That Dreaded Time Change: the science of chronobiology

Chrono means time, so chronobiology is about how time affects our biological systems. We have long known how important time is to our bodies: the term “biological clock” is well established in our language and our culture.

Chinese medicine recognised that the body has an internal clock

about 4,000 years ago: there are 2 hours associated with each organ system. Problems with that organ system will tend to occur in that time window, for example, 1-3 am is liver time, and people whose livers are congested (and could benefit from a detox) often find themselves waking between those hours.

Chinese medicine is also organised around the principle that the seasons are associated with different organs: liver in spring, heart in summer, lungs in fall and winter for kidneys. It’s good to support that organ during its season.

Women’s menstrual cycles often align with full or new moons, which is why they were called moon cycles in some cultures. In the modern world, with light affecting us all hours including times that are naturally dark, many women have lost this connection with the natural cycles.

Many of us dread the time change, feeling less productive and out of sorts for days after. It is not as easy as flipping a switch: there are deeply ingrained “clocks” in every cell of our body, and we are meant to live by the natural rhythms of sunrise and sunset.

Every year in spring, when we’re forced to move the clocks ahead by an hour, parents have a difficult time getting kids to bed, and a hard time getting them up in the morning. There are documented increases in workplace injuries, car accidents, heart attacks and strokes. It’s even been found that judicial sentences tend to be harsher at this time! 

Psychology professor Michael Antle, of the Canadian Centre for Chronobiology, explains that humans live by three clocks. These include the light clock, or solar clock, and the body clock, governed by the circadian system in our brains. Third is the social clock, responding to the demands of work, school, and other social responsibilities and activities. While our circadian clock is meant to follow the solar day, society dictates that we follow the social clock.

The human circadian clock runs a little slower than 24 hours, so we need to nudge it forward and reset our clocks each day. Slow clocks need morning light. With daylight savings time (DST), we get less light in the morning, making it harder to start our days, although our social clock says we must. 

Our biological clocks are genetic, and appear to be fairly hard-wired. Light exposure affects them: we need environmental light signals to entrain these biological rhythms. Research by Nobel Laureate Michael Young has revealed fascinating information about our cellular clocks. His experiments on mice showed that the brain is actually the first system to adapt to changes in light exposure, while other tissues take longer to adapt, with the liver being slowest of all, taking seven days to adapt. 

Interestingly, it has been found that about half of our genes have a circadian pattern in their expression. This is an area of intense study in pharmacology. Of the 100 most-used drugs, 56 of them have targets with circadian rhythms, meaning that effects of the drug may vary depending on what time of day it is taken. This can reduce the effect of the drug by up to 75%, just by taking it at a less optimal time.

Tips To Make The Transition Easier:

1. Go to bed and get up at the same time. If you normally go to bed at ten, resist the urge to go to bed earlier in the first few days of the time change. If you find the transition particularly difficult, you may want to adjust your sleep/wake schedule by 15 minute intervals every few days in the two weeks leading up to the time change.

2. Practice good sleep habits. Avoid coffee for at least 6 hours before bedtime, and avoid alcohol in the evening. Remember, your liver is the slowest organ to adjust! Make sure the last hour before your intended bedtime is screen-free. The blue light emitted by all screens disturbs melatonin production. Low lamp light, or a bath by candlelight is a good way to spend the last hour before bed.

3. Keep dinner time as consistent as possible. Our eating patterns and sleep patterns affect each other, and your organ clocks are still adjusting. Eat lightly at dinner, with an emphasis on protein and vegetables.

4. When you wake on the Sunday after the time change, and for a few days after, get outside as early as possible to bathe yourself in morning light. A walk at sunrise is ideal.

5. If you are really dragging, a short catnap in the afternoon can be helpful. Keep your nap less than 20 minutes, and try not to nap later than 2 pm.