I’ve been lifting weights for over 30 years, but I can still remember the first time I felt the pump.
Testosterone coursing through my veins.
The sleeves on my shirt bursting.
People screaming.
Okay, maybe I’ve exaggerated this experience as the years have grown into decades, but let’s just say it felt fucking fantastic.
“The pump is like the feeling of cumming. It feels just as good. So how lucky am I? Because I am getting to cum at home, and also in my workout, and all day long!”
– Arnold Schwarzenegger
(I hope you read it in his voice!)
So what causes this to happen?
Well, here’s where things get weird, because most people (even many experienced weightlifters) believe that “the pump” is a result of blood filling up your muscles, and that’s dead wrong!
The pump is actually caused by interstitial fluid, which is a solvent-like solution which sits just outside of the muscle cells. It consists of water, salt, amino acids, cellular waste, coenzymes, hormones, neurotransmitters, white blood cells, sugar, and fatty acids, and it makes up about 26% of all the liquid in your body.
This fluid spills into your muscles when via a process called osmosis.
When you are performing an exercise the body begins breaking down nutrients in order to use them for fuel, and this creates a build-up of waste products inside the muscle cell (metabolites). It’s these metabolites which eventually trigger the interstitial fluid to temporarily rush inside your muscle cells, allowing you the privilege of spending the next 30-45 minutes looking as awesome as Rambo face-fucking a tank with a Molotov cocktail.
