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 they’re 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 you’ve 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, we’ve 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. A mesh called a stent is placed to help keep
that artery open. The stent also releases medicine that helps
prevent scar tissue from forming at the site. This process is called percutaneous coronary
intervention, PCI and it’s part of something called reperfusion therapy, meaning it helps
get blood flowing in to the heart again. So, cases like KC’s bring up a lot of issues. Data does show an increase in heart attacks
in the few days right after the 1 hour forward. A Letter to the Editor in the New England
Journal Of Medicine in 2008 wrote that in Sweden, from 1987 to 2006, the incidence of
all heart attacks increased in Spring Daylight Saving Time, mainly in the first 3 days after
the time change, and continuing for the week. Interestingly enough, during the Autumn Time
Change, where we go back an hour, incidence of heart attack decreased in the days afterwards. OK, that’s Sweden. Their Daylight Saving time is later in March
compared to the United States. They’re in a different part of the world,
on a different latitude. How about data in America? Well, the published data is more limited. It’s mostly focused on Michigan, they do show that there is an increase in
heart attacks in the immediate days following DST. So the evidence that it happens, is there. The scientific rationale that it happens,
is there. Going an hour forward just before the spring
disturbs sleep quantity and sleep quality in humans. Altering this circadian rhythm, leads to increased
activity of the sympathetic nervous system, which directly affects the heart. Metabolic derangements that mimic type 2 diabetes
happen during this change, along with increased inflammation. For people at risk of developing heart attacks
in the first place, all of these disruptions can be that straw that breaks the camel’s
back, and be that final blockage in the coronary artery, causing a heart attack. KC was allowed to rest after his PCI. Days later, he was discharged. Having an ST elevation Myocardial infarction
puts his 30 day risk of dying between 2-3%. His chances of presenting to the emergency
room again in the next 30 days is max 25%. But not missing his doses of his medicine,
and trying to control his diabetes helped him be in that 97% that don’t die after
a successfully treated heart attack. And it helped him be in that 75% of patients
who aren’t rehospitalized. So the point of this video is to tell you
how a specific type of heart attack happens. If you’re young, and healthy, you probably
don’t have a coronary plaque. It’s not just getting enough sleep, it’s
also getting the right kind of sleep. Slow wave sleep happens hours after sunset,
between around 10pm and 1am. You might miss out on this part if you sleep
late, and miss out on the growth hormone that’s usually released during this time, as dictated
by the circadian clock. Over years, if you don’t sleep well, and
don’t eat well, and don’t exercise, and you smoke, these will add up. Human hearts deteriorate over time no matter
what, but it’s in your control as to how quick that decline happens, based on your
habits and behaviors. But no matter what, that one hour forward
is throwing off hundreds of millions of people, with what looks like minimal benefit, with
harm for patients like KC. Every year there’s a lot more entering that
age 65 and up demographic because of the baby boom generation. Those are the ones who are gonna get hit the
hardest by this. I would prefer we stay on standard time all
year, from a health standpoint. With care from the medical team, diligence
in keeping up with his medicines and staying on top of his diabetes control, KC was able
to make a recovery. And thanks to my good friend, Cardiologist and YouTuber, Dr. Rohin Francis for reviewing this video. Thanks so much for watching. Take care of yourself. And Be Well.
