Adapting to Time Changes: Five Essential Tips

While this made sense when we relied heavily on coal for lighting, today the benefits of such a change are contested. Some recent research even suggests that moving the clocks back twice a year has negative effects, particularly on our health.

During the first few days after the time change, many people experience a variety of symptoms: irritability, reduced sleep, daytime fatigue, and decreased immune function. Even more worrying, heart attacks, strokes and workplace accidents are more common in the first weeks after the time change. There was also a 6% increase in fatal car accidents during the week of daylight saving time.

[Un article de The Conversation écrit par Gisela Helfer – Associate Professor in Physiology and Metabolism, University of Bradford]

Why so many difficulties?

If time changes affect us so much, it is because of our internal “biological clock”. This clock controls our basic physiological functions, such as when we are hungry and when we are tired. This rhythm is known as the circadian rhythm and lasts approximately 24 hours.

Our body can't do everything at once, which is why each of its functions has a specific time when it works best.

For example, before we wake up in the morning, our internal clock prepares us for waking up. It stops the pineal gland's production of the sleep hormone melatonin and begins releasing cortisol, a hormone that regulates metabolism. Our breathing also quickens, our blood pressure rises, our heart beats faster, and our body temperature rises slightly.

All this is governed by our internal biological clock, the numerous dials of which are under the control of a “master clock” located in a part of the brain called the hypothalamus. Indeed, while each of our tissues and organs has its own clock (called peripheral), the brain's master clock is there to synchronize them all and ensure that everyone works in harmony at the right time of day.

But twice a year, this rhythm is disrupted by the time change, which desynchronizes the master clock and all the peripheral clocks…

Since our rhythm is not precisely 24 hours, it resets daily using rhythmic cues from the environment. The most reliable and constant indicator is light. Light naturally controls circadian rhythms, and each morning our master clock is set to the outside world thanks to it.

The master clock then tells time to peripheral clocks in organs and tissues through hormone secretion and nerve cell activity. When we artificially and abruptly change our daily rhythms, the master clock moves faster than the peripheral clocks and that is why we find ourselves disturbed. Our peripheral clocks are still in the previous time zone and we experience jet lag.

It may take several days or weeks for our body to adapt to the time change and for our tissues and organs to function in harmony again. And, depending on whether you're a natural morning person or night owl, the time change in spring and fall may affect you differently.

Night owls will tend to have a harder time adjusting to the spring time change, while morning larks are more affected by the fall time change. Some people are even completely unable to adapt to the time change.

How to best prepare for it

While any disruption to our circadian rhythm can be detrimental to our well-being, there are nevertheless ways to help our body better adapt to the new time:

1. Maintain a regular sleep schedule before and after the time change. It is especially important that the time you wake up in the morning is consistent. In fact, the body releases cortisol in the morning to make you more alert. During the day, you will become more and more tired as cortisol levels decrease, which will limit the impact on your sleep of the time change.
2. Gradually get your body used to the new time by slowly changing your sleep schedule over a week or so. By changing your bedtime 10-15 minutes earlier or later each day, you help your body gently adapt to the new schedule and alleviate jet lag.
3. Enjoy the sunlight in the morning. Morning light helps your body adapt more quickly and synchronizes your body clock – while evening light sets your clock back. Morning light also increases your mood and alertness during the day and helps you sleep better at night.
4. Avoid bright light in the evening. This includes blue light from cell phones, tablets and other electronic devices. Blue light can delay the release of the sleep hormone melatonin and shift our internal clock to an even later time. A dark environment is best at bedtime.
5. Maintain a regular eating schedule. Other environmental cues, like food, can also help synchronize your body clock. Research has shown that exposure to light and eating at the right time can help core and peripheral clocks move at the same speed. Respect meal times and avoid late meals.

The end of the time change?

Following an EU-wide consultation, the European Parliament voted in March 2019 to scrap DST – so this could be one of the last times we'll have to worry to re-set our internal clocks after a time change…

While member states will each decide whether to definitively adopt “standard” time (from fall to spring) or summer time (from spring to fall), scientists are in favor of maintaining winter time, more in tune with natural cycles and when sunlight is most consistent with our social lives: when we go to work, to school and to meeting places.