Training Readiness: what it is and why it changes everything

You scored 72 on the battery. Green. Feels like a go-signal.

But you’ve trained hard the last three days in a row. Your legs are heavy. You slept fine, but your HRV has been trending down all week.

Should you push today?

The Battery Score says yes. Training Readiness says not so fast. And understanding the difference between those two things is one of the most useful shifts you can make in how you train.

The gap that the battery score doesn’t fill

The Battery Score is a snapshot. It answers: How is my body doing right now, this morning? Sleep quality, HRV relative to baseline, activity from yesterday — all combined into a single number that reflects your current state.

That’s genuinely useful. But it doesn’t answer a more specific question: If I train hard today, will my body actually respond positively to that stress?

Those are two different questions. You can be reasonably well-recovered (decent battery) but still in a state where adding more training load will just dig the hole deeper instead of making you stronger. And you can have a moderate battery score but be in a great position to absorb a tough session because your trend is moving in the right direction.

Training Readiness is the answer to the second question.

How it’s calculated

Training Readiness pulls from four inputs:

1. 3-day HRV trend. Not just today’s HRV reading, but whether it’s been going up, flat, or down over the last three days. A single good reading means less than a consistent upward trend. A single low reading is far less concerning than three consecutive drops.

2. HRV vs. your personal baseline. How does today’s reading compare to your 14-day rolling average? This is the same calculation the battery score uses, but here it’s one input among several rather than the dominant signal.

3. Sleep quality over the last 48 hours. One bad night is manageable. Two consecutive nights of poor sleep consistently impairs the body’s ability to generate training adaptations — not just performance, but actual physiological adaptation.

4. Accumulated strain. How much load have you put on your body over the last 3 days? High cumulative strain, even spread across days that each felt manageable, adds up. This is what catches the “I’ve been training hard all week and feel fine” trap.

The three states

Push

Your trend is positive, HRV is at or above baseline, sleep has been solid, and you haven’t accumulated excessive load. This is the green light. Not just to train, but to train with intent — to go after intensity, push PRs, run the harder intervals. Your body is in a state where stress will produce adaptation.

Don’t waste Push days on easy sessions because you “don’t feel like it.”

Maintain

Something is slightly off — maybe HRV is below baseline, or you’ve had two hard days in a row, or sleep was rough last night. Not bad enough to skip training, but not a day to push new limits. This is the most common state for people who train consistently.

On a Maintain day: do the session, keep intensity at 70–80%, skip the max efforts. You’re maintaining fitness without digging a deeper hole.

Rest

Three or more signals are pointing the wrong way simultaneously. HRV trend down, accumulated strain high, sleep quality poor. Adding more load right now won’t produce adaptation — it’ll produce fatigue or injury risk. Rest days aren’t wasted days. They’re when the adaptations from your previous training actually consolidate.

The example that makes it click

Here’s the scenario from the top of this post, unpacked.

Battery score: 72. Green. Sleep last night was decent — 7.5 hours, reasonable HRV of 58ms. On its own, this morning looks fine.

But zoom out three days. You trained hard Monday, Tuesday, and Wednesday. Your HRV was 68ms on Monday morning, 61ms Tuesday, 58ms Wednesday, 58ms today. That’s a flat-to-declining trend over four days. And you’ve accumulated three consecutive days of above-average strain.

Battery score: 72 (green) — accurate. Your body is reasonably recovered from yesterday specifically.

Training Readiness: Maintain — also accurate. Your body doesn’t have the adaptive capacity to absorb another hard session right now, even though you’re not in the red.

Take Thursday easy. By Friday, the HRV trend reverses, the accumulated strain clears, and you get a Push signal. That Friday session will be more productive than anything you’d have forced on Thursday.

Why this is a PRO feature

Training Readiness requires a reliable baseline to be meaningful. Comparing your HRV trend to your personal baseline — rather than to a population average — is what makes the signal accurate for you specifically.

That baseline takes at least 14 days to establish. During those early days, Readiness calculations would be based on too little data to be trustworthy, and a wrong Readiness signal is worse than no signal. So Capacity waits until the baseline is solid before surfacing this feature.

Once you have it, the use case is simple: open Capacity in the morning, check your Readiness state, and let it inform how you approach the day’s training. Not dictate — inform. You still decide. But now you’re deciding with better information.

That’s the whole point.