Bryan Johnson measures almost everything about his body. Blood, sleep, muscle, inflammation, the pace of his own ageing. The most measured man alive.
And still, the one system he breathes for eight hours a night mostly goes unaudited: the room itself. You can optimise the biology all you like, but it lives inside a building, and the building has a say. So here are three things to check in your home today. No equipment, no cost, no specialist. Most people never check a single one of them.
One. Artificial grass
What to check. Any synthetic lawn where children or pets play, and the rubber crumb worked into it.
How to check today. On a warm day, place your palm flat on it. If it is dramatically hotter than the surfaces around it, it is actively releasing compounds into the air just above it. Note the product name and search it alongside the phrase "forever chemicals."
When to call a professional. When you want the infill lab-tested, or you are planning to replace it and need alternatives that prove they are clean.
Two. Off-gassing from anything new
What to check. Anything painted, floored or furnished in the last twelve months.
How to check today. Close the room for two hours, then walk back in. If you can smell "new," you are breathing volatile compounds. Check the tins and labels for "low VOC" or "zero VOC," and if it does not say so, assume it is not.
When to call a professional. When the smell is still there after six months, when anyone in the house has unexplained headaches or fatigue, or when you are about to renovate and want it done right the first time.
Three. The two things you consume most, water and air
What to check. Your tap water and your bedroom air.
How to check today. Search your postcode alongside "water quality report" and read your supplier's own figures. For the air, check your bedroom tonight. Can you smell anything? Is there condensation on the windows in the morning? Both are signals that your air needs attention.
When to call a professional. When the water report shows anything close to legal limits, when you find damp or a musty smell, or when you want continuous monitoring instead of a one-off guess.
The single sentence
Three checks, one afternoon. Most people never run them, then wonder why the healthiest version of themselves stops at the front door.
Want the full picture of what your home is doing to your biology? A free MAVI Snapshot scores your actual address in about two minutes and tells you where to start.