What makes your biological clock tick? We all have tiny timepieces inside us that keep us on our 24-hour cycles, the time it takes the earth to spin around its axis. Your body clock resets itself daily. Your cells can actually tell the time and use it to control your behavior. But how does your clock work at the molecular level?

This timekeeping is a core property of life around your revolving planet. Your survival and your functioning are vitally dependent on it. Day and night, your pacemakers keep running. Your inner clock tells you to wake up and when to sleep.

When your clock loses it’s timing due to lack of sleep, your body temperature, appetite, blood pressure, hormone secretion, urine production, changes in blood, and sleep timing are all affected. These changes can shift or disrupt your cycle.


The clock genes in your cell’s DNA control these timing mechanisms. The first clock gene was discovered in 1971, followed by dozens of clock timing genes. They make long stings of protein molecules that control your bodily functions.

These genes and proteins fit together like the gears in a clock turning the crank out into a 24-hour circuit. You can reset the timing to make up for daylight saving time, night work, and jet lag.


Disturbed rhythms have adverse health consequences on peripheral organs outside the brain, particularly in the development or exacerbation of cardiovascular disease, bipolar disorders, decreased melatonin production, and jet lag.


You can advance your sleep phase by one hour each day. After starting a new routine, which requires you to get up earlier than usual, you start to fall asleep at night earlier

Without clocks or time clues, you tend to go to bed an hour later and to get up about an hour later each day. Experiments demonstrate that the "free-running" circadian rhythm in humans is about 25 hours long.

To maintain our 24-hour day/night cycle, the biological clock needs regular environmental time cues called Zeitgebers, e.g. sunrise, sunset, an alarm clock, meal times, and change in your daily routine. Time cues keep your normal human circadian clock aligned with the rest of the world.


Since organisms like cyanobacteria, without brains have circadian rhythms, how can your rhythms need and be controlled by your brain? Plants also have a circadian clock, which controls photosynthesis and flowering.


Research shows when you get only 6 hours of sleep compared to your usual 8 hours, your cortisol levels drop 50%. A midday snooze the next day restores those cortisol levels.


Light is the number one influence and most powerful internal clock the quantity and quality of light plays a significant role in mood and work performance.

Spending a lot of time in front of your computer and/or under indoor lighting conditions where the light is fluorescent (green) or incandescent (orange), results in physical, mental, and emotional disturbances.

You can prevent these problems by buying a full spectrum light bulb and put it in your desktop task light. It is a good idea to use a full spectrum light for everywhere you read, write, do computer key entry or do close work of any kind. Although full spectrum bulbs cost more for each bulb, they use less energy and last five to seven times longer than regular light bulbs.


Every workday is divided into cycles that match your naturally heightened abilities, both physically and mentally. The trick is to take advantage of identifying and using this information to schedule your work and non work activities.

The adrenal glands in coordination with your pituitary, hypothalamus, pineal glands control both your internal clock and your stress levels. Your natural rhythms shorten as you age. Staying healthy keeps your innate circadian cycle all through your life.

To work and live at your best, you need your internal circadian rhythm in harmony or synchronized with the your environmental cues (i.e., light and dark, temperature etc).


Several nights of sleep deprivation leads to dull sensory perceptions (vision, hearing etc.), longer reaction time, slower motor coordination, reduced memory retrieval, lowered new memorization ability, as well as increased irritability.


When the sleeping temperature is above 75 degrees, your sleep and Rapid Eye Movement (REM) or dream cycles are disturbed and you tend to wake up more often.

When the sleeping temperature is below 65 degrees, your dreams become unpleasant and contain emotional conflicts.


Working in a cold room increases your chances of a repetitive stress injury. Your mental abilities and physical functions coordinate with your body temperature. Your body temperature warms up in the morning and cools down at night. No matter what time it is, the colder you are the slower your senses will function.

Your ability to multiply quickly and accurately varies directly with body temperature also. Around 4 AM you settle into your lowest body temperature. The pituitary and adrenal glands start sending out wake up hormones.

Your temperature begins to gradually rise until around 5 AM - 7 AM. This also gives your body the opportunity to discharge the chemicals that keep you paralyzed during your dream state (so you don't hurt yourself).

Then, you can get up and move about trying not to lose your balance. A quick warm shower wakes you up by raising your body temperature. Both men and women's hormones flow more quickly as body temperature rises and then peaks out around mid-morning.


Regular exercise increases everyone's cognition capability and releases stress from our bodies. For most men, the best time to exercise is in the afternoon. Women who exercise in the morning raise their serotonin levels. This prompts a positive mental state.

Exercising in the evening disturbs the natural slowing down cycle leading to sleep. So a good thing like exercise can be even better if you know your best timing.


Japanese people who are most Americanized have five times the heart disease compared to those who continue to practice their more traditional cultural habits and diets.

The heavier the meal (high fat, more than 4 ounces of meat, etc.) the more physical lethargy you will have and the deeper your loss of mental focus. Heavy meals make the stomach use more oxygen that would otherwise be available for your brain functions.


Studies have indicated that among people living under the airport approach route there is a thirty percent higher rate of admissions to mental hospitals.


Stress causes your internal rhythms to lose synchronicity. It subverts your natural circadian rhythms that affect your sleep, eating and all body functions. Stress breaks down the immune system and leads to weakness, illnesses, and injuries.

Physical factors like temperature, sound, vibration, movement and humidity all disturb your clock rhythms.

Physiological stressors as sleep disturbance, irregular eating, alcohol and nicotine (depressants) and caffeine (stimulant) also change your rhythms.

Psychological stressors as fear, frustration, social problems, and work pressures all play roles in disturbing your natural clock rhythms.


Your body operates in ninety minutes activity cycle. Under stress, the cycle shortens to a one-hour cycle (the same as in infancy). The natural activity cycle you are programmed for is made up of 30 minutes rest followed by 60 minutes activity followed by thirty minutes rest. Now being at rest doesn't mean sleeping! It means alternating the kinds of activities you do every day for a little physical and mental variety.

You will think faster, produce more offspring, enjoy better health, do better work, and live longer when your time settings and environment cycles match.

Listen to your body clock and stay healthy.

Nimmo, Univ. Glasgow, Scotland/ Dunlap, Dartmouth CollegeArnold, Univ. Georgia, Journal National Academy of Sciences Jan 2009