What Does the Clock Change Do to Your Sleep and Heart?

Do you feel wrecked for days after the clocks change, and does it matter for your heart? Here is what research on daylight saving time, sleep and heart health shows, what it cannot show, and a 7-day plan to adjust.

In this article

1. What does the clock change do to your sleep?
2. Do heart attacks rise after the spring clock change?
3. What about the autumn change?
4. What is the AASM position on permanent standard time?
5. How can you adjust when the clocks go back?
6. What should you track in the week after the change?
7. Who should be careful after a clock change?
8. Frequently asked questions
9. Final thoughts
10. Sources and further reading

What does the clock change do to your sleep?

A one-hour clock change shifts the time on the wall but not your internal body clock, so sleep timing and sleep amount can drift for several days. The Sleep Foundation describes this as a disruption of the circadian rhythm, with the spring change usually felt more than the autumn one.

Lost sleep is the best-documented effect. The Sleep Foundation cites research showing the average person gets about 40 minutes less sleep on the Monday after clocks move forward in spring.

When do the clocks change in 2026?

Dates differ by country, so check your own. GOV.UK says UK clocks go back one hour at 2am on the last Sunday in October, which is 25 October in 2026. The Sleep Foundation lists 1 November 2026 for the United States, where clocks go back at 2am local time.

An unsettled week can also feel stressful, and the effects of strain on your pulse are covered in how stress affects your heart rate.

Do heart attacks rise after the spring clock change?

Several observational studies report a small, short-lived rise in heart attack admissions in the days after the spring clock change. The increase is modest, the studies cannot prove the clock change caused it, and the chance that any one person is affected is low.

Sleep loss is the leading explanation put forward. The 2019 meta-analysis authors suggest disrupted circadian rhythms may raise sympathetic nervous system activity, inflammation, heart rate and blood pressure. That is a hypothesis, not a demonstrated chain of cause.

The Jiddou study

Jiddou and colleagues reviewed records from Michigan hospitals between October 2006 and April 2012, comparing heart attack admissions in the week after each clock change. Published in the American Journal of Cardiology in 2013, it reported an incidence ratio of 1.17 for the first week after the spring change, with the biggest rise on the first day.

The Sandhu study

Sandhu and colleagues analysed 42,060 admissions for heart attacks needing a stent procedure across Michigan hospitals between 2010 and September 2013. Comparing the Monday before the spring change with the Monday after, they counted 93 admissions versus 125 across four years of data. The study appeared in Open Heart in 2014.

The weekly total of heart attacks did not change, so some events may have shifted in time rather than increased. The study covered one state and only stent-treated heart attacks, and the researcher said causation could not be established.

What the pooled data show

A 2019 meta-analysis by Manfredini and colleagues in the Journal of Clinical Medicine pooled seven studies covering more than 115,000 people. The spring transition was linked with a small rise in heart attack risk (odds ratio 1.05, 95% confidence interval 1.02 to 1.07). The authors called the increase modest but significant, and noted intermediate to high heterogeneity between studies.

What about the autumn change?

The autumn clock change appears to carry less heart risk than the spring one, but the evidence is thinner and not entirely consistent. The 2019 meta-analysis found no clear change in heart attack incidence in the week after the autumn shift, while one Michigan study noted fewer admissions on a single day.

In the meta-analysis, the week after the autumn transition looked comparable with control periods (odds ratio 1.01, 95% confidence interval 0.98 to 1.04).

In the Sandhu study, admissions on the Tuesday after the autumn change were 21 percent lower. This was a single day in one state, so treat it as an interesting pattern rather than a benefit you can rely on.

Why the extra hour is not a free gift

The body clock does not shift instantly, so you may wake early by the clock and feel sleepy early in the evening. The Sleep Charity advises keeping a routine close to your usual one rather than sleeping in.

Early waking can feel groggy for a while, as covered in what sleep inertia is and why the first 30 minutes are so groggy.

What is the AASM position on permanent standard time?

The American Academy of Sleep Medicine says the United States should eliminate seasonal time changes and adopt permanent standard time. The position, published in the Journal of Clinical Sleep Medicine in October 2023, argues that standard time aligns best with human circadian biology and the rising and setting of the sun.

HealthDay reported that the AASM Public Safety Committee chair said daylight saving time raises risks to physical health, mental well-being and public safety by misaligning the body clock with the natural environment. About 20 other health organisations, including the National Sleep Foundation, backed the updated statement.

How can you adjust when the clocks go back?

