Health Is the One Asset in Our FIRE Plan I Can't Buy Back at 40 — and This Year I've Been Quietly Spending It

A few weeks ago I played football with the same guys I've played with for years, and somewhere in the second half I found out something our FIRE plan had never once mentioned.

The extra kilos, you don't notice. You see the same face in the mirror every morning and it moves half a gram a day. The broken sleep you get used to, partly because you have no choice and partly because every other parent of a small child looks equally wrecked. Neither of those tells you anything.

Sport tells you immediately. Sport is a benchmark with a memory. I knew exactly what I could do on that pitch two years ago, and I could feel, minute by minute, that I can't do it now.

I'm 28. We're six to eight years out from coast-FIRE, saving around half of our household income, buying the same boring world ETF every month. On paper the plan is in better shape than it's ever been. And this is the first year I've run a real deficit on the one line in it I can't refinance.

Health is in the FIRE plan whether you put it there or not

Our plan has a destination attached to it, which is the whole reason it works: I want to teach high-school maths and physics around 40. Not a beach. A classroom.

That's a physical job. Six hours a day on your feet, in front of thirty teenagers who can smell exhaustion from the back row. Nobody puts "can stand up all day and still be interesting at 2pm" on a net worth statement, but it's a hard requirement of the thing I'm saving for. If I arrive on schedule and can't do it, I didn't retire early. I just stopped earning.

So here's my position, and it's the one I'd defend in an argument: a FIRE date you pulled forward by borrowing from your body isn't early. It's a loan, and the 40-year-old who's supposed to collect is the one who signed for it without being asked.

The countdown I actually care about isn't to 80.

Data: Eurostat, healthy life years and life expectancy (hlth_hlye), 2023.

In Czechia, where I live, the average person gets 79.9 years of life and 62.0 of them free of activity limitation. That's a 17.9-year tail. The EU average is nearly identical: 81.4 against 63.1.

Then look at Spain. Longest life in the group at 84.0 years, and the biggest unhealthy tail at 21.9. Longer life and longer healthspan are two different purchases, and most of us only track one of them.

If I hit my number at 40, the gap between that and the average Czech healthspan is 22 years. That's the actual budget I'm working with. Not the ETF balance.

One caveat, because I'd rather say it than have someone say it for me. This metric is self-reported activity limitation from an EU survey, so it drifts with culture and with how people answer questions about their own bodies. The Czech statistical office publishes the same figures and they line up. Directionally solid, not surgically precise.

The bill for this year, itemised

I'd like to write the version where I noticed all this and fixed it. That isn't what happened, so here's what it actually cost.

Sleep. This is where I found the most uncomfortable sentence in anything I've read this year. A German team followed 4,659 parents through the SOEP panel and measured their sleep from before pregnancy onwards. Mothers lost 62 minutes a night at the three-month low point. Fathers lost 13, which sounds trivial until you read the next bit: neither mothers' nor fathers' sleep fully recovered up to six years after the first birth.

And the part that should bother a personal finance blog more than it does: they checked whether household income helped. It didn't. Nor did being two parents instead of one. Money bought us a great many useful things this year. It did not buy back a single minute of that.

We're hanging on like every other new parent, to be clear. We'd love to help our daughter sleep in longer stretches. That project is going to have to wait, and I've stopped pretending otherwise.

The chair and the car. Desk job, then a long drive home. A meta-analysis across 1.3 million people found that above roughly six to eight hours of sitting a day, each extra hour carries about 4% more all-cause mortality risk even after adjusting for how much you exercise. The Czech average commute is 27 minutes each way, the EU average 25, and I'm well above the middle of that distribution.

Here's the part I didn't expect, and it changed what I think the fix is. A separate analysis of over a million people found that sitting time carried no excess all-cause mortality in the most active quartile. The desk isn't the bill. The desk plus an untrained body is the bill. So "sitting is the new smoking" is lazy, and the currency here turns out to be movement, not a standing-desk purchase.

Food and the gym. Fewer workouts, more junk food. For most of this year that was simply true. September is the first month we got the food back under control, and the thing that fixed it wasn't discipline, it was lowering the difficulty, the same way we never upgraded the car after the baby because the tent and the Golf were already fine: slow cooker, oven, the same six recipes, cook once and eat twice. Fitness is next and it's harder, because the problem isn't finding 90 minutes, it's having the energy to not spend those 90 minutes on the couch. We're at one or two sessions a week. That's up from zero and I'm going to count it.

Then the compounding starts, which is the part nobody warns you about. You take the lift instead of the stairs. You're tired, so you move less, so you're more tired. I recognise that loop, because it's structurally identical to the one I spend my working life telling people to run in the opposite direction with their money.

The case against me is stronger than I'd like

Now the part where I argue against my own headline, because the counter-evidence is genuinely good and I'd rather lose honestly than win by not reading.

