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Daylight saving - what's it all about anyway? And how to avoid feeling tired when the clock go forward


During the daylight-saving months we are on ‘New Zealand daylight time’, which is 1 hour ahead of New Zealand standard time.

These dates and the time of the change are heavily publicised in the lead up to the change through television and radio advertisements, local council websites and national newspapers. So how come it always takes me by surprise? And how come I never know if that means MORE sleep or LESS sleep each time the clocks change?

The rationale for changing the time over the summer months is that more sunlight hours will fall in the early morning if standard time is applied year-round. In summer, these early morning sunlight hours are seen as being wasted as many people are asleep at that time. If the sunlight hours are shifted to the evening, by way of daylight- saving time, they are more useful. Keeping up so far? Good. Carry on.

Public attitudes to daylight saving in New Zealand

A 2008 survey found that 82% of New Zealanders approved of daylight-saving time.

Research New Zealand surveyed 1006 members of the public. The survey was conducted between 8 and 29 April 2008 after daylight saving ended. The survey was designed to measure the impact of the extended period of daylight saving on New Zealanders.


  • The extension to daylight saving was approved of by 82% of respondents, with 57% strongly approving. In contrast, 5% disapproved and 6% strongly disapproved.

  • Just over half of respondents (52%) believed the extension to daylight saving had a personal impact on them, with 47% believing it had no impact on them.

  • Respondents who believed the daylight-saving extension had had a personal impact on them were more likely to say that these impacts were positive. Expressed as a proportion of the total sample, 31% of respondents claimed that the impacts on them were all positive, 5% claimed they were all negative, and 14% claimed the impacts were both positive and negative. About half (49%) believed the extension had neither a positive nor negative impact (including the 47% noted above who reported no personal impact at all).

  • Daylight saving in general was approved of by 90% of all respondents, with 72% strongly approving. In contrast, 6% disapproved.

Since its inception, there has been much debate over the pros and cons of daylight-saving. Organisations that research sleep care are critical of daylight saving time, particularly the effect it has on public health and safety. They point to studies which indicate it increases the risk of heart-related problems, mood disorders, and motor vehicle accidents.

Take, for example, the European Biological Rhythms SocietyEuropean Sleep Research Society, and Society for Research on Biological Rhythms. These 3 societies issued a joint statement to the EU Commission in which they advocated replacing daylight saving time with a standard time. Their statement offered to provide evidence which showed that replacing daylight saving time would reduce the incidence of cancer, reduce consumption of alcohol and tobacco, and improve performance at school and work. This eventually led to the EU Parliament voting to end daylight saving time in 2021.

Following in the footsteps of these societies, the American Academy of Sleep Medicine adopted the position that the US should do away with daylight saving time in favour of a national, fixed, year-round time that aligns best with human biology.

But how exactly does shifting an hour impact our sleep, as well as our health and safety? In this blog, we’ll attempt to answer that question and explore 3 ways to avoid feeling tired when the clocks go forward.

How daylight-saving affects sleep

To understand how daylight-saving time affects sleep, we first need to understand there are 3 types of clocks: the sun clock, our body or circadian clock, and our social clock.

The sun clock is set by the rotation of the earth around the sun. The light of the sun and the darkness of the night act as signals that set our body clock. Ideally, both these clocks should be in sync. However, our social clock, set by societies, makes this difficult, with work activities and time with friends often requiring us to wake up or go to sleep outside of daylight periods.

Daylight saving time shifts our social clock an hour forward in the summer, which means less morning light and more evening light, and this shift can lead to our body clocks no longer being in sync with the sun clock or day-night cycles. This creates a feeling similar to jet lag.

“but it’s only 1 hour.”

True, it is just 1 hour. But one study found that this hour is capable of throwing our body clock so out of sync that it takes weeks to recover. And during this period, we risk facing a number of consequences including:

  • less sleep (the Monday after the clocks change, people sleep 40 minutes less than they normally would)

  • worse performance (studies show an increase in the number of workplace injuries and traffic accidents the day after the clocks change)

  • worse health (studies show the rate of heart attacks is higher the week after the clocks change compared to other weeks)

Waking up feeling tired because of daylight-saving time can result in real-world consequences. Fortunately, there are plenty of ways by which you can mitigate these negative effects.

How to avoid feeling tired when the clocks go forward

After daylight-saving time, the sun clock, body clock, and social clock are far from in sync. The best thing to do is to focus on resetting your body clock, which is influenced by behaviour, environment, and medications. Listed below are 3 tips for each of these 3 factors, which can help you reset your body clock and avoid feeling tired when you wake up.

1.     Adjust your sleep schedule

The clocks moving forward means more evening light, and greater exposure to evening light can impact our body clock and push our sleep cycle towards a later bedtime.

Counter this by gradually going to sleep an hour before you normally do in the run up to daylight-saving time. That way your body adjusts to waking up earlier and you still get your usual amount of sleep – which should be between 7 to 9 hours.

It’s also worth going out in the morning or exercising early to get more morning light (avoid working out in the evening or 4 hours to bedtime as this can impact your ability to sleep). Day-time exposure to light can help with resetting your inner clock.

Try to avoid long naps in the afternoon, especially after 3 p.m., as that too can impact your ability to sleep. Your sleep is regulated by homeostatic and circadian processes. The former is referred to as process S, and is sleep pressure that builds up during the day. If you take a long nap, or a nap after 3 p.m., then you risk reducing sleep pressure, thereby making it difficult for you to fall asleep at night.

2.      Practice good sleep hygiene

It’s important to know how to sleep well, especially in terms of developing good sleep habits and an ideal sleep environment.

With daylight-saving time resulting in more evening light, consider investing in blackout curtains or an eye mask to ensure you sleep in complete darkness. Furthermore, with people perhaps keen to enjoy spending time out in the evenings while it’s still light, it might be worth getting ear plugs or a white noise machine to ensure you block out sounds and sleep in silence.

Lastly, avoid using electronic devices or consuming alcohol, caffeine, nicotine or any other stimulant just before bed. Electronic devices emit blue light which, while not as powerful as sunlight, can still affect your body clock. Alcohol reduces sleep quality, while caffeine blocks receptors in your brain that help you to fall asleep.

3.      Try safe sleeping and waking supplements

While various medications exist on the market to promote sleep, their side effect profile and addictive potential limit their widespread use. By contrast, the over-the-counter supplement melatonin offers a more tolerable solution, that can help to accelerate sleep onset and sync your circadian clock.

Right, this blog is making me feel sleepy now. I’m off for a nap. See you next month!