You can adjust by shifting bedtime and wake time in small steps before the change, getting outdoor light in the morning afterwards, and keeping a regular routine. UK and US sleep organisations suggest steps of about 10 to 20 minutes a day rather than one big jump.

The Sleep Charity suggests going to bed and getting up 10 to 15 minutes later each day in the week before the clocks go back. It also recommends spending at least 20 minutes outdoors each morning, even on cloudy days, to help reset the body clock.

What should you track in the week after the change?

Tracking a few simple signals in the week after the clock change shows how quickly your own body adapts. Useful signals include bedtime, wake time, how rested you feel and, if you have a device, resting heart rate. Compare them with an ordinary week.

How to read your log

Seasonal changes in resting heart rate are a related topic, and whether your resting heart rate changes with the seasons explains what has been reported.

Who should be careful after a clock change?

People with existing heart disease, shift workers, anyone who is pregnant, and people with long-running sleep problems should plan the clock change carefully and ask a clinician for personal advice. General research findings describe groups of people and cannot say what will happen to you.

Heart warning signs

The NHS lists the signs of a heart attack as chest pain that may feel crushing or squeezing and can spread to the arm, neck or jaw, along with shortness of breath, nausea and sweating. It advises calling 999 straight away and not driving yourself to A&E. In other countries, call your local emergency number.

Frequently asked questions

Does daylight saving time cause heart attacks?

No study has proved that it does. Observational research links the days after the spring change with a small increase in heart attack admissions, but it cannot show cause. The 2019 meta-analysis called the increase modest, and the absolute chance for any one person remains low.

How long does it take to adjust to the clock change?

It varies, but many people feel settled within several days. The Sleep Foundation reports about 40 minutes less sleep on the Monday after the spring change on average, and the Sleep Charity compares the shift with mild jet lag. A regular routine and morning light can help.

Is it worse to lose an hour or gain an hour?

Losing an hour in spring appears worse. The Sleep Foundation says the November change typically causes fewer problems, and the 2019 meta-analysis found no clear rise in heart attacks after the autumn change. The autumn evidence is thinner, though, so the picture is not settled.

What does the American Academy of Sleep Medicine recommend?

The AASM recommends that the United States eliminate seasonal time changes and adopt permanent standard time. Its updated 2023 statement, published in the Journal of Clinical Sleep Medicine, says standard time aligns best with human circadian biology. About 20 other health organisations backed the position.

Should I go to bed earlier or later before the clocks go back?

The Sleep Charity suggests going to bed and getting up 10 to 15 minutes later each day in the week before the October change. For the spring change, the Sleep Foundation suggests moving bedtime 15 to 20 minutes earlier for two or three days.

When should I see a doctor about sleep after a clock change?

See a doctor if poor sleep lasts more than a week or two, if you have loud snoring or gasping at night, or if daytime sleepiness affects driving or work. Seek emergency help immediately for chest pain, severe breathlessness or other heart attack warning signs listed by the NHS.

Final thoughts

Here is the short recap.

• The spring change costs many people sleep and is linked with a small rise in heart attack admissions, but the evidence is observational and the individual risk is low.
• The autumn change looks gentler, though gaining an hour can still shift your body clock for a few days.
• Small daily shifts in bedtime, morning daylight and a steady routine are the most commonly recommended ways to adjust.

Your turn: How long does it usually take you to feel normal after the clocks change, and what helps most? Tell us in the comments.

Sources and further reading

1. Sleep Foundation. Daylight Saving Time. sleepfoundation.org, accessed 2026.
2. HealthDay. Clocks 'Fall Back' on Sunday. U.S. Sleep Experts Want No 'Spring Forward'. Report on the American Academy of Sleep Medicine position statement, Journal of Clinical Sleep Medicine, 31 October 2023.
3. Manfredini R, et al. Daylight Saving Time and Acute Myocardial Infarction: A Meta-Analysis. Journal of Clinical Medicine, 2019.
4. American College of Cardiology. Daylight Saving Impacts the Timing of Heart Attacks. Press release on Sandhu et al., Open Heart, 2014.
5. Jiddou MR, Pica M, Boura J, Qu L, Franklin BA. Incidence of myocardial infarction with shifts to and from daylight savings time. American Journal of Cardiology, 2013 (Europe PMC record).
6. The Sleep Charity. How to prepare for the October clock change and protect your sleep this winter. thesleepcharity.org.uk, accessed 2026.
7. GOV.UK. When do the clocks change?. gov.uk, accessed 2026.
8. NHS. Heart attack. nhs.uk, accessed 2026.