[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:07.60,0:00:10.58,Default,,0000,0000,0000,,It starts with a cough,
Dialogue: 0,0:00:10.58,0:00:12.05,Default,,0000,0000,0000,,or a wheeze.
Dialogue: 0,0:00:12.05,0:00:14.37,Default,,0000,0000,0000,,Soon, your chest feels tight.
Dialogue: 0,0:00:14.37,0:00:17.22,Default,,0000,0000,0000,,Your breathing speeds up\Nand gets shallower,
Dialogue: 0,0:00:17.22,0:00:19.59,Default,,0000,0000,0000,,making you feel short of breath.
Dialogue: 0,0:00:19.59,0:00:23.38,Default,,0000,0000,0000,,These are common symptoms\Nof an asthma attack.
Dialogue: 0,0:00:23.38,0:00:27.75,Default,,0000,0000,0000,,Around the world, more than 300 million\Npeople suffer from asthma,
Dialogue: 0,0:00:27.75,0:00:32.42,Default,,0000,0000,0000,,and around 250,000 people \Ndie from it each year.
Dialogue: 0,0:00:32.42,0:00:37.63,Default,,0000,0000,0000,,But why do people get asthma\Nand how can this disease be deadly?
Dialogue: 0,0:00:37.63,0:00:39.90,Default,,0000,0000,0000,,Asthma affects the respiratory system,
Dialogue: 0,0:00:39.90,0:00:42.38,Default,,0000,0000,0000,,particularly the smaller airways,
Dialogue: 0,0:00:42.38,0:00:45.42,Default,,0000,0000,0000,,such as the bronchi and bronchioles.
Dialogue: 0,0:00:45.42,0:00:48.82,Default,,0000,0000,0000,,These airways have an inner lining\Ncalled the mucosa
Dialogue: 0,0:00:48.82,0:00:52.44,Default,,0000,0000,0000,,that's surrounded \Nby a layer of smooth muscle.
Dialogue: 0,0:00:52.44,0:00:56.37,Default,,0000,0000,0000,,In people with asthma, the airways\Nare chronically inflamed,
Dialogue: 0,0:00:56.37,0:01:00.10,Default,,0000,0000,0000,,which can make them hyper-responsive\Nto certain triggers.
Dialogue: 0,0:01:00.10,0:01:03.30,Default,,0000,0000,0000,,Some of the many asthma triggers\Ninclude tobacco smoke,
Dialogue: 0,0:01:03.30,0:01:04.42,Default,,0000,0000,0000,,pollen,
Dialogue: 0,0:01:04.42,0:01:05.21,Default,,0000,0000,0000,,dust,
Dialogue: 0,0:01:05.21,0:01:06.14,Default,,0000,0000,0000,,fragrances,
Dialogue: 0,0:01:06.14,0:01:07.07,Default,,0000,0000,0000,,exercise,
Dialogue: 0,0:01:07.07,0:01:08.10,Default,,0000,0000,0000,,cold weather,
Dialogue: 0,0:01:08.10,0:01:09.70,Default,,0000,0000,0000,,stress,
Dialogue: 0,0:01:09.70,0:01:11.48,Default,,0000,0000,0000,,and even the common cold.
Dialogue: 0,0:01:11.48,0:01:14.92,Default,,0000,0000,0000,,When people with asthma are exposed\Nto these triggers,
Dialogue: 0,0:01:14.92,0:01:19.54,Default,,0000,0000,0000,,an asthma attack, or exacerbation,\Ncan occur.
Dialogue: 0,0:01:19.54,0:01:24.61,Default,,0000,0000,0000,,But how exactly do such everyday factors\Nlead to an asthma attack?
Dialogue: 0,0:01:24.61,0:01:26.100,Default,,0000,0000,0000,,If an asthmatic is exposed to a trigger,
Dialogue: 0,0:01:26.100,0:01:30.97,Default,,0000,0000,0000,,the smooth rings of muscle that circle\Nthe small airways in their lungs
Dialogue: 0,0:01:30.97,0:01:33.75,Default,,0000,0000,0000,,contract and become narrow.
