On Sunday morning at 1am, the clocks roll forward one hour, marking the official start of British Summer Time, alias Daylight Savings Time (DST).
Most people will delight in the shift, with more time to get outside in daylight in the evenings.If you are a parent with young children who are waking you up before 6am, this could be just the transition you’ve been waiting for… If you put them to bed at the normal time, you should find that they wake up an hour later.
What’s the downside to DST?
1. Squeezing sleep on top of a ‘Sleep Debt’
Most people sleep in a little longer on the Sunday, so we lose around 40 minutes sleep on average in the switch to DST (Barnes et al 2009).
Does that make a difference? A poor night’s sleep can make us tired and irritable, but we tend to experience deeper sleep the following night as the brain helps us to compensate.
The real challenge comes when a shorter night of sleep is on top of an existing ‘sleep debt’. If you’re routinely getting fewer than 7 to 9 hours of sleep, you may already be running on empty, and this added sleep loss could make you excessively sleepy, which could have dangerous consequences.
A study of 732,000 accidents in the US found that the annual switch to DST is associated with a 6% increase in fatal car crashes that week (Fritz et al 2020).
People also tend to have lower self control when they are tired. One study found that workers are more likely to engage in ‘cyberloafing’ (surfing the internet for entertainment related content) on the Monday after the clock change (Wagner et al 2012).
2. Your body clocks are out of sync with the sun
The biggest challenge of DST is probably not sleep loss, it’s the shift in the timing of light and darkness.
Our bodies rely on lots of little molecular clocks to keep all our internal processes ticking over efficiently. Digestion, heart rate, blood pressure, appetite, immune function, alertness - everything runs on a regular 24 hour cycle of activity and recovery; our circadian rhythm.
Light from the sun, and darkness, helps to keep all of these internal clocks in sync with each other, and with our environment.
Sudden shifts of this internal timekeeping puts the body under stress. It takes most people at least 24 hours for their internal clocks to adjust to waking up an hour earlier. On the Monday after the clock change, one study found a 24% spike in heart attack visits around the US. Other studies have reported more injuries at work, and even an increased risk of suicide.
Some scientists have called for us to ‘ditch the summer switch’, because Standard Time means the light of the sun is better matched to our usual activity patterns around work, school and socialising.
Who is most at risk?
If you are a natural night owl (vs. an early bird), this means your internal clocks run a little slow. Night owls often don’t feel sleepy until at least midnight, and struggle to wake up before 9am.
Night owls will find it harder to cope with shifting their body clocks forward and waking up early in the mornings after the clock change.
Teenagers may find it doubly difficult because few are getting their recommended 8-10 hours of sleep, AND they tend to be night owls, so they would benefit from some deliberate planning…
How to Spring Forward with Ease
1. Start well rested
For any sleep loss, or change to our body clocks, we tend to be more resilient if we’re well rested. Make an effort to wind down before bed, avoid late meals, and dim the lights, to get the best quality sleep you can.
2. Ease into the transition
If you’re reading this before Saturday, you could start to shift your bedtime 20-30 minutes earlier for a few nights before the clock change… So for example, if you usually go to bed at 11, and wake up at 7am:
Thursday, bedtime 10:40pm, wake up at 6:40am
Friday, bedtime 10:20pm, wake up at 6:20am
Saturday, bedtime 10:00pm…
.. which means you’ll be better able wake up at 6am, which really becomes 7am on the Sunday after the clock change. To make it easier to feel sleepy earlier, also move the timing of your evening meal earlier, and dim the lights before bed. Changing meal timing is another handy signal to your internal clocks.
3. Stick to the same wake up time
When it comes to sleep quality, routine is king. If possible, stick to your ‘normal’ weekday wake-up time on Sunday morning. This might mean skipping a lie in, but will make the transition to Monday morning much easier.
If you feel sleepy later in the day, try a 15-20 minute power nap after lunch. If you’re very sleep deprived, you might want to try a longer nap of 60-90 minutes. If you do have a long nap, make it before 3pm, to avoid delaying your body clock, and to allow sleep pressure to build up again before nightfall.
4. Make the most of sunlight
Let’s face it, the big attraction of British Summer Time is the extra light! Getting plenty of exposure to natural daylight helps to keep our internal rhythms in sync. To feel more energised in the mornings, try and get outside for at least 10 minutes in the morning - take your morning cuppa outside, or walk around the block. Sit next to a window to help improve your mood, alertness and concentration.
5. Make it dark at night
It’s darkness that cues the release of melatonin and helps to prepare the brain and body for a restful sleep. As the days get longer, it can be harder to convince yourself to go to bed. This is especially a challenge for children, who will be going to bed in daylight. Blackout blinds or thick curtains are especially helpful in the summer. Use a night light with a low intensity glow if they are scared of the dark. An eye mask can also help if your bedroom is too light.