What 'Intensity ▮▮▮' means and how to self-regulate it

Every session header in the plan carries an intensity meter — one bar, two or three. It's the most important instruction in the session and the easiest one to skim past on the way to the exercise list.

The exercises tell you what to do. The meter tells you how hard, and getting that wrong in either direction is what turns a well-designed month into a mediocre one.

The three bars, translated

One bar is easy work you could sustain for a long time. Full conversation, nose breathing possible, roughly a four to six out of ten on a perceived-effort scale. This is Zone 2 cardio, your step target and Active Recovery days. It should feel almost too easy, which is exactly why people ruin it by going faster.

Two bars is hard and controlled. Short sentences only, deliberate breathing, around a seven to eight out of ten. This is where most of your strength work lives: sets that finish with two reps genuinely in reserve, not sets that finish with you on the floor.

Three bars is very hard and time-limited. A word or two at a time, around a nine out of ten, and not sustainable for more than the length of the work block. Intervals and finishers. If a three-bar block is comfortable at the end, it wasn't a three-bar block.

• One bar — full conversation, effort four to six of ten, could hold it for an hour
• Two bars — short sentences, effort seven to eight of ten, two reps left in the tank
• Three bars — a word at a time, effort about nine of ten, over within the work block
• Nothing in the plan asks for a ten. A ten is a failed rep or a sprint you can't repeat

Why most people get it backwards

The classic error is compression: everything ends up as a two. Easy days get pushed to a seven because a walk feels like it should be harder, and hard intervals land at an eight because a nine is genuinely unpleasant. The result is a month of medium, which is the one intensity that produces neither the recovery of the easy days nor the stimulus of the hard ones.

The fix is to protect the bottom of the scale as carefully as the top. A one-bar day is supposed to feel like it isn't doing anything — that's what makes the three-bar session on the following day possible. If your easy days and your hard days feel similar, the problem is almost always the easy ones.

For lifting: count what's left, not what you did

The cleanest way to rate a set of weights is reps in reserve — how many more you could genuinely have completed with the same form. Two left is a seven or eight. One left is a nine. Nothing left is a ten.

That framing is more accurate than asking how hard it felt, because it asks about a countable thing rather than a mood. It's also self-correcting: if you think you had one rep left and next week you get three more, you were rating your discomfort rather than your capacity, and the weight goes up.

The rule of two in this program is the same idea with the arithmetic removed. Last two reps difficult, form still intact. That's a two-bar working set.

For cardio: the talk test beats the heart-rate maths

You'll see percentage-of-maximum heart rate targets everywhere, and they're built on an age formula — 220 minus your age — that is a rough population estimate with a wide error band. Two people the same age can differ by well over ten beats, which is enough to move you a whole zone.

The talk test doesn't have that problem, because it measures you. It tracks the point where your breathing changes gear closely enough for training purposes, it needs no equipment, and it recalibrates itself automatically as you get fitter.

If you do wear a monitor, use it the sensible way round: run the session by feel and the talk test, and use the heart-rate trace afterwards as a record rather than a steering wheel. Wrist-based readings in particular lag and wander during interval work, which makes them a poor thing to chase in real time and a perfectly good thing to review later.

“Rate the reps you had left, not how much you disliked the ones you did.”

Self-regulating on a bad day

The point of an intensity target rather than a fixed weight is that your capacity moves. After five hours of sleep, or in week three of a deficit, the weight that was a two-bar effort last Tuesday might be a nine today. Chasing the number on the page rather than the effort on the meter is how good sessions become injuries.

So keep the intensity and change the load. A lighter weight at the prescribed effort is the session as designed. The reverse — the same weight at a collapsing effort with degrading form — is not.

One caveat worth stating plainly: perceived effort is a signal about training, not about health. Chest pain, unusual breathlessness, dizziness or a heart rate that stays high long after you stop are reasons to stop and see a clinician, not reasons to adjust a bar on a meter.