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  • KC is a 79 year old man, presenting to the emergency room with chest pain radiating to

  • his left jaw.

  • His wife Jane, tells the admitting nurse that earlier in the morning, he had become short

  • of breath.

  • He felt nauseous, and light headed, before collapsing to the floor.

  • You see, KC was observing a yearly time change enacted by US Law, Daylight Saving Time, where

  • everyone in the country would set their clock forward 1 hour at 2am the second Sunday in

  • March.

  • Officially, the reason to do this is to save energy and boost the economy by increasing

  • the number of daylight hours during spring and summer seasons, but KC’s case is part

  • of a building body of evidence: this time change can negatively affect human health.

  • Immediately after setting his clock an hour forward, KC felt disoriented.

  • He had done this before for the last 45 years of his life, so there’s nothing different

  • on this Sunday in March.

  • He did have trouble sleeping that weekend because of the time change, though he didn’t

  • think too much of it.

  • But the next day on Monday morning, just before breakfast, KC suddenly felt his jaw become

  • stiff.

  • His chest instantly tightened up.

  • He gripped the armrests of his chair, because every breath he tried to take, was a struggle.

  • He didn’t want to tell his son downstairs, because he thought it would frighten the grandkids.

  • He didn’t want to tell his wife, because he thought she’d overreact.

  • He didn’t think this was a big deal.

  • At lunchtime, KC tried to lay down because he thought he could sleep this off.

  • But 20 minutes later, he vomited 3 times with no relief.

  • KC couldn’t take it anymore.

  • He could barely breathe anymore.

  • His wife found him collapsed on the floor as she called for 911, and he’s brought

  • to the emergency room where we are now.

  • Given this history of present illness, there’s a few clues as to what’s happening.

  • Chest pain with shortness of breath could be a problem of the lungs.

  • But it could also be a problem of the heart.

  • KC had a prior history of diabetes and asthma, which could be the main problem here, but

  • there’s more going on.

  • The medical team immediately draws some of KC’s blood, and they hook him up to an ECG.

  • Proteins and enzymes from his heart muscle were found floating around in his blood, and

  • the ECG confirmed the medical team’s suspicions: KC is having an ST-elevation Myocardial Infarction.

  • Myo meaning muscle.

  • Cardia from Ancient Greek referring to the heart.

  • Infarction from Latin farcire meaning to stuff into, and more modernly meaning a blockage

  • of blood flow, causing cell death.

  • Death of heart muscle, due to a blockage of blood flow.

  • And ST-elevation referring to the ECG reading that he has a specific change in the electricity

  • of his heart, meaning he is having a heart attack, which brings us to the next clue.

  • KC told the medical team that he was a type 2 diabetic.

  • This means that his body’s cells are resistant to insulin.

  • This is a hormone your body releases after you eat.

  • Insulin enables the shift of those nutrients you just ate, in to the cells, like sugar.

  • When the body doesn’t respond to insulin anymore, blood sugars stay high, because theyre

  • not going in to the cells, but also, the body starts putting out wrong signals because it

  • thinks that insulin isn’t being released, so it asks for more.

  • The body, thinks it’s starving and starts metabolizing fat stores in to the blood stream.

  • As these fats float around, some of them, get transported in to the liver, to make cholesterol.

  • All of this causing hyperlipidemia.

  • Hyper meaning high.

  • Lipid referring to fats, And emia meaning presence in blood.

  • High fat presence in blood.

  • This means these blood fats will start pooling in the vessels that supply blood to the heart,

  • called the coronary arteries.

  • The heart is a large muscle.

  • Big muscles are very oxygen hungry, so they need a lot of it to function.

  • Blocking the coronary arteries will starve the heart of oxygen, and cause parts of it

  • to die.

  • And in KC, parts of his heart, were starting to die, bringing us back to the name ST-elevation

  • Myocardial Infarction.

  • KC was at increased risk of heart attack to begin with.

  • At 79 years old, his heart has degraded over time because of normal wear and tear.

  • No one at 80, has the same heart as they did when they were 20.

  • But KC’s heart also degraded more because his diabetes means his body’s metabolism

  • can’t get his blood sugars right.

  • His body can’t get his blood fats right.

  • And his body can’t signal right with the correct hormones.

  • Fats start to pool in his coronary arteries.

  • This causes the smooth muscle lining inside the arteries, to die.

  • But it’s not done h ere.

  • White blood cells rush in to the site because they detect damage.

  • They start to engulf the dead cells of the artery wall, but they also engulf the fats.

  • And as more fats keep accumulating, these white blood cells start to die too [necrotic

  • core].

  • Smooth muscle cells start to make collagen and proteins, to cover up this dead necrotic

  • core.

