How Daylight Saving Time Affects Your Health

Quick Summary: Daylight Saving and Your Health

Q: Does daylight saving time affect sleep?
A: Yes, it can disrupt your body clock, reduce sleep quality, and cause fatigue.

Q: Can DST increase health risks?
A: Research shows a higher risk of heart attacks and strokes right after the spring time change.

Q: Does it impact mental health?
A: Yes, DST has been linked to increased depression and mood disturbances.

Q: Who is most affected?
A: Older adults, people with heart disease, shift workers, and those with sleep disorders.

Q: What can I do to cope?
A: Gradually adjust your sleep schedule, get morning sunlight, and maintain a steady routine.

Each year, millions of Australians adjust their clocks for daylight saving time (DST). While it might seem like a simple one-hour shift, growing research shows that DST can significantly impact our health. From disturbed sleep to increased risk of heart issues, this article explores how daylight saving time affects your body and why we should take it seriously.

What Is Daylight Saving Time?

Daylight saving time is the practice of setting the clock forward by one hour in spring and moving it back in autumn. The goal is to extend daylight in the evenings, reducing the need for artificial lighting.

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

How Does DST Disrupt Our Health?

1. Sleep Disruption and Fatigue

Even a one-hour shift can throw off your circadian rhythm—your body’s internal clock. A study published in Sleep Medicine Reviews (2020) found that the spring transition to DST results in shorter sleep duration and worse sleep quality, especially in the days following the time change .

This sleep loss can lead to:

  • Daytime tiredness

  • Difficulty concentrating

  • Mood changes

  • Lower work productivity

And for shift workers or those with pre-existing sleep disorders, the effects can be even more pronounced.

2. Increased Risk of Heart Attacks and Strokes

According to a 2013 study published in The American Journal of Cardiology, the risk of heart attacks increases by 10% in the days following the spring DST change . This may be due to the combination of sleep loss, circadian misalignment, and increased stress.

A similar pattern is seen with strokes. The 2021 study in Journal of Clinical Sleep Medicine found that the risk of stroke is higher in the first two days after the DST transition, particularly among older adults and those with cancer .

3. Mental Health and Mood Disorders

Changes in sleep patterns and reduced morning light exposure can also impact mental health. DST has been associated with:

  • Increased rates of depression

  • Worsening of seasonal affective disorder (SAD)

  • Higher risk of suicidal behaviour, especially in vulnerable populations

The 2020 review highlighted how even small changes in light-dark cycles can influence mood regulation and hormonal balance .

4. Road Accidents and Workplace Injuries

When people are tired, they make more mistakes. In the week after the clocks move forward, studies report:

  • An increase in car crashes, particularly in the early morning

  • A rise in workplace injuries, especially in high-risk industries like construction and manufacturing

Fatigue and slower reaction times can make commuting and working more dangerous right after the DST change.

Are There Any Health Benefits?

There is limited evidence of positive health effects from DST. While some people may spend more time outdoors in the evening, potentially increasing physical activity, these benefits are often outweighed by the adverse health outcomes, particularly during the transition period.

Who Is Most at Risk?

DST may affect everyone, but some groups are more vulnerable:

  • People with sleep disorders

  • Older adults

  • Individuals with heart disease or high stroke risk

  • Shift workers

  • Children and teens (who already tend to get too little sleep)

Tips to Protect Your Health During DST

If you live in a state that observes daylight saving time, here are some ways to ease the transition:

  • Adjust your sleep schedule a few days before (15–30 minutes earlier each night).

  • Get morning sunlight to help reset your body clock.

  • Avoid caffeine and screens close to bedtime.

  • Stick to a consistent routine to help regulate your sleep-wake cycle.

  • Be extra cautious while driving or doing safety-sensitive work in the days after the change.

Should We Get Rid of Daylight Savings Time?

There’s growing support among scientists for abolishing DST. Permanent standard time—where clocks don’t shift—better aligns with our natural body rhythms and is considered healthier overall.

Several countries and states are already debating this change. In Australia, this would require coordinated action between federal and state governments.

Conclusion

While daylight saving time was designed to use daylight better, evidence suggests it may be doing more harm than good to our health. The effects are tangible and measurable, from heart health to mental well-being. Taking simple steps to prepare for the change can help, but many experts believe the best solution is to do away with DST altogether.

References

  1. Lahti, T., & Merikanto, I. (2020). Daylight saving time transitions and sleep. Sleep Medicine Reviews, 52, 101308. [PubMed ID: 32844740]

  2. 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. [PubMed ID: 23477947]

  3. Manfredini, R., et al. (2021). Daylight saving time and acute cerebrovascular events: A systematic review. Journal of Clinical Sleep Medicine, 17(8), 1689–1698. [PubMed ID: 34325828]

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