Clock change and sleep: what shifts and how to adapt

The clock change can affect sleep, but studies are not conclusive about how long or how intense that effect is. In spring, when the clocks go forward an hour, some studies suggest an association with a modest increase in the risk of acute myocardial infarction, especially in the first week after the change, possibly through sleep deprivation and circadian misalignment. You do need some patience, though, and a routine.

One thing should be said upfront: the evidence on the health effects of the clock change is emerging. There are data pointing to risks, and there are institutions calling for an end to seasonal changes, but we do not know everything. This article separates what is reasonably established from what is only suspicion.

When the clocks change in Portugal

What matters for sleep is not the date itself, but the consistency of the time you fall asleep and wake up. In spring, the clock goes forward an hour and the body may not have time to adjust straight away. In autumn, the clock goes back an hour, but the body still needs to reorganise. The review we found associates the clock change with a modest increase in acute myocardial infarction, especially in the first week after the spring forward, but this association is not established.

Why the clock change leaves us so flat

Consistency in the times you fall asleep and wake up is important for health, safety and performance, according to a National Sleep Foundation consensus. When the social timetable shifts suddenly, the consistency of that rhythm can be affected.

The American Academy of Sleep Medicine (AASM) goes further and states that accumulated evidence indicates the transition from standard time to daylight saving time carries significant public health and safety risks, including a higher risk of adverse cardiovascular events, mood disturbances and traffic accidents. It therefore advocates abolishing seasonal changes. That is an institutional position, not a universal consensus on the best solution, but it is clear and based on data.

There are also reviews that found an association between the clock change and a modest increase in acute myocardial infarctions, especially in the first week after the spring forward. The most likely explanation involves sleep deprivation and circadian misalignment. Note the word association: it does not mean the clock change causes a heart attack in a healthy person. It means that, in a large population, the numbers rise slightly on those days. If you have a known heart condition, this is a reason to be extra careful, not to panic.

How long adaptation takes

There is no magic number that applies to everyone. If you keep waking in the middle of the night, falling asleep very late or feeling exhausted during the day, it is worth looking at that calmly. That is another matter, and it is worth looking at calmly.

What to do in the days before and after

Consistency matters. A National Sleep Foundation consensus document concluded that regularity in the times you fall asleep and wake up is important for health, safety and performance. This applies all year round, but it is especially useful around the clock change.

Specifically, in order of what tends to work best:

• Start the change a few days early. In the three to four days before the spring transition, go to bed and wake up 15 to 20 minutes earlier than usual. In autumn, do the opposite: shift slightly later, so the body does not notice the new time so much. It is not an exact science, but it softens the blow.
• Get natural light in the morning. Go outside or at least open the curtains soon after waking.
• Keep your wake-up time fixed, even at the weekend. It may be hard on the Sunday of the change, but it stops the misalignment dragging on.
• Create a helpful environment. The UK National Health Service suggests a regular routine, a quiet, dark, cool bedroom, and avoiding screens in the hour before bed. These are simple, cheap measures worth adding to your routine.
• Cut caffeine after lunch and alcohol in the evening.

You do not need to do all of it. Pick two or three of these measures and stick to them for a week. Done half-heartedly, they are worth little.

What usually does not help

Plenty of popular advice does not stand up to the evidence. Consistency in the times you fall asleep and wake up is important for health, safety and performance, according to a National Sleep Foundation consensus.

It is also not worth trying to "catch up" on the lost hour all at once by sleeping for ten hours on Sunday. What helps is regularity, not a one-off excess. And be wary of anyone promising a definitive solution to the clock change: there isn't one, because the problem is not a lack, it is a temporary mismatch between your body clock and the clock on the wall.

Where supplements honestly fit

Here the evidence is emerging, and it is best not to overstate it. Sleep Well Gummies provide 1 mg of melatonin per serving of two gummies, for adults, to be chewed shortly before bedtime. Read the label and respect the dose; it may cause drowsiness, so you should not drive or operate machinery after taking it.

Ashwagandha, L-theanine, GABA and vitamins D3 and B12 are the active ingredients in Stress Relief Gummies, but the pack does not cover any effect of these ingredients on adapting to the clock change. Stress Relief Gummies combine ashwagandha extract, L-theanine, GABA, vitamin D3 and vitamin B12, and are intended for adults; they are not recommended for children, pregnant or breastfeeding women, or people with thyroid or autoimmune diseases, and caution is required in case of liver disease or when taking medication. They may cause drowsiness.

A supplement does not replace regular hours, morning light and a dark bedroom. If you expect a bottle to solve the clock change on its own, you will probably be disappointed.

None of this is treatment. If your problem is persistent insomnia, that is a different conversation and belongs with a doctor or pharmacist, not a bottle of gummies.

When this stops being normal

There are signs, however, that deserve a conversation with a healthcare professional: insomnia that drags on for weeks, intense daytime sleepiness that interferes with work or driving, chest pain, palpitations or shortness of breath, marked mood changes, or tiredness that gets worse instead of better. If you have a known heart condition, talk to your doctor about the week of the clock change, especially in spring.

It is also worth seeking help if you snore a lot, wake with a dry mouth or your partner notices pauses in your breathing. That is not the clock change; it is something else that deserves to be looked at.

A realistic plan for the week of the change

In the three days before, adjust your bedtime by 15 to 20 minutes. On the night of the transition, go to bed at the new time, not the old one. The next day, get out into daylight first thing in the morning, even if it is hard. During the week, keep your wake-up time fixed and avoid long naps. After seven to ten days, take stock: if your sleep is stable, your body has done its job. If it is not, the problem probably existed before the clocks changed, and that is where you should focus your attention.

The evidence on the long-term effects of the clock change is still being built. What we do know safely is useful: keeping regular sleep hours and a dark, cool bedroom helps protect your sleep.