The Effects of Daylight Saving Time on Sleep
On 27th March our clocks go forward an hour in line with Daylight Saving. We often think of this as the true start of spring and are grateful for the lighter evenings but have you ever wondered how this change affects your sleep?
You might think the only way the change to DST impacts your sleep is by making it an hour shorter for one day. But the truth is you’re more likely to have trouble falling, and staying, asleep and this can last for up to a week or much longer after the change.
When the clocks go forward and you wake up an hour earlier than usual — and go about your day eating, working, and exercising an hour earlier than usual — your body experiences a kind of jet lag. You won’t living in sync with your circadian rhythm, the internal clock that dictates our energy levels over a roughly 24-hour cycle.
One of the things that your circadian rhythm controls is when your body feels awake and when it feels sleepy so when it’s out of whack it can be harder to fall asleep. That leads to low energy the next day — think grogginess during an important 10 a.m. meeting.
Too many nights like this and you’ll end up with sleep debt. This is the amount of sleep you “owe” your body over the last 14 nights when compared to your sleep need. The amount of sleep you need is genetically determined with the average being 8 hours 10 minutes, plus or minus 44 minutes or so. Although there’s always a chance, you’ll fall in the 13.5% who need 9 hours or more sleep per night.
Sleep debt is one of the biggest factors determining how you feel and perform each day.
Clearly Daylight Saving Time can have a significant impact on us for days, or even weeks to come. Circadian misalignment has been linked to impaired cognition, cancer, workplace injuries, traffic accidents, heart attacks and strokes.
Obviously DST is going to happen whether we like it or not but you can reduce the impact of that lost hour of sleep by having good sleep hygiene and maximising the sleep you DO get. Switch off screens at least an hour before bed. Don’t drink coffee later in the day. Avoid heavy meals at least 3 hours before bedtime. Keep your bedroom cool and dark.