Aryna Sabalenka's path to the US Open final revealed something trainers and athletes already suspected: elite tennis demands extreme physiological stress. Women's Health obtained exclusive access to Sabalenka's Whoop data during her run to the final, and the numbers expose just how much recovery science influences top-level performance.
Whoop is a wearable that tracks heart rate variability, sleep, and strain metrics. These data points tell the story of what happens inside an athlete's body during tournament play. For Sabalenka, the numbers painted a picture of sustained, near-maximum effort across multiple matches played on consecutive days with minimal rest.
The US Open format means players compete for two weeks straight, moving through rounds that increase in difficulty. Each match lasts anywhere from 45 minutes to over three hours. Sabalenka, ranked among the world's top players, faced opponents trained to exploit any physical decline. The Whoop data showed elevated heart rate variability recovery periods between matches, indicating her nervous system was working overtime to bounce back.
What stands out most is the strain load. Whoop measures strain as a number from 0 to 21, reflecting cardiovascular and metabolic stress. During tournament play, Sabalenka's strain scores climbed into the upper ranges on match days. Recovery between matches didn't fully return her metrics to baseline, suggesting cumulative fatigue built throughout the tournament. This cumulative effect matters because tennis is a sport where split-second decision-making and explosive movement determine outcomes. Fatigue degrades both.
Her sleep data proved equally telling. Players aiming for peak performance need seven to nine hours nightly, but tournament schedules, travel, and post-match adrenaline make this difficult. Sabalenka's Whoop data showed nights where total sleep dipped below optimal levels, yet her team managed her recovery through other interventions. Cold plunges, massage, compression sleeves, and nutrition timing all work together to accelerate nervous system recovery when sleep alone isn't enough.
The reason this matters beyond tennis is methodological. Whoop and similar wearables give athletes and coaches real-time feedback on readiness. Rather than guessing whether an athlete recovered enough, data offers objective insight. A low heart rate variability score signals the nervous system needs more recovery time. A high strain score on consecutive days flags overtraining risk. Elite programs now make daily training and competition decisions based on these metrics.
For Sabalenka specifically, reaching the US Open final meant pushing through matches where her body signaled fatigue while her competitive drive pushed harder. The Whoop data quantifies what fans see on screen: a player operating at the edge of what human physiology allows.
This transparency also changes how we think about athlete performance narratives. Commentators often attribute wins to mental toughness or willpower. The data suggests physiology matters more. An athlete can possess unshakeable mental strength, but if heart rate variability is tanked and strain is maxed out, performance declines regardless of mindset. Recovery science and wearable technology are forcing sports to reckon with this biological reality.
Sabalenka's data release serves teams, coaches, and individual athletes pursuing their own peaks. It normalizes performance monitoring and demonstrates that reaching elite levels requires systematic attention to recovery metrics, not just training volume.