Implications to health as Israel to begin daylight saving time

On the wee hours of Friday, Israel will switch to daylight saving time, moving clocks forward. At 02:00 AM, clocks will jump to 03:00 AM, resulting in the loss of one hour of sleep. While this change provides longer daylight hours in the evening, allowing for extended time after work or school, it’s not just a matter of convenience. The shift can also impact our health.

Dr. Michal Ronen, a specialist in family medicine at Clalit Health Services in Jerusalem, explains: “This change gives us longer daylight hours, but it disrupts our biological clock—the circadian rhythm, which regulates sleep cycles, wakefulness, and other physiological processes. One of the central challenges of switching to daylight saving time is the loss of an hour of sleep on the first night. For individuals sensitive to changes in sleep patterns, this may lead to fatigue, difficulty falling asleep, and concentration issues in the days following the transition. Children and those with consistent sleep schedules may experience a sharper adjustment period.”

Dr. Ronen notes that the good news is that the longer days and extended sunlight can improve mood. Exposure to daylight contributes to the secretion of serotonin, a neurotransmitter linked to feelings of calm and happiness, and may reduce the risk of seasonal affective disorder (SAD), which often occurs during the darker winter months.

Additionally, the extended daylight hours increase exposure to sunlight, which aids in the production of vitamin D. This vitamin is essential for bone health, strengthening the immune system, and regulating metabolism. Dr. Ronen points out that natural sunlight in the morning also enhances alertness and better regulates melatonin secretion, the hormone responsible for sleep.

The longer daylight hours also encourage physical activity in the afternoon and evening, which can improve overall health. However, the clock change can temporarily disrupt appetite patterns, leading to hunger at unusual times until the body adjusts. For individuals who wake up early, whether by nature or necessity, the transition may pose a challenge as their day starts in darkness, requiring a longer wait for sunrise.

Dr. Miriam Fink-Lavi, a child and adolescent psychiatrist and director of mental health services at Leumit Health Services in Jerusalem, emphasizes that any change to the clock, even by just one hour, affects the body. The transition to daylight saving time creates a temporary sleep deficit, which can lead to fatigue, irritability, and restlessness. Studies even indicate a temporary increase in traffic accidents following the time change. According to Dr. Fink-Lavi, during challenging times characterized by sleep difficulties and delayed bedtimes, losing an additional hour of sleep can exacerbate the situation, resulting in heightened fatigue and errors due to lack of concentration.

Dr. Fink-Lavi explains that sleep is crucial for both physical and mental health, playing a vital role in the development of children and adolescents and supporting physical and mental recovery in adults. In recent years, there has been a trend of reduced sleep duration, with many people sleeping less than they need. This can impair concentration, increase irritability, and lead to more mistakes. Adults require about seven hours of sleep per night, but many fail to achieve this due to prolonged screen exposure, especially near bedtime.

During periods of tension, such as during war, sleep disturbances worsen, accompanied by increased screen use, particularly at night. Many people—both teens and adults—tend to sleep with their phones nearby, checking notifications and consuming news content, which disrupts sleep continuity and worsens fatigue. Over the past year and a half, there has been a rise in demand for calming medications and sleeping pills, reflecting widespread struggles with anxiety, stress, and sleep difficulties.

Dr. Fink-Lavi offers several recommendations to help the body adjust to the time change and maintain health:

Dr. Shahar Robinson, head of mental health at Maccabi Health Services in the southern district, says that for most people, the one-hour shift causes only temporary fatigue. However, in the week following the start of daylight saving time, fatigue becomes a common phenomenon. For a small portion of the population, the change can be much more significant. “When it comes to an entire country, even a ‘small percentage’ translates to a significant number of people who struggle with adaptation,” he explains.

Dr. Robinson notes that the transition to daylight saving time is more challenging than the return to standard time because it robs us of an hour of sleep. Additionally, it alters the day-night cycle, which can disrupt or worsen existing sleep disorders. For those already struggling with mood disorders or chronic illnesses, the shift can lead to worsening symptoms.

Dr. Erel Domany, a senior neurologist and head of the Headache Clinic at Rambam Health Care Campus, explains that "time changes, including the transition to daylight saving time, can affect individuals with migraines or chronic headaches. Migraine sufferers are particularly sensitive to changes in sleep schedules and light-dark cycles, which can trigger episodes. Additionally, cluster headache patients, who often experience seasonal flare-ups, may see a worsening of symptoms around time changes."

Research has also indicated an increase in the incidence of strokes and seizures among epilepsy patients during the week following a time change, likely due to disruptions in biological rhythms and sleep quality. Dr. Domany adds that individuals with dementia or Alzheimer’s may also face greater difficulties during this period, both in sleep and daily functioning. While most people won’t require medication, melatonin may be helpful in some cases under a doctor’s guidance.

The transition between standard time and daylight saving time is often compared to jet lag experienced simultaneously by an entire population. It’s as though the entire country went to sleep in Israel and woke up in Italy or Dubai—without the vacation.