My last six months: one interval session a week and a lot of zone 2

Why I did this

Last fall I decided to try something new. After many years with different training programs — from hard weeks with two and three quality sessions to more theoretically grounded block periodization — I landed on a simple model: one proper interval session a week, and the rest in zone 2.

I wanted to test whether doing less, but holding what I do at top quality, would actually give better form and more energy than pushing on with more hard days. The short answer is yes. The long answer is in the numbers below.

The numbers from the last six months

I went through every training file from November 2025 to April 2026. Here are the most important numbers:

It looks like a lot of sessions, but remember that much of the cycling is commuting to and from work. They are not hard sessions — just movement in zone 1 and low zone 2. The important thing is that I held the structure — one planned hard session a week, and the rest easy — through the entire period.

Where I have actually been

If I distribute all training time across heart rate zones, it looks like this:

It's a classic low-intensity-dominant distribution: nearly two thirds of the time in zone 1 and 2, and less than one tenth in the threshold zone. What's interesting is how little time I actually spend on the hard work — one session a week is a small fraction of the total, but it's enough to keep top form ticking over.

The one interval session

The structure of the hard session varies from week to week, but the principle is the same: one session a week where I go for it. The most-used formats:

• 4×12 min at 95–100% of FTP, 4 min rest
• 3×15 min at 95–100% of FTP, 5 min rest
• 5×8 min at 100–105% of FTP, 3 min rest
• 2×20 min sweet spot (88–93% FTP) when I need a more controlled session

I choose the format based on how the legs feel during the warm-up. If I have good energy, I go for the toughest one. If I'm a bit empty, I pick sweet spot or something shorter. The point is that the session has to be hard enough to deserve the name, but not so hard that it wrecks the rest of the week.

How it feels

The most important result is not a number. It is that I have surplus energy. Every day. I look forward to my training sessions, I'm not tired in everyday life, and when I get to the one hard session of the week I always have the energy to deliver quality.

It is a difference I notice physically and mentally compared to earlier years. Before, I often did too many hard days, and even if the volume looked impressive on paper, I was tired most of the time. Now I am in better shape with less load, because the load I give is high quality and the body has time to absorb it.

What I take with me

Three things I am sure of after these six months:

• One hard interval session a week is enough to maintain and build form, as long as it is properly hard and you actually keep the rest of the week at low intensity.
• Zone 2 is not just something you do in the base period. It is the foundation for the entire year, and it is precisely the low intensity that makes the one hard session work.
• If you have to choose between making one session a bit too hard or skipping it because you are too tired, you have already made a mistake earlier in the week.

This is the principle I am building ZoneDeux on. It is not a new principle — it is the same thing elite athletes have been doing for decades — but it is underused among amateurs who often copy percentage distributions without understanding that it is the low intensity, not the high intensity, that is the key.