Shedding Light on the Effects of Daylight Saving Time

By admin
March 10, 2015

Time Change

Daylight Saving Time. It’s designed to give us an extra hour of daylight in the evening and more time to enjoy outdoor activities in the spring, summer and fall. The trade off is that we lose an hour of sleep in the spring and gain an hour back in the fall. So what’s the big deal? While experts disagree on the long-term impact, some studies, including one from the University of Alabama Birmingham, indicate even just a 60-minute change to the inner clock, can throw your body for a loop – changes that range in seriousness from grogginess and lack of focus, to a higher risk of being in a traffic accident or having a heart attack.

DST FACT: Daylight Saving Time in the U.S. begins Sunday, March 8, 2015, 2:00 am, and ends Sunday, November 1, 2015, 2:00 am.

So how does daylight saving time affect your health?

An increase in heart attack risk. We still don’t know exactly why but one serious effect is a 10% increase in the risk of having a heart attack the Monday and Tuesday after moving clocks ahead by one hour in March. The Sunday morning immediately after the time change doesn’t require as abrupt a change, since many people don’t have to go to work. But, the risk appears to peak on Monday morning when the majority of people have to be up earlier to get to work on time. The opposite is true when we turn the clocks back in the fall and get an extra hour of sleep.

Sleep deprivation. Even the change of one hour in your sleep pattern can trigger risks associated with sleep deprivation. We know that sleep-deprivation can result in an increase in blood pressure and the risk of developing diabetes or heart disease. It can also alter body processes including inflammatory response, which can contribute to a heart attack. When you’re sleep-deprived, your sympathetic nervous system goes into overdrive, which puts more stress on your body.

DST FACT: Benjamin Franklin suggested the idea of DST back in 1784, as a way to economize on sunlight and burn fewer candles during winter mornings and nights.

Overeating and weight gain. Skimping on sleep can create a hormonal imbalance within your body, particularly by upping the production of ghrelin – a hormone that regulates hunger. Higher levels of ghrelin may cause you to give in to your cravings and eat more than you should.

Interruption of the circadian clock. Every cell in the body has its own clock that allows it to anticipate when something is going to happen and prepare for it. When there is a shift in one’s environment, such as springing forward, it takes a while for the cells to readjust. The internal clocks in each cell can prepare it for stress or a stimulus. When time moves forward, cell clocks are anticipating another hour to sleep that they won’t get, and the negative impact of the stress worsens; it has a much more detrimental effect on the body.

Changes to the immune function. Immune cells have a clock, and the immune response depends greatly on the time of day. In animal studies, when a mouse is given a sub-lethal dose of LPS, an endotoxin that elicits strong immune responses in animals, the mouse’s survival depends upon the time of day they were given this endotoxin. Mice that were put through a phased advance much like daylight savings time, and then had a challenge to their immune system, died, whereas the control animals that were not subjected to a phased advance, survive when given the same dose of LPS, showing how an acute time change can be detrimental to the immune system response.

DST FACT: The human body’s circadian rhythm – or internal clock – follows the sun and changes depending on where you live. It actually changes in four-minute intervals, exactly the time it takes for the sun to cross one line of longitude.

What can you do to offset the detrimental effects of springing forward into daylight saving time?

Get enough rest the week leading up to the time change so your body is better prepared for the disruption to your inner clock. People who are already sleep-deprived will feel even worse after daylight saving time than those who go into it well rested. Over the daylight saving time weekend, try waking up 30 minutes earlier on Saturday and Sunday than you need to in preparation for the early start on Monday. Eat a balanced breakfast. Don’t rely on extra caffeine to make up for lost sleep time. Go outside in the sunlight in the early morning to allow your inner clock to adjust to the change in sunlight.

The jury is still out on whether the benefits of daylight saving time warrant the disruption to the human body. Experts widely disagree on the severity and the duration of changes to the body brought on by the artificial adjustment to our daily schedules. As with many of the mysteries of the human body, more research is needed to shed a greater light on the short- and long-term effects of DLS. So at least for now, don’t forget to set your clocks forward one hour on March 8, and then relax and try to enjoy your extra time in the sun.

Source: University of Alabama at Birmingham; Women’s Health Magazine; Healthday;

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