Daylight Saving Time and Hormones: Why That One Hour Throws You Off

Why do we often feel out of balance when the clocks change?

Have you ever noticed feeling out of sync when the clocks change? The reason lies in the delicate interplay between our internal body clocks and the natural cycle of day and night. At the heart of this rhythm is melatonin – often called the “darkness hormone.” It regulates our circadian rhythm and influences sleep, weight, metabolism, mood, and even cognitive performance.

Daylight saving time (DST), practiced in Germany since 1980 and across the EU since 1996, shifts our clocks forward in spring and back in autumn. While intended as an energy-saving measure, the transition disrupts the body’s finely tuned hormonal and circadian systems. Interestingly, during the decades after its introduction, the prevalence of endocrine disorders increased from 5% to almost 20%.

Disturbance of circadian rhythms

The springtime switch to DST effectively “steals” an hour from our day. Mornings become darker, evenings lighter – and our natural sleep-wake cycle struggles to keep pace. We feel tired in the morning, restless at night, and less able to fall asleep. A 2024 US study showed a small but measurable rise in overall mortality during the first eight weeks after the spring change, while mortality actually dropped after the return to standard time in autumn.

Why some suffer more than others

The effects of daylight saving time and the associated circadian shift vary from person to person. Some people adapt easily, particularly shift workers and "night owls" who work late and sleep late, as well as early risers who start their day before 7 a.m. However, many people do not fully adjust to daylight saving time and often experience what is commonly referred to as "social jet lag," which can persist as a chronic condition until the return to standard time in November. This phenomenon is more pronounced among women, 32% of whom report difficulties compared to 19% of men.

Health consequences of the time change

• Sleep disorders and insomnia: When our body clocks are out of sync, it can lead to significant sleep disturbances and even insomnia. Women are more prone to sleep disorders due to hormonal fluctuations during certain phases of the menstrual cycle.
• Heightened stress responses: Sleep disturbances can trigger a heightened stress response, which manifests as elevated cortisol levels. This is particularly evident in women, who tend to have a higher cortisol response to stress than men.
• Cardiovascular risks: Studies have shown an increase in heart attacks and other cardiovascular events during the transition to daylight saving time, likely due to disrupted sleep patterns and increased stress.
• Mood disorders: Altered light exposure may affect mood and potentially lead to an increased incidence of depression and other mood disorders during daylight saving time transitions.
• Cognitive and performance impairments: Lack of sleep and unsynchronized circadian rhythms can lead to reduced cognitive function, productivity, and creativity.
• Metabolic disturbances: The time change can disrupt metabolic processes, which can lead to higher blood sugar levels and changes in the hormones that control hunger and satiety.

Tips for better handling of daylight saving time

• Maintain regular sleep patterns : Try to go to bed and wake up at the same time every day.
• Limit alcohol and caffeine : Avoiding alcohol before bedtime can improve sleep quality, and limiting caffeine intake, especially in the afternoon and evening, can make it easier to fall asleep.
• Morning exercise : A morning walk or light exercise can help reset your body clock and improve alertness.
• Short naps : If you feel tired during the day, a short nap of 20 minutes or less may be more helpful than caffeine.

Conclusion

Daylight saving time may give us longer evenings, but it also takes a toll on our sleep, stress levels, heart health, and overall wellbeing. By understanding how the shift impacts our body and taking simple steps to adapt, we can reduce the negative effects. Whether or not DST remains part of our lives, one thing is clear: protecting circadian health is essential for long-term hormonal balance and vitality.

FAQs:

1. What is the main purpose of daylight saving time?
   • Daylight saving time was originally introduced to make better use of daylight during the longer days of the year and to save energy.
2. Can daylight saving time affect mental health?
   • Yes, disruption of circadian rhythms and sleep patterns can affect mental health and increase the risk of mood disorders.
3. Are there any long-term health effects associated with the time change?
   • Long-term effects can include chronic sleep deprivation, increased stress levels, and possible worsening of cardiovascular and metabolic diseases.

For more information about daylight saving time and its health effects, check out the following resources: Save Standard Time , American Academy of Sleep Medicine .