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How does daylight saving affect our health

- and what can we do when we cannot sleep?

How does daylight saving affect our healthSleep disorders are common in the western world, and many people find that the problem gets worse when we shift to daylight saving and get an extra hour of light in the evening. It can be difficult to fall asleep when it is still light outside, and this may even be a stress factor for those people who need to get up early the following day. Getting just one hour less of sleep can affect your concentration, mood, heart function, fertility, and a number of other things. Nevertheless, the sleep hormone, melatonin, combined with some practical advice may work wonders for your sleep, and proper sleep is of great importance to your health.

Daylight saving was originally introduced in order to make better use of the light summer nights and to be able to enjoy outdoor activities after work. Daylight saving was also intended to help save energy. Still, there are many arguments that speak against the concept. More animals are killed on the roads (because the sudden shift in car traffic confuses them). There is also an increased number of car accidents and work-related accidents during the transitional period where we have to adjust to the altered 24-hour rhythm. Lack of sleep and lack of the hormone melatonin may also affect our health negatively in several ways.

The long light evenings delay our melatonin production

Melatonin is a hormone that controls our 24-hour rhythm (circadian rhythm) and many other processes in the body. The hormone is produced by the pineal gland, which is localized in the center of the brain. From here, there is a direct nerve connection with the retina of the eye. When we expose ourselves to daylight, the body produces a precursor of melatonin called serotonin. Once it gets dark outside, we start producing melatonin, which makes us feel drowsy and helps us sleep at night.

Our natural melatonin production, in other words, depends on the large contrast between daylight and darkness, also referred to as the astronomical day. The problem is that the long light summer nights delay our natural melatonin production. This creates a problem for the many people who need to be in bed by 9 or 10 pm and need at least eight hours of sleep before getting up at 5 or 6 am.

Melatonin and sleep have many essential functions

Melatonin is of vital importance to our ability to sleep well. It is during this period that we digest our food and recharge – physically and mentally. During the period of deep sleep, toxic waste is removed from the brain. REM sleep (Rapid Eye Movement), which can be compared to a mental laundry, bolsters our learning ability, memory, creativity, and positive mood. Melatonin is even a powerful antioxidant that helps repair cellular damage while we sleep.

How fast do we adjust to daylight saving?

Although many people feel that they adjust to daylight saving in a matter of days, this is not necessarily the case. A 2007 study found that the many peoples’ sleep pattern was still off balance after eight weeks. The majority of people are most sensitive during the first period after setting the clock one hour forward. Lack of sleep may affect quality of life and cause individual health problems as described below.

The most common reactions to too little sleep

In the short run, sleep disturbances typically cause fatigue, poor performance, bad moods, flu-like symptoms, impaired resistance, bad digestion, and blood sugar problems that increase your need for sweets and stimulants.

Heart failure

A study published in the journal Open Heart documents a 25% increased rate of heart failure on the first Monday after shifting to daylight saving compared with all the other Mondays throughout the year. However, the number of heart attacks registered during the first week of daylight saving was no different from the number of heart attacks registered in all the remaining weeks. The researchers believe that the increased number of heart attacks on the first Monday following daylight saving can be explained by a combination of factors involving preexisting heart weakness, sleep disturbances, and stress.
In Finland, it has been observed that the rate of stroke is eight percent higher during the first days of shifting to daylight saving.

More abortions

A study that is published in Chronobiology International shows that women are at increased risk of having a miscarriage during the first weeks after shifting to daylight saving.

Teenagers are very sensitive

Many teenagers and younger people are permanently bothered by disturbed day-and-night rhythm and have problems with falling asleep before midnight. It is also difficult for them to wake up in the morning. This condition is known as delayed sleep phase disorder, and the disturbed 24-hour rhythm occurs because their circadian rhythm (internal clock) is longer than 24 hours.
In a 2015 study published in the Journal of Clinical Sleep Medicine, scientists found that teenagers and younger people are highly sensitive during the first days of daylight saving because they do not sleep as well and have difficulty with concentrating. Several other studies have shown that they are more likely to be involved in traffic accidents.

Depression on the rise during autumn

When the clock is set back one hour in the autumn, the days quickly become shorter. A study from 2016 that is published in Epidemiology shows that the number of people diagnosed with depression increases in the months after resetting the clocks. This is linked to a lack of daylight. Not only is daylight necessary for our daytime serotonin production, it is also needed for our melatonin production at night. Special lamps that can compensate for the lack of daylight help some people.

Lack of sleep is very unhealthy in the long run

People generally sleep less today than they used to. In fact, many of us sleep too little and that poses a serious threat to our health. Chronic lack of sleep speeds up the ageing of the body and increases the risk of many disorders like type-2 diabetes, overweight, irritable bowel syndrome, neurological disorders, atherosclerosis, blood clots, and cancer.

Useful tips for getting enough sleep in the summertime

  • Get plenty of daylight and exercise
  • Avoid caffeinated beverages such as coffee, black tea, and Coca Cola after 4 PM
  • Unwind and relax an hour before going to bed
  • Limit or avoid altogether exposure to LED light from energy saving bulbs, smartphones, and other screens that omit blue light. Use yellow glasses that block out the blue light and prevent interference with the body’s melatonin production
  • Sleep in complete darkness (you may find it useful to use a sleep mask or blackout curtains)
  • Use ear plugs if there is disturbing noise
  • Take a melatonin supplement one hour before going to sleep

Melatonin is nature’s sleeping pill

A melatonin supplement is a natural shortcut to natural sleep because it compensates for the body’s lacking ability to produce the hormone, regardless if it is because of daylight saving, heavy light exposure (at night), shiftwork, or jet-lag. All of these things interfere with the pineal gland’s ability to synthesize melatonin.
By taking a melatonin supplement you trick the body into believing that it is night, even when this is not the case. That way, a melatonin supplement helps induce natural sleep, which is vital for our health and mood.


Pierpaoli Walter, Regelson William. The Melatonin Miracle. Simon and Schuster 1996

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