Total daytime sleep: how much is too much

They nap magnificently and the nights are a disaster, and everyone tells you that good days make good nights. Sometimes. Past a certain point, day and night are competing for the same finite amount of sleep.

4 min read

A baby has a total sleep need across twenty-four hours. It is a range rather than a number, it changes with age, and it does not expand because you would like it to. Sleep taken during the day comes out of that same total, which is why the phrase “sleep begets sleep” is only true up to a point and misleading after it.

The point where it flips is roughly where daytime sleep starts leaving too little pressure for a full night. Past that line, another hour of napping does not add an hour of sleep - it moves an hour out of the night and usually breaks it into pieces on the way.

Rough totals to check against

How to redistribute

Add up three days honestly first, naps and night both. Most people find the answer surprising in one direction or the other, and the arithmetic tends to settle arguments that impressions cannot.

If the day portion is above the range and nights are broken, cap the longest nap by fifteen or twenty minutes and hold it for four or five days. Small and slow. Cutting an hour at once produces an overtired baby who wakes more, which is the exact outcome you were trying to avoid and it will look like proof that the theory is wrong.

Sleep begets sleep, right up until the day starts borrowing from the night.

When “let them sleep” is the wrong instinct

After a bad night, the temptation is to let the naps run long to catch up. For a single day that is reasonable. Done for a week it builds a cycle: long naps, low pressure at bedtime, a fragmented night, more long naps. Breaking that cycle usually means one deliberately capped day and an early bedtime, which is uncomfortable for about forty-eight hours and then works.

The exception is illness. A baby who is unwell needs more sleep and should have it - the totals above describe a well baby in an ordinary week, and there is no reason to defend a schedule against a virus.

Doing the arithmetic honestly

Three days, written down as you go rather than reconstructed in the evening. Every nap with a start and an end, and the night with the actual times rather than the intended ones. Most people find one of two things: either there is considerably more daytime sleep than they thought, or the night is shorter than they believed because they were counting time in the cot rather than time asleep.

Both findings are useful and neither is available from memory. It is also worth doing again every couple of months, because the numbers move - a total that was right at six months is too much at nine, and the excess shows up in the night rather than the day.

Where to take the sleep from

If the day total needs reducing, take it from the last nap first. Shortening the afternoon or late nap increases the pressure available at bedtime, which is where you want it. Cutting the morning nap instead tends to produce an overtired child by lunchtime and a worse afternoon.

Fifteen to twenty minutes at a time, held for four or five days before judging. And watch bedtime rather than the night - if bedtime is getting easier, the direction is right, even if the night has not changed yet. Night waking is usually the last thing to respond.

When to stop troubleshooting

Sleeping substantially more than these ranges and still seeming tired, being difficult to rouse, or a sudden increase in total sleep, are all worth raising with your GP. So is the opposite: consistently sleeping far below the range, with irritability and poor weight gain.

General guidance, not medical advice. Your paediatrician's advice takes precedence.