Yup that’s me.
You might be wondering how I ended up in this situation.
So I’m training for a marathon.
I’m 15 miles into this run.
I have another 7 to go.
I’m losing steam.
My legs are cramping.
I can barely breathe.
I don’t know if I can make it another mile.
What happened?
You basically need three things to run a marathon: energy, oxygen and water.
Our bodies mainly use the sugar glucose for energy.
We store it in big blobs called glycogen that can hold 30,000 glucose molecules.
Building up glycogen is the basis for carbo-loading or carbing up.
That’s when runners eat loads of carb-heavy meals, cramming as much glucose into their
cells in the days before a race.
Sounds like a great excuse to eat a bunch of pasta, but studies show it actually does
work to increase your energy stores.
Runners need oxygen too.
First to, you know, live.
But second because it’s key to using glucose efficiently.
Our cells use oxygen in the reactions that break down glucose.
Aerobic respiration, which relies on oxygen, is about 20 times more efficient than anaerobic
respiration, which does not use oxygen.
Aerobic activity like distance running, cycling, cross-country skiing has you breathing in
a lot to keep going.
Anaerobic activity is short & fast, like sprinting or weight-lifting.
Oxygen fuels our body’s breakdown of glucose to water and carbon dioxide.
Training increases the amount of oxygen your body takes in and your cell’s ability to
use it.
All that makes for more efficient use of last night’s pasta.
When you start getting out of breath, your body is falling behind on the cleanup of waste
products from burning all that fuel.
That can lead to fatigue.
As your aerobic respiration rates drop, your cells can only break glucose in half.
That makes lactic acid.
It’s a myth that lactic acid leads to muscle soreness.
But the higher acidity inside your cells does disrupt biological processes.
That’s why your brain tells your legs they are on fire: it wants you to slow down and
catch your breath.
You can run low on glucose too.
Runners like to say they’ve “bonked” when they run out of glycogen.
It tends to happen around mile 20 (about 32 km), which is when many distance runners feel
like they hit “the wall.”
When that happens, your cells start breaking down fatty acids make more energy.
Endurance athletes who have trained properly can “break through the wall” more smoothly
and keep on truckin’.
Hitting the wall unprepared can be dangerous.
Breaking down fatty acids form ketones, which can trip a process that drops your pH and
causes dehydration - this tires you out faster.
And then there’s water.
One of water’s most important functions is keeping you cool.
When you sweat, liquid water on your skin evaporates, turning into water vapor.
The energy that water molecules take into the gas phase comes from your body’s heat.
That’s how sweating cools you off - it literally pulls heat away from your body.
Sweat also gets rid of salts.
When we’re glistening heavily we can run low on salts, which is why sports drinks contain
sodium chloride, calcium chloride, potassium phosphate and other salts, AKA electrolytes.
Yup, electrolytes are just salts.
It is possible to drink too much water.
When you drink more than you’re sweating out, it can lead to hyponatremia, a dangerously
low sodium concentration in your blood that can cause your brain to swell.
Not.
good.
The science is still out on exactly how much and what someone should drink while they’re
running.
So it’s best to use common sense: Distance running, especially when it’s hot out, can
make you rather thirsty.
So if you want to enjoy the experience, make sure you take in some fluids when your body
says that would feel nice, thanks.
So long distance running is really hard, especially if you haven’t trained properly.
But there is a payoff--and I don’t just mean the space blanket and free food at the
finish line.
Some people may recognize a feeling of euphoria after a grueling workout, often called a “runner’s
high.”
Recent research shows a connection between the euphoria and the brain’s endocannabinoid
system, the same one that responds to the active ingredient in pot: THC.
Scientists have found high levels of a THC relative called anandamide in runners’ blood
after they work out.
That leads to an increase of every brain’s favorite molecule and the one that results
in the “high”: dopamine.
Some of us at Reactions, really dig this distance running thing.
Others -ahhhh- not so much.
Are you a runner?
Or are you more of a couch-based athlete?
Let us know in the comments, along with your other sports chemistry questions.
Thumbs up and subscribe on the way out, we’ll see you again soon.