For professional gravel cyclist Isabel King, battling heat and peanut-butter-thick mud during UNBOUND Gravel, a 207-mile race through the Flint Hills of Kansas, was nothing new.
The LA-based endurance athlete had completed this race four times before and was accustomed to spending 10-plus hours in the saddle.
This year, though, she had a fresh challenge to face when she rode up to the start line at the end of May: figuring out how to manage pumping breast milk as a nursing mother while racing.
Following the birth of her daughter, Hazel, last August via cesarean section, King’s approach to racing took on a new direction.
For one thing, she was acutely aware that her own fueling and tapering (the practice of reducing mileage in the weeks leading up to a race) probably looked different from her fellow racers.
“I joked that I was the only one in the Peloton that my taper into the race included spreading out my pumping sessions for breastfeeding,” King told The Post.
She also predicted she’d need a pit stop to pump. With a newborn, moms typically need to breastfeed or pump every two to three hours. Going much longer can leave the breasts painfully full and, in some cases, contribute to inflammation and mastitis.
As babies get older and begin eating solid foods, they generally nurse less often — meaning moms may go longer between feeds or pumping sessions.
As the race grew closer, King’s plan was to ride for eight hours nonstop — then pause at an aid station 150 miles in to pump before she finished.
But her body had other ideas, and she didn’t stop to pump after all. Instead, she completed a grueling 12 hours and 17 minutes on her bike through a four-hour downpour and intermittent lightning, crossing the finish line before taking care of her breast milk.
“It was getting really hot, and if I stopped, it was going to be really hard to get going again,” she explained. “I was like, ‘We’re going to risk it, we’re going to try and get to the end.’”
A new fueling strategy
When it came to properly fueling for the race and her training sessions, King had to switch things up from her pre-baby days. Back then, she relied on energy gels, packets of concentrated carbs, electrolytes and sometimes caffeine designed to fuel endurance athletes on the go.
“When I was pregnant, I switched to a little bit more real food because I was wary of not just eating straight sugar,” she said.
Despite having experience with the type of hunger that comes after long rides, King was still surprised by the appetite she developed while breastfeeding.
“[People said,] ‘You could have sold that liquid gold’… I live in LA, there are bodybuilders everywhere, I could be making a fortune!”
Isabel King
Balancing recovery from the C-section, producing breast milk and fueling her body for training, she compared her insatiable hunger to doing a 200-mile race every day and forgetting to eat.
“I was the hungriest I had ever been in the first two to three months after giving birth,” she said. “There was no amount of protein that I could eat that would satiate this crazy hunger.”
On race day, she drank eight 30-ounce water bottles with 75 grams of carbs from her fuel sponsor, CarbsFuel, plus three 1.5 liter packs of plain water. She also had 13 energy gels containing a mix of caffeinated, salted and plain, all 50 grams of carbs.
“Plus two fig bars and a handful of M&M’s,” she added.
From the gels and sports drink mixes alone, she ended up consuming 1,250 grams of carbohydrates, a number that was lower than many other cyclists that day.
As for her breast milk, her plan was to “pump and dump” what she jokingly dubbed her “Red Bull for babies” milk, knowing it would contain caffeine from the gels and sports drinks she’d consumed during the race.
“I mentioned [on social media] that I poured out the milk I made during the race, and I got a few comments that were like, ‘You could have sold that liquid gold professional-athlete-made breast milk,’” she said. “I live in LA, there are bodybuilders everywhere — I could be making a fortune!”
Breastfeeding while racing
When she eventually pumped after crossing the finish line, King produced about 3 ounces — much less than her usual amount of 14. She believes the physical stress of the race temporarily affected her milk production, although she didn’t know that was happening at the time.
While endurance exercise generally doesn’t stop breast milk production, factors involved in intense exercise — like dehydration, fueling and physical stress — can have an affect.
Another concern on her mind about going so long without pumping was the risk of clogged milk ducts.
She’d previously experienced mastitis, an inflammation of breast tissue common in breastfeeding women that can cause flu-like symptoms, breast pain and engorgement.
Fortunately, she got lucky with both her daughter’s preference for bottled milk over breastfeeding and the amount of milk she produced.
“I was a really big over-supplier even when I was nursing [and] built up a big store of freezer milk,” King explained.
“I could slow the milk supply down pretty strategically with pumping, going into this knowing that I was going to have to go eight hours at least without it.”
She even brought extra frozen milk as a backup, a saving grace because she didn’t want to risk trying formula for the first time in case her daughter didn’t like it.
Even though she’d experienced the pain that can come with clogged ducts, King was in sensory overload while riding and couldn’t tell if she needed to pump or not.
“I have a Camelbak on, and a sports bra and it’s hot… so it was a weird sensory experience,” she said, noting that she didn’t feel the engorged sensation that typically comes when going too long between feeding or pumping.
And despite still having four hours left to race, she decided to take a chance and push through to the end.
It took three days for her milk supply to return to normal after the race. But her recovery process told a different story.
Her heart rate variability (HRV) — the small variations in time between consecutive heartbeats — from her Garmin watch data suggested that her body was struggling to balance breastfeeding with recovery from the demands of endurance training.
She eventually made the choice to fully stop breastfeeding six weeks later so she could attempt future races feeling her best physically.
The day she stopped, her HRV went up and her Garmin said she was ready to train again.