  • This fibrous cap seals the area, and the plaque formation is complete.

  • But while this plaque can cause a heart attack by itself

  • ,it isn’t always an ST-elevation heart attack.

  • ST-elevation means full blockage, meaning whatever is there isn’t just fat, but something

  • else too.

  • But what could it be?

  • Well, it would have to be something that’s already in the blood.

  • It could be more fat, but probably not likely since this is so sudden.

  • It’s not sugar because that’s probably not going to clump up in solution.

  • But speaking of clumping up, how about a blood clot?

  • This additional blockage can happen suddenly.

  • It can block the whole thing.

  • It can cause immediate changes in an ECG reading, that changes over minutes, as heart muscle

  • keeps dying from the lack of oxygen.

  • Without fresh blood flowing in, waste products from cells begin to accumulate.

  • The heart tries to compensate, but as each minute passes by, parts of KC’s heart keep

  • dying.

  • But why would this blood clot form?

  • Clots usually form when you get a cut, like on your skin, so did he get a cut inside a

  • coronary artery?

  • How would that even happen?

  • Well, the plaque is made of cholesterols, and white blood cells that died when they

  • engulfed too much fat.

  • The plaque is inflamed.

  • Inflammation is what happens like when you get a cut.

  • Diabetes put someone in a pro-inflammatory state.

  • The immune system expands the blood vessels so more fluid can flow in, and more immune

  • cells can enter the area.

  • The thing is, the chemicals released by the immune cells during inflammation in and around

  • the plaque, breakdown the fibrous cap.

  • The plaque ruptures.

  • Other blood cells think the vessel wall is injured, like a cut, and start clumping there.

  • This completely blocks artery very quickly, causing KC’s sudden heart attack.

  • So that’s the how of KC’s heart attack.

  • But why did it happen?

  • And what does it have to do with Daylight Saving time?

  • Well, it might have a lot to do with it.

  • This brings us to a concept called the circadian rhythm.

  • This refers to our body’s natural clock.

  • Science suggests that human circadian rhythms are based around sunlight.

  • So this directly ties our internal clocks with sleep.

  • This is why it’s harder to take a nap in the morning if youve been sleeping well

  • the past few nights.

  • It’s why many people feel gross pulling all-nighters and waking up at night time when

  • it’s dark outside.

  • And the sunlight hypothesis is why we think computer screens, which mimic daylight, keeps

  • us up at night and disrupts sleep.

  • There are differences between people in terms of their biological clock.

  • Some are early morning people.

  • Some are night owls, but the overwhelming majority of people show differences in the

  • activity in their bodies at different times of day.

  • In human experiments, weve found that sleep deprivation increases inflammation.

  • The average sleep duration in Western societies decreased from 9.0 to 7.5 hours in the last

  • 100 years, and it looks like it’s decreasing still.

  • In that same experiment, scientists found that depriving someone of sleep, impairs their

  • insulin sensitivity and glucose tolerance.

  • More evidence from decades worth of studies show that night shift workers, that is people

  • who work overnights, do have a higher chance of developing diabetes and cardiovascular

  • disease over years if they keep working those tough shifts, due increased inflammation,

  • decreased insulin sensitivity and impaired glucose tolerance.

  • All three of these, were already a problem in KC because he had diabetes, but there’s

  • more.

  • Daylight saving time has been shown to disrupt human circadian seasonal adjustment.

  • On the second Sunday in March, most of the United States sets their clock forward one

  • hour.

  • This date, sits about a week and a half from the northern hemisphere spring equinox.

  • Right around this time, sunrise and sunset widen dramatically, which means our bodies

  • are already adapting to seasonal change.

  • But when an arbitrary one hour shift happens, it forces yet another change on our bodies.

  • This extra disruption in circadian rhythm significantly changes what genes are expressed

  • in the bodies.

  • It inflicts signal changes disrupting sleep, increasing inflammation, decreasing insulin

  • sensitivity, causing a cascade of metabolic derangements.

  • Some of the data shows that there is an increased incidence of heart attack in the days following

  • the 1 hour forward adjustment, in line with the scientific reason for why it happens.

  • Young people can tolerate these changes, but elderly with preexisting conditions likely

  • cannot handle this, which brings us back to KC.

  • As each minute passes, his chances of dying from his heart attack increase.

  • He’s immediately sent in to the hospital’s Cath lab.

  • This is a place where doctors can use imaging equipment to see the arteries and chambers

  • of his heart.

  • They send a small wire through a blood vessel in his wrist, to reach his heart.

  • They find the blood vessel that’s completely blocked.

  • A balloon is placed on the wire and through the blockage, and it’s inflated, popping

  • the blood vessel open.