Dialogue: 0,0:01:33.75,0:01:36.93,Default,,0000,0000,0000,,Simultaneously, the trigger\Nworsens inflammation,
Dialogue: 0,0:01:36.93,0:01:40.05,Default,,0000,0000,0000,,causing the mucosal lining\Nto become more swollen
Dialogue: 0,0:01:40.05,0:01:42.70,Default,,0000,0000,0000,,and secrete more mucus.
Dialogue: 0,0:01:42.70,0:01:44.19,Default,,0000,0000,0000,,Under normal conditions,
Dialogue: 0,0:01:44.19,0:01:49.50,Default,,0000,0000,0000,,the body uses this mucus to trap\Nand clear particles, like pollen or dust,
Dialogue: 0,0:01:49.50,0:01:51.23,Default,,0000,0000,0000,,but during an asthma attack,
Dialogue: 0,0:01:51.23,0:01:57.53,Default,,0000,0000,0000,,it blocks the narrowed airways,\Nmaking it even harder to breathe.
Dialogue: 0,0:01:57.53,0:02:00.64,Default,,0000,0000,0000,,These effects lead \Nto this symptoms of asthma.
Dialogue: 0,0:02:00.64,0:02:04.97,Default,,0000,0000,0000,,Smooth muscle constriction results\Nin the feeling of chest tightness.
Dialogue: 0,0:02:04.97,0:02:08.64,Default,,0000,0000,0000,,Excess mucus and increased inflammation\Ncan cause coughing.
Dialogue: 0,0:02:08.64,0:02:10.05,Default,,0000,0000,0000,,And the wheezing noise?
Dialogue: 0,0:02:10.05,0:02:12.58,Default,,0000,0000,0000,,That happens because \Nas the airways constrict,
Dialogue: 0,0:02:12.58,0:02:18.47,Default,,0000,0000,0000,,air whistles as it passes through\Nthe narrowed space.
Dialogue: 0,0:02:18.47,0:02:22.19,Default,,0000,0000,0000,,These symptoms may make a person\Nfeel like they're running out of air.
Dialogue: 0,0:02:22.19,0:02:25.28,Default,,0000,0000,0000,,Yet counterintuitively, \Nduring an asthma attack,
Dialogue: 0,0:02:25.28,0:02:29.46,Default,,0000,0000,0000,,the inflammation can make it harder\Nto exhale than inhale.
Dialogue: 0,0:02:29.46,0:02:33.59,Default,,0000,0000,0000,,Over time, this leads to an excess\Nof air in the lungs,
Dialogue: 0,0:02:33.59,0:02:36.34,Default,,0000,0000,0000,,a phenomenon known as hyperinflation.
Dialogue: 0,0:02:36.34,0:02:40.53,Default,,0000,0000,0000,,The trapping of air inside the lungs\Nforces the body to work harder
Dialogue: 0,0:02:40.53,0:02:43.28,Default,,0000,0000,0000,,to move air in and out of them.
Dialogue: 0,0:02:43.28,0:02:49.35,Default,,0000,0000,0000,,Over time, this can lead to reduced oxygen\Ndelivery to the body's organs and tissues.
Dialogue: 0,0:02:49.35,0:02:52.67,Default,,0000,0000,0000,,Sometimes, in untreated \Nsevere asthma attacks,
Dialogue: 0,0:02:52.67,0:02:54.53,Default,,0000,0000,0000,,the body can't keep up,
Dialogue: 0,0:02:54.53,0:02:58.10,Default,,0000,0000,0000,,which can lead to death from\Nlack of oxygen.
Dialogue: 0,0:02:58.10,0:03:01.88,Default,,0000,0000,0000,,So how do we prevent these uncomfortable\Nand potentially fatal attacks
Dialogue: 0,0:03:01.88,0:03:04.03,Default,,0000,0000,0000,,in people who have asthma?
Dialogue: 0,0:03:04.03,0:03:07.39,Default,,0000,0000,0000,,One way is to reduce the presence\Nof triggers.
Dialogue: 0,0:03:07.39,0:03:10.35,Default,,0000,0000,0000,,Unfortunately, the world \Nis an unpredictable place
Dialogue: 0,0:03:10.35,0:03:13.89,Default,,0000,0000,0000,,and exposure to triggers can't\Nalways be controlled.
Dialogue: 0,0:03:13.89,0:03:18.72,Default,,0000,0000,0000,,This is where inhalers, the primary\Ntreatment for asthma, come in.