The claim "you can't buy health back" is, on the data, overstated.

A study of 315,059 adults found that people who were inactive for most of their adult lives and only became active between 40 and 61 had almost exactly the same mortality benefit as people who had been active the whole time. Hazard ratio 0.65 against 0.64. The authors' own conclusion is that midlife is not too late to start. That's a direct hit on my thesis and I'm not going to bury it in a footnote.

Then there's the study I keep coming back to, and it's only five men. Dallas, 1966. Five twenty-year-olds spent three weeks in bed for science, and it turned out that three weeks flat on their backs at 20 cost more physical work capacity than the following three decades of ageing did. Thirty years later the same five came back at 50, trained for six months, and 100% of the age-related decline in their aerobic capacity was reversed.

One hundred percent, in six months. That's the best argument against everything above, and it sits in the same paper as the best argument for it, because there's a sentence at the end. No subject reached the peak he'd hit after training thirty years earlier.

The trajectory comes back. The ceiling doesn't.

There's a second counterargument I should hand over too, since it's the obvious one on a money blog: money does buy health. Across 15 EU countries, men with less than secondary education live about seven years less at 30 than tertiary-educated men. Where you live and what you earn move healthspan by a decade. One soft year of a 28-year-old's gym attendance does not.

And working longer isn't the safe branch either. Across 603,838 people, working 55 hours a week or more carried 33% higher stroke risk than a normal week. Grinding one more year to hit the number has its own price tag. There is no zero-risk option on this decision tree, which is exactly why it has to be said out loud instead of optimised in private.

What a FIRE plan can't buy back

So I'll narrow the claim to what survives.

The trajectory is recoverable. The years aren't. I don't get this Tuesday back, and the version of me who walks into a classroom at 40 is built out of a decade of Tuesdays.

The ceiling isn't recoverable either, per Dallas. You can return to the curve. You come back at a lower point on it.

And the tail risk isn't diversifiable. Averages recover, individuals get a diagnosis. That's the bit that should actually worry a FIRE planner, because the data on how retirement timing really goes is brutal.

Data: EBRI/Greenwald 2026 Retirement Confidence Survey (US data).

46% of retirees left the workforce earlier than they had planned, and 41% of those cited a health problem or disability. Workers expect to stop at a median of 65. Retirees actually stopped at 62. It's American data, so read it as a direction rather than a Czech forecast, but the European version of the mechanism is well documented: across 11 countries in the SHARE study, poor health more than tripled the hazard of leaving work through disability benefit.

Your body already has a vote on your retirement date. It votes late, it doesn't tell you in advance, and it isn't in anyone's projection model. Including mine, and I built mine.

Would I actually take a later date to fix it?

Yes, and that one's easy. My wife and I have said it out loud at a money date more than once.

What we want isn't a date. It's a long stretch of freedom, and freedom for us means healthy free schedules. Getting there at 35 in miserable shape isn't the win. Neither is getting there at 75. I'd trade a year of the timeline for that without thinking about it, and if that offends the optimisers, so be it.

I should admit I've made this exact trade in the wrong direction before, and badly. Through most of my early twenties, roughly a six-year stretch, I was building two houses while trying to get a career started. Very hands-on, both of them. My body was a wreck. What I had instead was the vision, the goal, and the low-grade panic of two unfinished buildings standing in front of me.

Could I do that now at 28? No chance. Would I do it again? Absolutely. Those six years are the reason I carry a fraction of the financial stress most people my age are only starting to feel, and I yolo'd into them early enough that I could afford to be wrong.

That's a point about the bill, though, not an argument against it. I took that loan knowingly, it was a young man's loan, and it had a repayment date I could see. This year's version is worse, because I was running the deficit without saying it out loud.

I'm not going to end this with a morning routine

There's a version of this article that finishes with a protocol. Five a.m., cold water, a habit tracker. I'd be lying, and you'd know it within a paragraph.

Here's the actual state of things. I need to lose around 15 kilos and I know exactly what that takes, none of which is a secret. We fixed the food in September by making cooking easier, not by becoming stronger people. Fitness is at one or two sessions a week and climbing slowly. Sleep is not getting fixed this year and I've stopped pretending it might.

What changed isn't my behaviour. It's that the deficit is a line item in the FIRE plan now instead of a mood. It has a name, a rough price, and a partner who has heard me say it. We already modelled what the baby would cost the plan before she arrived, about six months on the FI date, and planning it beat panicking about it by a distance. This is the same trick pointed at a different asset.

Some people genuinely don't mind the ten-year round-the-clock grind, and that's fine. Some want a normal schedule for 25 years with a tighter budget and their health intact throughout, and that's equally fine. The trade-offs are yours to pick. They're just not yours to skip.

So say the one you're making out loud, to someone who'll remember you said it. That's the whole method. I'm bad at it, I'm doing it anyway, and next September I'd like the football to go better than this one did.