We lose an hour of sleep on March 29. The mistakes that make adjusting to daylight saving time more difficult and how to avoid them

On Sunday morning, on March 29, 2026, Romania switches to summer time: 03:00 will become 04:00, and we lose an hour of sleep. Sunday will only have 23 hours and, at least for a few days, the body feels it.

The fatigue after the time change is real for many of us, experts say. And in the case of those who were already facing sleep problems, the switch to daylight saving time can exacerbate them. The time change produces an imbalance between the internal biological clock and the social schedule, a phenomenon known as “social jet lag”. The difference is that, unlike jet lag after a transoceanic trip, we're not changing our time zone, but we're forcing our bodies to work on a new, sudden schedule.

An hour of lost sleep is hard to recover

Even if, apparently, we only turn the clocks forward an hour, so we only lose 60 minutes from Sunday, specialists point out that the impact is greater than it seems and that the body needs time to recover.

“The switch to summer time is more harmful to health than the switch to winter time. Our body works according to Standard Time, that is, after winter time, it does not need to change the time with the arrival of spring”, emphasizes Dr. Oana Deleanu, primary pulmonologist with national and European certification in Somnology, head of works at the “Carol Davila” University of Medicine and Pharmacy.

The lost hour can affect the two important parameters of sleep: quantity and quality, experts say. “Opinions about the time needed to recover from lost sleep vary greatly. There are researchers who claim that when it comes to jet lag – when you travel and change time zones – you need a day of adaptation for every hour lost. Other studies hypothesized that after switching to daylight saving time, you need up to two weeks to adapt. The fact is that the body's normal time is Standard Time, that is, winter time. And after switching to summer time, there is a difficult period of adaptation for the body”, explains the specialist in somnology.

In fact, some research has shown that in the first two weeks after the time change, the number of road accidents also increases, which means that the effects are not only subjective.

In order not to deepen the sleep debt accumulated on the night of the time change, Dr. Oana Deleanu recommends, first of all, to prepare the body: try to go to bed 15-20 minutes earlier every night before the time change. And if we can't fall asleep right away, it's important not to enter the vicious circle of thinking “I can't fall asleep,” which makes falling asleep even more difficult, but to choose relaxing activities that promote sleep.

Biggest mistake when you can't sleep: Counting sheep

One of the most common mistakes that many people who have trouble falling asleep make is to stay in bed and “force” sleep. Or count sheep, hoping that way they'll fall asleep.

“The worst thing we can do when we can't fall asleep is to lie in bed and count sheep. Normally, someone with insomnia needs to get out of bed and have a pleasant but non-stressful activity. I give the example of crocheting, origami, an activity that occupies the mind, does not let them ruminate, that is, overthinking about worries and problems, but which can be put aside at any time. In no case do not he starts working for work or cleaning cupboards. Reading can be an option, but not demanding books, but relatively boring. Even the Rubik's cube is not a good idea when we can't fall asleep”, exemplified Dr. Oana Deleanu on the occasion of World Sleep Day, marked on March 13.

Too high a temperature in the bedroom affects sleep

Another mistake that many people make and ruin their sleep without realizing it is setting the temperature too high in the bedroom. The thermostat should be set overnight lower than most would find comfortable. That's because temperatures that are too high seem to shorten the duration of both REM sleep and deep slow-wave sleep, which is responsible for physical recovery. Also, when the bedroom is too hot, the heart has to work harder, in an interval in which it should enter rest and recovery.

According to the Sleep Foundation, the temperature in the bedroom should be between 15.6 and 20 degrees Celsius, with an optimum point around 18.3 degrees Celsius. This recommendation is valid regardless of the season: in winter, the thermostat must be reduced at night compared to the temperature during the day, and in summer, the air conditioning or natural ventilation must reach below 24 degrees Celsius.

The human body operates on a circadian rhythm that also includes a thermal component. The core body temperature, which normally stays around 37 degrees, drops by about 1-1.2 degrees Celsius during the night. This decrease begins about two hours before bedtime and coincides with the release of melatonin, the hormone that signals the body that it is time to sleep. A cool bedroom supports this natural process, while a room that is too warm slows it down or blocks it.

How the body cools down before sleep

Before sleep, the body begins to lower its temperature through a process controlled by the biological clock. Blood flow increases to the extremities, especially the hands and feet, and thus the heat from the inside is more easily lost through the skin. Hence the quite frequent sensation of warm hands or feet in the evening, even when the rest of the body does not seem warm.

According to the Sleep Foundation, people with chronically cold feet are at higher risk of insomnia when falling asleep, likely due to a disruption in this vasodilation mechanism. On the other hand, too cold a room doesn't help either, that's why specialists talk about an optimal range.

Above 24°C, the heart works harder

A study published in BMC Medicine at the end of 2025 analyzed more than 14,000 hours of sleep in real conditions and showed that the temperature in the bedroom directly influences the activity of the heart.

The warmer it was in the room, the higher the heart rate and the lower the heart rate variability (HRV), which shows that the body is not in a recovery process, but stressed. Compared to nights spent in bedrooms with temperatures below 24 degrees Celsius, the risk of clinically low HRV was: 40% higher at 24-26°C; almost double at 26-28°C and three times higher at 28-32°C.

REM sleep, the phase in which the body loses temperature control

Ambient temperature affects sleep phases differently. Studies cited by the Sleep Foundation show that during REM (the stage in which memory is consolidated, mood is regulated, and the ability to focus is maintained), the body almost completely stops sweating or shaking. Basically, the thermoregulation mechanisms stop, and the sleeping person becomes very sensitive to the temperature in the room.

Excessive heat appears to shorten the duration of both REM sleep and deep slow-wave sleep, which is responsible for physical recovery.

One or two bad nights does not mean insomnia

Not every night of less rest is cause for alarm. Occasional episodes of disturbed sleep are normal, especially during times of change such as daylight saving time. “We must not become obsessed with sleep. If we do not sleep well for one or two nights, it is not a tragedy. What is important is what happens in the long term”, emphasizes Dr. Oana Deleanu.

The problem arises when difficulties persist for weeks or months and begin to affect daily functioning, the doctor emphasizes.

How do you know if you slept well: mini-quiz

The pulmonologist and somnologist recommend evaluating several dimensions of sleep with the help of the following questions:

• Did I get enough sleep (between 7 and 9 hours)?
• Did I fall asleep quickly enough (within half an hour of getting into bed)?
• Did I sleep without interruption? It's normal to wake up once or twice during the night, as long as we fall back asleep within minutes.
• When I wake up in the morning, do I feel rested, do I feel satisfied with the night's sleep?
• Am I functional? Am I in shape to get down to business? “Sure, there are some people who, immediately after waking up in the morning, are more dizzy, but then they are functional quickly”, states Dr. Deleanu.

If the answers to these questions are not satisfactory, it would be useful to consult a sleep specialist to identify possible problems that disturb sleep. “There are about 80 sleep pathologies, and sometimes the problems are not only related to the schedule, but to related conditions. Insomnia and sleep apnea are the most common”, says the doctor.