Should You Trust How You Feel or Your Data? (Myth: Feelings Are Unreliable)

Myth: How you feel is too unreliable to guide training. Only objective numbers, like heart rate, HRV, or a wearable's readiness score, can tell you what's really going on.

Why athletes believe this

It's easy to see where the idea comes from. Feelings are messy. A bad night of sleep, a stressful day, or one frustrating session can color everything. Meanwhile, devices give you clean numbers with decimal points, and numbers look like truth. Plenty of athletes have also had the experience of feeling great and then struggling, or feeling flat and setting a personal best, which makes their own perception seem untrustworthy.

What the research actually shows

Subjective measures hold up better than most people expect. A 2016 systematic review in the British Journal of Sports Medicine compared self-reported measures (mood, perceived stress, soreness, fatigue) with objective markers like blood tests and heart rate. The self-reported measures generally tracked changes in training load as well or better than the objective ones.

Ratings of perceived exertion (RPE) are a good example. A simple 1 to 10 rating of how hard a session felt, multiplied by its duration, is widely used by coaches and sport scientists to estimate training load. Using RPE to track training covers how to apply it.

That doesn't make feelings perfect. A single day's rating can be thrown off by things that have nothing to do with training. The strength of subjective data shows up in patterns over time, compared against your own baseline.

Objective data has blind spots too. A device can tell you your heart rate variability dropped, but it can't tell you that your mind is somewhere else because of a family situation. Your own rating captures context a sensor can't.

What to do with this

Treat how you feel as data worth recording. Rate it consistently, on the same scale, at the same time of day, which is all it takes to track sleep and soreness without a wearable. If you use a wearable, put the two side by side and notice when they agree and when they don't. Those disagreements are often where the most useful questions come from: "My watch says I'm recovered, but I feel wrecked. What's going on?"

Neither source gets to decide for you. They're both inputs to your own judgment, and using them well is part of the difference between training hard and training smart.

Record both in one place

You can track this in any log. Sherpa is a free athlete journal that captures how you feel before and after training, so your subjective data builds into patterns you can actually see. Download Sherpa free on the App Store.