Circadian medicine's quest to make the most of our biological clocks
Circadian medicine's quest to make the most of our biological clocks
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"Time", when we think about it, tends to appear to us as extrinsic, a feature of our landscape: we follow our passage through it as if we were crossing an invisible place. geography, our progress charted by wristwatch, clock, calendar. Humans didn't invent time, of course, but you could reasonably argue that because we invented the units we use to track it - hours, minutes, seconds - we have every right to tinker with them when we do. want to. At least, that was the position the Senate took on March 15, when, in a surprise and surprisingly unchallenged vote, it passed the Sun Protection Act. The new law, if the House agrees and the President signs it, would make daylight saving time permanent, effective November 5, 2023.
The change has long been a desire of the retail industry because it believes shoppers spend more money when it stays light later. But lawmakers also appear to have viewed the annual clock rollback as a personal affront: the groggy mornings that result from the 6 a.m. to 5 a.m. shift, the morale killer for Boston and Billings when darkness descends suddenly shortly after 4 o'clock in the afternoon. . When the yeses won, there was bipartisan applause, as if a particularly hostile foreign adversary had been defeated.
What most of these lawmakers didn probably didn't realize is that the enemy wasn't just outside of us - a social agreement on how to label every moment of our existence in relation to the sun - he was also inside. inside us, where our internal organs also keep time. In fact, most of our physiological functions are governed by countless numbers of carefully synchronized biological clocks that each cycle approximately every 24 hours. These cycles are known as circadian rhythms, from the Latin for "about" (circa) and "day" (dies ).
Many of us are familiar with circadian rhythms as a way of referring to our sleep cycle. In 1972, scientists discovered that this cycle is mediated by an area of the brain's hypothalamus called the suprachiasmatic nucleus. This structure coordinates the release of hormones - among them dopamine - which lower body temperature and blood pressure and make us sleepy; in the morning, cortisol and other hormones restore our alertness, warm us up and increase blood pressure. It is believed that the increase in blood pressure in the morning is one of the reasons why heart attacks occur more often than in the afternoon.
Over the past two decades, however, researchers have discovered that the brain's clock is by no means the only one in our body. It turns out that most of our cells contain a group of genes that could be thought of as gears in a mechanical watch, keeping time everywhere internally. These "clock genes" - there are at least six of them that are considered integral to the functioning of the watch - work together in the same way in every cell. And just as they cause the release of hormones in the brain, they dictate other processes in other parts of the body. In the early 2000s, advances in the ability to detect gene activity in various tissues revealed that cellular clocks are organized into distinct organ-level clocks representing each physiological system: there is a skin clock, a hepatic clock and an immune system clock. ; there is a clock for the kidneys, heart, lungs, muscles and reproductive system. Each of these clocks synchronizes with the central clock of the brain like a section of an orchestra following its conductor. But these sections also adjust how and when they operate based on guidance they receive both from the environment and from each other, and their synchronization can provide information to the central clock and cause it to adjust the time that it also keeps. The liver, for example, determines when to rev up your metabolism based on when you eat; if you do this in the middle of the night, the liver will...
To hear more audio stories from publications like the New York Times, download Audm for iPhone or Android.
"Time", when we think about it, tends to appear to us as extrinsic, a feature of our landscape: we follow our passage through it as if we were crossing an invisible place. geography, our progress charted by wristwatch, clock, calendar. Humans didn't invent time, of course, but you could reasonably argue that because we invented the units we use to track it - hours, minutes, seconds - we have every right to tinker with them when we do. want to. At least, that was the position the Senate took on March 15, when, in a surprise and surprisingly unchallenged vote, it passed the Sun Protection Act. The new law, if the House agrees and the President signs it, would make daylight saving time permanent, effective November 5, 2023.
The change has long been a desire of the retail industry because it believes shoppers spend more money when it stays light later. But lawmakers also appear to have viewed the annual clock rollback as a personal affront: the groggy mornings that result from the 6 a.m. to 5 a.m. shift, the morale killer for Boston and Billings when darkness descends suddenly shortly after 4 o'clock in the afternoon. . When the yeses won, there was bipartisan applause, as if a particularly hostile foreign adversary had been defeated.
What most of these lawmakers didn probably didn't realize is that the enemy wasn't just outside of us - a social agreement on how to label every moment of our existence in relation to the sun - he was also inside. inside us, where our internal organs also keep time. In fact, most of our physiological functions are governed by countless numbers of carefully synchronized biological clocks that each cycle approximately every 24 hours. These cycles are known as circadian rhythms, from the Latin for "about" (circa) and "day" (dies ).
Many of us are familiar with circadian rhythms as a way of referring to our sleep cycle. In 1972, scientists discovered that this cycle is mediated by an area of the brain's hypothalamus called the suprachiasmatic nucleus. This structure coordinates the release of hormones - among them dopamine - which lower body temperature and blood pressure and make us sleepy; in the morning, cortisol and other hormones restore our alertness, warm us up and increase blood pressure. It is believed that the increase in blood pressure in the morning is one of the reasons why heart attacks occur more often than in the afternoon.
Over the past two decades, however, researchers have discovered that the brain's clock is by no means the only one in our body. It turns out that most of our cells contain a group of genes that could be thought of as gears in a mechanical watch, keeping time everywhere internally. These "clock genes" - there are at least six of them that are considered integral to the functioning of the watch - work together in the same way in every cell. And just as they cause the release of hormones in the brain, they dictate other processes in other parts of the body. In the early 2000s, advances in the ability to detect gene activity in various tissues revealed that cellular clocks are organized into distinct organ-level clocks representing each physiological system: there is a skin clock, a hepatic clock and an immune system clock. ; there is a clock for the kidneys, heart, lungs, muscles and reproductive system. Each of these clocks synchronizes with the central clock of the brain like a section of an orchestra following its conductor. But these sections also adjust how and when they operate based on guidance they receive both from the environment and from each other, and their synchronization can provide information to the central clock and cause it to adjust the time that it also keeps. The liver, for example, determines when to rev up your metabolism based on when you eat; if you do this in the middle of the night, the liver will...
