You can now put an exercise physiology lab in your pocket. Considering what they used to be like not many decades ago, it’s pretty unreal.

In 1965, Leroy “Bud” Getchell started an exercise physiology lab in 1965 at Ball State University. A first purchase for the lab was a Monarck ergometer. The $500 price tag raised some eyebrows within the university. Who blew half a grand on a bike with no wheels? David Costill would become the director of the lab and the age of the Ball State Human Performance Lab had officially begun. Fortunately for the endurance world, Costill would vector the lab into the realm of distance running. He brought in the greats of the era, including names like Steve Prefontaine, Frank Shorter, Derek Clayton and ultra-runner Ted Corbitt.

A $4000 grant allowed Costill to buy the first batch of technology he needed, like a Quinton treadmill, a spectrophotometer and gas analyzers—so he could study the runners’ blood, glycogen stores, fat burning capacities and also analyze muscle snatched with biopsies. The lab would ultimately get a lot of funding from drink companies, like Royal Crown Cola, Coke and Gatorade, all in search of some super-secret drink concoction. They never did find the super drink, but the money would ultimately enable the Lab to do things like buy a first computer: a Radio Shack TRS-80 with 4 kilobytes of memory and a Zilog Z80 8-bit processor.

Wow. Well, in 2017, armed with your smart phone (that can process over three billion instructions per second—roughly 120 million times faster than Apollo era computers) and a Cercacor Ember Sport Premium ($699; that can non-invasively track up to seven biomarkers simultaneously, it’s a little unreal. Without spilling all the blood and vomit all over the walls and floor like they did at the Human Performance Lab, an athlete can monitor hemoglobin values, the amount of oxygen bound to the hemoglobin, oxygen saturation, the Pleth Variability Index (the variation in your pulsing-blood to non-pulsing blood over the course of a breathing cycle) and more

Ben Hoffman—who earlier this year clocked a winning 7:58 at the Ironman Africa Championships in South Africa—recently talked about his use of the Ember over the past eight months. Hoffman says the device gives him “instant, painless feedback” on biomarkers that, when tracked over time, can steer him toward the dream of optimizing his training. “I take measurements every day. By overlaying the biomarker data from the device with the metrics from my training, I can highlight how my body is responding without having to guess.”

Unlike the 1970s when scientists like Costill were simply looking for foundational commonalities about what makes a good endurance athlete (they came to the conclusion, for example, they were skinny), we now have the technology to, as Hoffman suggests, whittle away the guessing and know, for each individual, what works and what doesn’t work.

“The future of sport is in the technology and science of the individual,” Hoffman puts it. “It’s about pushing for gains by knowing more about each person’s unique makeup.”

In particular, Hoffman says the data flow has allowed him to push himself about as far over the edge as he can with his training and know precisely when he has to pull back. “Every detail and percent matters” in this pursuit, he says. Hydration, altitude and heart rate data help him plot the boundaries.

The Ember comes with a sensor, a central unit you need to charge up, and requires the computing power of your smart phone. A new unit comes with 200 “Hemoglobin Measurement” credits that you apply toward collecting the daily hemoglobin numbers. With the free app in place and a cloud account, all the data you collect is matched by GPS info including elevation, temperature, humidity and more, charted and graphed.

How to use the Ember.