Many humans who practice some kind of Natural Breathing as their primary training method do so because they lack the necessary talent in mana control for methods relying on cores or circles.
However, the majority of people who train in not only Natural Breathing but the other Primal Methods as well are related to or belong to a tribal people in either the southernmost continent, Oterra, or its sister continent, the northmost continent, Jymir.
They don't practice the Primal Methods because they can't manipulate mana as well as they need to create cores or circles. They practice those methods because it's the only thing keeping them alive.
They need the physical strength and durability those methods offer. Naturally, after ages of such lives, the different tribes have perfected their uses of the methods and developed supplementary aid to help them grow even stronger and increase their chances of survival.
The Pulse-Raising Potion might not have been made by one of those tribes. But the materials and medicines used by those tribes definitely inspired it. So, it wouldn't be a stretch to say that the Pulse-Raising Potion was originally made for innately strong, durable, and ferocious humans like those who live on the south and north poles with the extreme weather and the other beings who are strong enough to make a living there.
Anthony might have an innate physique. But it had yet to blossom or display any improvements to his raw physicality, so he was still basically an ordinary and weak human. On top of that, he was a baby.
The Pulse-Raising Potion, even if it was a weakened version brought about by attempts at replicating the original, was still powerful.
"Anthony!"
Clemence cried out in shock and worry as Anthony collapsed while clutching his heart.
'No, no, no. I knew this was a bad idea! How am I supposed to tell Vira and Thomas I killed their son like this!'
Clemence reproached himself in his mind, full of guilt. But just because he assumed the worst, he didn't stop trying to help Anthony.
Clemence flipped Anthony over to his back and put a finger to the boy's throat to measure his pulse. He couldn't believe what he was feeling. But he didn't have to believe to do something about it.
He leaned down and put his ear to Anthony's rapidly expanding and contracting chest. Even before he could touch it, Clemence heard Anthony's heartbeat like the hooves of a galloping horse.
Since it was a Pulse-Raising Potion, Clemence wasn't surprised about the area of effect. But he hadn't expected the potion to raise Anthony's pulse to the sky.
"Try to take deep breaths, Anthony!"
Clemence wasn't even sure Anthony could hear him, but he still tried to encourage Anthony to stay calm and not aggravate the heartbeat any further while he looked for something that could suppress the effects of the potion.
He ran upstairs to where most of his herbs were stored and grabbed any herb with calming effects he remembered. He also grabbed some more that might work.
Clemence didn't have time to start making an elaborate medicine, so he just grabbed the herbs Anthony could digest without worry. They were also the weakest, so they might not work, but it was better than overloading Anthony's body with positive and negative medicinal effects.
It would also be bad if he poisoned him in the process of curing Anthony's heart arrhythmia.
Clemence quickly ground a couple of herbs in the pestle before trying to feed them to Anthony. But Anthony's jaw remained tightly shut while his nostrils flared like a bull's to suck in roomfuls of air before exhaling it again.
Clemence struggled to pry open Anthony's mouth and shove the mushed herbs inside. But Anthony's jaw was locked in place like a vice. And when it finally opened, before Clemence could stuff Anthony with medicine, Anthony spoke.
"I'm. Fine."
Anthony barely managed to force the words out in between breaths. Hopefully, it would be enough to dissuade Clemence from interfering.
"Don't be ridiculous! Your heart is racing like a gazelle!"
Anthony allowed himself to be distracted for a moment as he opened his eyes and glared at Clemence, who tried to stuff him with medicine.
With bloodshot eyes and a reddening face, Anthony looked scary enough to make Clemence pause.
Seeing Clemence flinch, Anthony closed his eyes and focused on his breathing again.
With his heart rate shooting through the roof, his heart and body were pumping blood like crazy. While it put an incredible strain on his body and heart, it was also an opportunity.
With his blood circulation spiking, the oxygen and mana transported by it would also increase proportionately.
It was a little more intense than he had expected. But Anthony was confident he could handle it and keep his blood sated with oxygen and mana as long as he could concentrate on his Natural Breathing and pump air filled with mana into his body.
While it was dangerous to have his heart rate so high, it was also an opportunity.
His heart had already beaten more times than it did during an ordinary day with moderate exercise, which meant he could have made the same amount of progress with his body strengthening as he did during an entire day.
However, since he had to stop Clemence from interfering, he had lost out on several precious moments, which had also strained his body further since it was pumping oxygen-poor blood. His body also tried to drain his lungs from the oxygen and mana he breathed in, but there was nothing to drain, so his lungs bore the brunt of his body's craving for oxygen.
Fortunately, it seemed like Clemence understood that Anthony knew what he was doing this time and stayed back to monitor before intruding again. But he still had medicine in hand, ready to come to Anthony's aid.
Clemence chewed the insides of his cheeks in worry as Anthony's flushed body lay on the ground. Anthony took breaths larger than what Clemence thought was possible, but he didn't seem to be gasping for air or suffocating. He seemed to be enduring, at least for now. So, Clemence got started on preparing a more complex medicine to slow down his heartrate should the need arise.