Eventing horses are athletes.

Just like any athlete, there are many aspects to their training and hours of preparation for each event.

Fitness and conditioning is one of the most important details for an event horse. Horses have to be able to gallop and jump for long periods of time over a cross-country course and compete in multiple events over the course of three days.

Heart-rate monitors, like the ones made by Polar and Hylofit, help make that process a little easier for riders. The technology has existed since the 1980s and is only getting better.

For Lauren Billys, based out of Carmel Valley, California, preparing for an event like the one at Rebecca Farm is a six-month process.

She’s used a heart-rate monitor made by Polar for the past three years.

“I will plan the shows that I’m going to go to but more importantly I plan my fitness out,” Billys, who competes at CCI4*-Long said.

“It helps me monitor how I bring my fitness up so it matches with my plans and helps me regulate my plans for this event.”

Billys is vying for a spot in the 2020 Tokyo Olympics representing Puerto Rico. Rebecca Farm is a qualifying event for Billys, who has to be ranked in the top 2 in the southern hemisphere to get to the Olympics since she isn’t competing for a spot on a team but as an individual. Billys and her horse, Castle Larchfield Purdy, or Purdy as he’s known around the stable, have already been to the Olympics once, in the 2016 Rio Olympics.

Rebecca Farm is known as a championship level, or long course, similar to the Olympics. Those cross-country courses are close to 4 miles long. Horses are also required to average 570 meters per minute and riders have to make adjustments constantly.

“You’re going 25 miles an hour the whole time and just sucking wind,” Billys said.

A horse at rest will typically have a heart rate around 36-40 beats per minute, or BPM. While galloping through a cross-country course or during conditioning gallops, than can spike to as much as 200 BPM, known as the anaerobic stage, where there isn’t enough oxygen present to flush lactic acid out of the muscles. The fitter a horse is, the easier this gets and it spends more time in the aerobic zone. For horses, the aerobic stage is somewhere between 165-180 BPM.

Eventers typically train on hills to build and gauge a horse’s fitness.

“It’s just like humans doing HIIT training,” Shannon Lilley of Team Lilley Eventing said.

“It builds so much endurance without breaking down too much.”

Lilley has represented the United States in the 2011 Pan Am Games and is competing in CCI3*-Long at Rebecca Farm on her horse Greenfort Carnival, also known as Eddie.

Lilley, based out of Santa Cruz, California, uses Hylofit, which is a brand new heart-rate tracking technology. There are sensors for the horse and the rider, tracked through an app.

“I‘ve used it for my gallops to prepare for this and it’s interesting to see how the horses progress,” Lilley said.

“I’ve prepared for a lot of different long formats and a lot of different horse shows. It’s nice to know where you are. It’s just like doing anything else. I work with a heart rate monitor for myself because I run so it’s nice to know where your horses are.”

Where Lilley’s Hylofit tracks horse and rider, the Polar model only tracks the horse’s progress. The Hylofit pairs with Garmin fitness and Apple watches, but doesn’t show the human’s HR on the Garmin. It’s something the company is working on based on feedback from riders.

Riders cannot use GPS trackers in competition, though some riders in lower levels may secure special permission to do so. For riders like Billys and Lilley, that would be unusual. But based on the depth of knowledge each has of her horse’s training, a heart-rate monitor isn’t necessary since they already know where their horses are in their conditioning.

The Polar model wraps all the way around the horse’s girth area, while the Hylofit snaps into the left side of the girth.

“You don’t even notice it’s there,” Lilley said.

“It doesn’t bother your leg.”

Prices for both types of HR monitors run between $250-500, but for the riders, it’s worth every penny.