Using RPE and HRV to Guide Rehab and Performance

Oct 1

One of my long-time clients, Sarah, came to me confused.

She was rehabbing her hamstring and doing everything “by the book.” Set plan, structured workouts, consistent effort. But some days the same exercise felt like nothing, and other days it felt like dragging a sandbag through quicksand.

“Am I just being lazy?” she asked.

Not at all. Sarah wasn’t inconsistent. Instead she was ignoring two of the best feedback tools we have in performance and rehab: RPE (Rate of Perceived Exertion) and HRV (Heart Rate Variability).

Here’s the truth: the body isn’t a robot. The same workout can land very differently depending on sleep, stress, recovery, even hydration. That’s why relying only on fixed percentages (“3 sets of 10 at 70% max”) sometimes backfires. RPE and HRV give us real-time context.

Think of RPE like your internal fuel gauge. It’s simple, you rate the difficulty of a set or session on a 1–10 scale. Research shows RPE is surprisingly reliable, even in strength training, and correlates closely with objective markers like heart rate and blood lactate (Foster et al., 2001; Helms et al., 2016). If your program calls for “RPE 7,” that might mean 200 pounds today and 180 pounds tomorrow… and that’s okay. You’re matching the effort, not chasing arbitrary numbers.

Now, HRV is like your body’s readiness score. High variability between heartbeats generally means your nervous system is recovered and adaptable; low variability means you’re under stress or not fully recovered. Multiple studies show HRV-guided training reduces injury risk and improves performance in both endurance and strength athletes (Stanley et al., 2013; Flatt & Esco, 2016). The beauty? You don’t need lab equipment anymore, wearables and apps make it easy to track each morning. (I personally like the Whoop)

So how did we use this with Sarah? Instead of blindly following a rigid plan, she started checking HRV each morning and using RPE in her workouts. On high HRV days, we pushed intensity. On low HRV days, we kept the volume lighter but still moved. Active recovery instead of forced intensity. Within a month, she wasn’t just pain-free, she was back sprinting, with fewer flare-ups and more confidence.

Here’s the point: rehab and performance aren’t just about doing more. They’re about doing the right amount, on the right day, for your body. RPE and HRV are two of the simplest ways to listen to that feedback.

If you want a quick, easy explainer, this video breaks down HRV in under 4 minutes: YouTube: What is HRV and Why Does It Matter?

Sarah’s story is one I see every week. Athletes aren’t “inconsistent”—they’re human. By paying attention to how hard the work feels (RPE) and how ready the body is (HRV), you can train smarter, recover faster, and avoid the cycle of overtraining or re-injury.

So if you feel like your workouts swing between effortless and impossible, it’s not a weakness. It’s feedback. The question is are you listening? If you want to talk about building a training plan that is right for your body and goals, make an appointment at the MVMT Lab today!

References:

  • Foster, C., et al. (2001). A new approach to monitoring exercise training. J Strength Cond Res, 15(1), 109–115.

  • Helms, E. R., et al. (2016). RPE-based autoregulation in resistance training: current status and future directions. Sports, 4(2), 35.

  • Stanley, J., et al. (2013). Heart rate variability is associated with training load and performance in elite endurance athletes. Eur J Appl Physiol, 113(2), 467–475.

  • Flatt, A. A., & Esco, M. R. (2016). Evaluating individual training adaptation with smartphone-derived heart rate variability in a collegiate female soccer team. J Strength Cond Res, 30(2), 378–385.