings apply equally in Singapore's tropical climate, different activity levels, and varied family structures. The researchers themselves emphasise this is observational research—it shows an association, not proof that earlier bedtime causes taller growth. Other factors (like family wealth, nutrition, or genetics) could explain some of the difference.
Still, the consistency of the finding across nearly 50,000 children suggests it's worth taking seriously. Combined with everything we already know about sleep benefiting mood, immunity, and brain development, an earlier bedtime looks like a win-win.
Three Practical Steps You Can Take
- Aim for a bedtime between 8pm–10pm for toddlers around 18 months. This appears to be the "sweet spot" in the research. Even if your current bedtime is later, moving it 15–30 minutes earlier each week makes it manageable without sudden resistance.
- Focus on total sleep duration, not just bedtime. The study showed that children sleeping under 11 hours didn't benefit from an early bedtime. Ensure your toddler gets 11–14 hours of total sleep (including naps) over 24 hours.
- Make bedtime a health priority conversation. During your child's regular health checks at the polyclinic or paediatrician, ask about optimal sleep timing. Having professional support makes it easier to justify saying "no" to evening activities that clash with sleep.