Time from the beginning of creation, has always played an important role in the functions and activities of man. This has led to the reason why all human beings have an involuntary response to the forces and gravitational pull created by the movements of the earth. This in turn makes man respond to the resulting light-darkness , [ day-night] phenomenon. This brings about the activity of the BIOLOGICAL CLOCK.
The biological clock is a part of our body, which generates a number of biological responses regulated by cycles. Its control center is located in the hypothalamus, a gland located in the brain. Also referred to as the circadian clock when talking about cyclic phenomena which are governed by the clock over a period of 24 hours. Biological clocks produce circadian rhythms and regulate their timing.
In particular
• it regulates body temperature,
• and the cycle of sleeping and wakefulness with waking occurring in the morning and the need for sleep at night.
• There is also a circadian rhythm in certain hormones such as cortisol.
• When traveling with a time zone difference, the biological clock takes several days to readjust to changing light and schedules.
Biological clocks are an organism’s innate timing device.
It is also an innate mechanism that controls the physiological activities of an organism which change on a daily, seasonal, yearly, or other regular cycle.
A few hours ago, three American men , Jeffrey C Hall, Michael Rosbash and Michael W Young,, who worked to explain in detail the importance of the biological clock in man, and how they are linked to other molecular mechanisms and physiological functions , were awarded the Nobel prize for science. They found out discoveries on the molecular mechanisms controlling circadian rhythms – in other words, the 24-hour body clock.
The team were able to say “how plants, animals and humans adapt their biological rhythm so that it is synchronised with the Earth’s revolutions.â€
The team identified a gene within fruit flies that controls the creatures’ daily rhythm, known as the “period†gene. This gene encodes a protein within the cell during the night which then degrades during the day. When there is a mismatch between this internal “clock†and the external surroundings, it can affect the organism’s wellbeing – for example, in humans, when we experience jet lag.
Hall and Rosbash then went on to unpick how the body clock actually works, revealing that the levels of protein encoded by the period gene rise and fall throughout the day in a negative feedback loop. Young, meanwhile, discovered a second gene involved in the system, dubbed “timelessâ€, that was critical to this process. Only when the proteins produced from the period gene combined with those from the timeless gene could they enter the cell’s nucleus and halt further activity of the period gene. Young also discovered the gene that controlled the frequency of this cycle. The team’s discoveries also helped to explain the mechanism by which light can synchronise the clock.
“Every living organism on this planet responds to the sun,†he said. “All plant and animal behaviour is determined by the light-dark cycle. We on this planet are slaves to the sun. The circadian clock is embedded in our mechanisms of working, our metabolism, it’s embedded everywhere, it’s a real core feature for understanding life. “We are increasingly becoming aware that there are implications for human disease,†Nurse added. “There is some evidence that treatment of disease can be influenced by circadian rhythms too. People have reported that when you have surgery or when you have a drug can actually influence things. It’s still not clear, but there will almost certainly be some implications for the treatment of disease too.â€[ courtesy The Guardian London].
Our biological clock helps to regulate sleep patterns, feeding behavior, hormone release and blood pressure.
Importance of Biological clock
We all feel the ebb and flow of daily life, the daily rhythms that shape our days. The most basic daily rhythm we live by is the sleep-wake cycle, which (for most) is related to the cycle of the sun. It makes us feel sleepy as the evening hours wear on, and wakeful as the day begins. Sleep-wake and other daily patterns are part of our circadian rhythms, (circum means “around†and dies, “dayâ€) which are governed by the body’s internal or biological clock, housed deep within the brain.
Circadian rhythms can influence sleep-wake cycles, hormone release, eating habits and digestion, body temperature, and other important bodily functions. Biological clocks that run fast or slow can result in disrupted or abnormal circadian rhythms. Irregular rhythms have been linked to various chronic health conditions, such as sleep disorders, obesity, diabetes, depression, bipolar disorder, and seasonal affective disorder.
But research has been finding that the body’s clock is responsible for more than
• just sleep and wakefulness. Other systems,
• like hunger,
• mental alertness,
• and mood,
• stress,
• heart function, and
• immunity also operate on a daily rhythm.
Disrupting our body’s natural cycles can cause problems. Studies have found there are more frequent traffic accidents and workplace injuries when we spring forward and lose an hour of sleep. Heart patients are at greater risk for myocardial infarction in the week following the Daylight Savings time shift. But even more significant is that science continues to discover important connections between a disrupted clock and chronic health issues, from diabetes to heart disease to cognitive decline.
It turns out that the same genes and biological factors that govern our internal clock are also involved in how other body systems operate — and break down. It can be hard to determine whether a disrupted clock leads to health problems, or whether it’s the other way around.
We’re beginning to understand more about how the clock interacts with and helps govern the function of other systems and affects our overall health. In fact, keeping your body’s daily cycle on an even keel may be one of the best things you can do for your overall health.
Natural factors within the body produce circadian rhythms. However, signals from the environment also affect them. The main cue influencing circadian rhythms is daylight. This light can turn on or turn off genes that control the molecular structure of biological clocks. Changing the light-dark cycles can speed up, slow down, or reset biological clocks as well as circadian rhythms.