Dialogue: 0,0:03:18.72,0:03:23.69,Default,,0000,0000,0000,,These medications help asthmatics both\Ncontrol and prevent their asthma symptoms.
Dialogue: 0,0:03:23.69,0:03:27.42,Default,,0000,0000,0000,,Inhalers transport medication along\Nthe affected airways
Dialogue: 0,0:03:27.42,0:03:33.07,Default,,0000,0000,0000,,using a liquid mist or fine powder\Nto treat the problem at its source.
Dialogue: 0,0:03:33.07,0:03:35.02,Default,,0000,0000,0000,,They come in two forms.
Dialogue: 0,0:03:35.02,0:03:36.75,Default,,0000,0000,0000,,There are reliever medications,
Dialogue: 0,0:03:36.75,0:03:40.80,Default,,0000,0000,0000,,which treat symptoms immediately\Nand contain beta-agonists.
Dialogue: 0,0:03:40.80,0:03:43.91,Default,,0000,0000,0000,,Beta-agonists relax constricted muslces,
Dialogue: 0,0:03:43.91,0:03:50.13,Default,,0000,0000,0000,,allowing the airways to widen so more air\Ncan travel into and out of the lungs.
Dialogue: 0,0:03:50.13,0:03:53.61,Default,,0000,0000,0000,,The other form of inhalers serve\Nas preventive medications,
Dialogue: 0,0:03:53.61,0:03:56.36,Default,,0000,0000,0000,,which treat asthma symptoms\Nover the long term,
Dialogue: 0,0:03:56.36,0:03:58.57,Default,,0000,0000,0000,,and contain corticosteroids.
Dialogue: 0,0:03:58.57,0:04:02.94,Default,,0000,0000,0000,,Corticosteroids reduce airway sensitivity\Nand inflammation,
Dialogue: 0,0:04:02.94,0:04:05.76,Default,,0000,0000,0000,,so asthma can be kept under control.
Dialogue: 0,0:04:05.76,0:04:08.54,Default,,0000,0000,0000,,They're also crucial in preventing\Nlong-term damage
Dialogue: 0,0:04:08.54,0:04:10.09,Default,,0000,0000,0000,,from chronic inflammation,
Dialogue: 0,0:04:10.09,0:04:12.27,Default,,0000,0000,0000,,which can cause scarring of the airways.
Dialogue: 0,0:04:12.27,0:04:15.04,Default,,0000,0000,0000,,Inhalers are known to be very effective,
Dialogue: 0,0:04:15.04,0:04:17.87,Default,,0000,0000,0000,,and have helped many people\Nlive better lives.
Dialogue: 0,0:04:17.87,0:04:20.58,Default,,0000,0000,0000,,Although we've come a long way\Nin improving how we treat
Dialogue: 0,0:04:20.58,0:04:22.56,Default,,0000,0000,0000,,and diagnose asthma,
Dialogue: 0,0:04:22.56,0:04:24.77,Default,,0000,0000,0000,,we still don't know its exact causes.
Dialogue: 0,0:04:24.77,0:04:29.40,Default,,0000,0000,0000,,We currently believe that a combination\Nof genetic and environmental factors
Dialogue: 0,0:04:29.40,0:04:30.68,Default,,0000,0000,0000,,play a role,
Dialogue: 0,0:04:30.68,0:04:33.72,Default,,0000,0000,0000,,potentially acting during early childhood.
Dialogue: 0,0:04:33.72,0:04:37.73,Default,,0000,0000,0000,,Recent research has even linked\Npoverty to asthma incidents.
Dialogue: 0,0:04:37.73,0:04:39.46,Default,,0000,0000,0000,,This may be due to reasons ranging
Dialogue: 0,0:04:39.46,0:04:43.14,Default,,0000,0000,0000,,from exposure to additional pollutants\Nand environmental irritants
Dialogue: 0,0:04:43.14,0:04:46.98,Default,,0000,0000,0000,,to difficulties in obtaining medical care\Nor treatment.
Dialogue: 0,0:04:46.98,0:04:49.14,Default,,0000,0000,0000,,As our understanding of asthma improves,
Dialogue: 0,0:04:49.14,0:04:53.97,Default,,0000,0000,0000,,we can continue to find better ways to\Nkeep people's airways happy and healthy.