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Don’t let daylight savings get you down (11/21/10)

November 21, 2010

Messing with Mother Nature

It happens like clockwork every year.  Patients arrive  and tell me they can’t handle daylight savings.  The body clock change of merely one hour, compared with a flight to Europe, where the change is usually six hours, makes them feel uneasy, skittish, unhappy, unmotivated, and fatigued.

How come?

Here are some of the answers:

1. Time rules life.  All your physiologic functions are controlled by body clocks that literally time every cell in your body. If the timing is off, you’re off.

2. Humans did not evolve with jet lag or daylight savings.  We probably evolved to go to bed after dark and get up with dawn.  In experiments done at NIMH in the 1990’s where people lived that way, they generally felt that had better mood and a completely new appreciation of what it means to be alert.

It does make sense – our bodies are built to change with the night and day changes of the earth – one reason we have such powerful inner clocks (see my “Body Clock Advantage” for more on this.)

3. Inner body clocks also greatly influence  all human performance and mood.

4. Light sets inner body clocks. Light, including artificial light is also an effective drug for depression – especially seasonal depression, but even for the garden variety type that affects a large minority of the population.

5. As Siegfried Kasper showed when at NIMH over twenty years ago (he’s now head of psychiatry at the University of Vienna,) about 25-50% of northeastern Americans get marked depressive mood swings in the wintertime, though only about 2-4% get major seasonal depression, leaving them mainly unable to properly function. Those living in the southern US often have similar problems in the summer, especially if they stay inside due to hot, humid weather.

All in all, there are good biological reasons for you to have trouble with daylight savings.


The solutions lie with what causes the problem in the first place.   Light sets your biological clocks.

For most of us that means sunlight.  So the first order of business when daylight savings disrupts your mood and life is to get sunlight.

Timing matters, however.  You want to know if your day length is getting longer or shorter.

The reason is light at different times has opposite results.  Morning light makes your “inner day” shorter; evening, or especially bright night light, makes your inner day longer.

So on the days when daylight savings makes you “lose” an hour, you want to get lots of morning light.  On days when you “gain” an hour, you want to get plenty of evening light.  If that’s not available, a light box of the sort sold to treat seasonal depression should work.

The Added Usefulness of Exercise

Work done over many years by Leon Lack in Australia shows that the body clock effects of light can be increased through exercise.  So one antidote to daylight savings goes like this:

When the day is suddenly made shorter, walk in sunlight in the morning.  Try not to get too much evening light for a while.

When the day is suddenly one hour longer, walk in sunlight in the evening.  Wear sunglasses if you can during the morning.

And for all of the population, get sunlight – on your eyes (don’t look at the sun – reflected light is fine, as is light through a window.) Light on the skin does not change your biological clocks.  It may provide useful vitamin D, but it also provokes skin cancer, especially when obtained in the middle of the day. Wearing a hat is another good idea for preventing skin cancer, which tends to afflict our faces more than anywhere else.

Times does rule life. Light sets your inner time.  Light is a drug in many, many ways – a topic for another time.
Rest, sleep, Sarasota Sleep Doctor, well-being, regeneration, longevity, body clocks, insomnia, sleep disorders, the rest doctor, matthew edlund, the power of rest, the body clock, psychology today, huffington post, redbook, longboat key news

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