How Daylight Saving Time Affects Your Health

How Daylight Saving Time Affects Your Health

Every year, millions of Australians wind their clocks forward or back for daylight saving time (DST). It might seem like a minor one-hour change, but research shows it can affect your sleep, heart, mental health, and even safety. Let’s take a look at what DST does to your body—and why health experts are concerned.

What Is Daylight Saving Time?

Daylight saving time means we move the clock forward by one hour in spring and back again in autumn. The goal is to create longer daylight hours in the evening.

In Australia, DST is observed in New South Wales, Victoria, South Australia, Tasmania, and the ACT. It is not observed in Queensland, Western Australia, or the Northern Territory.

How DST Can Harm Your Health

1. Sleep Disruption

Even a single hour can disturb your body’s internal clock, known as the circadian rhythm. After the spring change, people often experience shorter and poorer-quality sleep.

This can lead to:

• Daytime drowsiness
• Trouble focusing
• Mood swings
• Lower work performance

Those who already struggle with sleep—like shift workers or people with insomnia—feel it the most.

📖 Read the 2020 review in Sleep Medicine Reviews

2. Higher Risk of Heart Attacks and Strokes

Heart problems spike after the clocks go forward. A 2013 study found a 10% increase in heart attacks right after the DST shift. Experts believe the mix of sleep loss and stress plays a key role.

Stroke risk also rises. A 2021 review found that older adults and cancer patients are more likely to have a stroke in the first two days after DST begins.

📖 Read the heart study in The American Journal of Cardiology
📖 Read the stroke study in Journal of Clinical Sleep Medicine

3. Mood and Mental Health

DST affects your exposure to natural light. That matters because light influences brain chemicals tied to mood and sleep.

DST has been linked to:

• Higher depression rates
• Worsening of seasonal affective disorder (SAD)
• Increased suicide risk in vulnerable people

Even small shifts in your light-dark cycle can throw off hormone balance and emotional wellbeing.

4. More Accidents and Injuries

Lack of sleep slows reaction times and impairs judgment. After DST begins, research shows:

• A rise in car crashes, especially in the early morning
• A jump in workplace injuries, particularly in jobs involving machinery or physical risk

Are There Any Health Benefits?

Some people enjoy more daylight in the evening and might spend more time outside. That could boost physical activity for some.

But the research shows that these benefits don’t outweigh the risks, especially in the week following the time change.

Who’s Most at Risk?

DST affects most people, but these groups are hit harder:

• People with existing sleep problems
• Older adults
• People with heart conditions or high stroke risk
• Shift workers
• Children and teens (who often don’t get enough sleep already)

Tips to Protect Your Health During DST

If your state observes DST, try these simple steps:

• Shift your bedtime earlier by 15–30 minutes for a few nights before the change
• Get morning sunlight to help your body adjust
• Avoid caffeine and screens before bedtime
• Stick to a consistent routine, even on weekends
• Be extra careful driving or working during the first few days after the change

Should We Scrap Daylight Saving Time?

Many researchers say yes. Permanent standard time—keeping clocks the same all year—aligns better with our natural body clocks and supports healthier sleep patterns.

Some governments are already exploring this idea. In Australia, it would require national agreement across states and territories.

Final Thoughts

Daylight saving time was designed to give us more usable daylight. But science now shows it may be doing more harm than good. From disturbed sleep to increased risk of heart issues and mental health problems, the toll is real.

You can take steps to prepare—but long term, many experts believe we should stop changing the clocks altogether.

References

• Lahti, T., & Merikanto, I. (2020). Daylight saving time transitions and sleep. Sleep Medicine Reviews, 52, 101308.
  🔗 https://pubmed.ncbi.nlm.nih.gov/32844740/
• Janszky, I., & Ljung, R. (2013). Shifts to and from daylight saving time and incidence of myocardial infarction. The American Journal of Cardiology, 111(5), 631–635.
  🔗 https://pubmed.ncbi.nlm.nih.gov/23477947/
• Manfredini, R., et al. (2021). Daylight saving time and acute cerebrovascular events: A systematic review. Journal of Clinical Sleep Medicine, 17(8), 1689–1698.
  🔗 https://pubmed.ncbi.nlm.nih.gov/34325828/