1. Environmental disruptions to the body’s clock
Some of the best knowledge we have about the roles the biological clock plays in our health come from instances in which the cycle gets out of sync. This can happen for different reasons, and we’re just starting to understand them in greater detail. Sometimes we do things ourselves that disrupt our normal rhythms, like flying to a distant time zone. Sometimes it’s other factors, (like genes or biology) that play a role.
• Jet Lag
Flying across the country on the red-eye is a prime example of how we can disrupt our own clocks, and a far more extreme example than the spring forward/fall back ritual in many parts of the U.S. When jet lag sets in, we feel disoriented, foggy, and sleepy at the wrong times of day because, after changing time zones, our body clock tells us it’s one time and the outside environment tells us it’s another. In fact, jet lag can be considered one type of circadian rhythm disorder. It can be treated simply be allowing the body to adjust to the new time, although it may take several days for external cues (light) to help the internal clock catch up or fall back with its new cycle.
• Shift Work
Shift work is another example of how we can get ourselves off-cycle, and this too can develop into a circadian rhythm disorder over the long term. People who work the night shift not only have a hard time with their sleep patterns (feeling sleepy at work or experiencing insomnia during the day), but other systems in their bodies can also feel the effects — and they can be chronic. It’s not been clear exactly why this connection exists, but weight gain or metabolic changes may be involved. These phenomena underline how particular behaviors or lifestyles can affect the body’s clock, but there are other factors at play, like genetics and body chemistry.
2. Rhythm and Moods
Our internal clocks also have a hand in whether we feel up or down emotionally. People with mood disorders like depression, bipolar disorder, and seasonal affective disorder (SAD) have altered circadian rhythms. In fact, sleep disturbances, both sleeping too much and too little, are one of the key symptoms of depression and other mood disorders.
The relationship between body rhythms and mood is an intricate one, and likely has to do with how the brain chemical serotonin fluctuates in relation to the light-dark cycle and throughout the year as the days become longer and shorter. Mice bred to have problems with serotonin function also have seriously altered daily rhythms. People’s serotonin levels increase during the part of the day when there is more light available.
Understanding what makes biological clocks tick may lead to treatments for sleep disorders, obesity, mental health disorders, jet lag, and other health problems. It can also improve ways for individuals to adjust to nighttime shift work. Learning more about the genes responsible for circadian rhythms will also help us understand biological systems and the human body.
Fertility
The timing of life , as influenced by the biological clock, affects the ability of both men and women to reproduce.
Research has shown that age affects a man’s ability to have a child in a similar way to a woman.
Women
As a woman goes from her 20s to her 30s to her 40s without having children, she’s likely to hear more and more people warn her about the risks in waiting to get pregnant.
You might assume that biology explains why women face so much pressure to have kids as they age, but men don’t. After 35, the thinking goes, it gets harder for a woman to get pregnant, and, if she does conceive, there’s a greater risk the baby will have health problems. According to that thinking, men are mostly untouched by this process, often able to father kids until a ripe old age. Except it turns out this isn’t really true.
Men
Researchers are increasingly arguing that men have a biological clock, too, even if most people don’t hear it ticking.
It is known that age affects a man’s ability to have a child in a similar way to a woman’s, though the timeline isn’t the same. It’s harder for older men to father children, and their offspring are more likely to have health problems, too. In fact, new research suggests that many problematic genetic conditions may be more closely linked to the age of the father than the mother.
But few people today seem to be aware of how a man’s age can affect a pregnancy and the health of the child. The missing knowledge could be useful for a young couple thinking about when to have kids, or a childless older couple feeling the pressure of aging. It could be a strong reason for many couples to rethink their plans about career and family, and for many people to reexamine their ideas about work, gender and their health.
Studies indicate that a man’s age can affect his fertility in three main ways. The older the father, the harder it may be for a couple to conceive a baby. Older fathers are also more likely to see pregnancies result in miscarriages. And the older age of the father can potentially trigger health problems in a child, too.
Unlike women, who are born with a finite number of eggs, men continue to produce sperm throughout their life, and some can father children into their 60s and beyond – an age where women’s clocks have totally stopped ticking. George Lucas, Steve Martin and Rod Stewart all famously fathered children in their late 60’s. But for most men, testosterone declines as they age, which can lead to decreased libido and erectile dysfunction. And as they get older, men also see a decline in the quantity and genetic quality of sperm.
The aging male, at least from a reproductive perspective, is not as good when he’s older as when he’s younger.
These changes mirror similar changes in women, with a notable difference: Most seem to occur a few years later in men, and happen more gradually.
There’s a lot of disagreement about when exactly in a man’s and a woman’s life these changes occur; various studies and experts cite different ages and time periods. But many argue that, for women, fertility declines gradually in the mid- to late 30’s, and then sharply in the 40’s. For men, the change appears to happen more in their 40’s and 50’s.
One study of 2000 couples in France found that while women’s reproductive capacity tends to decline around 35, men experience a similar, though more gradual, decline after the age of 40. Several studies suggest that men over the age of 35 are twice as likely to be infertile as those younger than 25. Another study of about 2,000 couples in the U.K. showed that, after controlling for a woman’s age and other factors, men who were 45 and older took five times longer to conceive than those who were 25 and younger.
