Most people don't think about their health trajectory until something breaks. But your body has been sending signals since your 20s — you just haven't been told what to look for.
From age 20, you're already declining — just slowly
Muscle power starts dropping by roughly 8.3% per decade starting from your 20s (Bonnefoy et al., 1988). Nobody feels this at 25. By 55, it's the reason getting up off the floor takes a small negotiation with your knees.
Your mid-30s to 40s is when chronic conditions quietly start
Diabetes and high blood pressure typically first appear in this window, long before symptoms feel serious enough to act on. This is usually the exact age range where people are busiest, sleeping least, and paying the least attention to a health screening.
After 65, decline doesn't stay linear — it steepens
Between 65 and 89, knee power — the strength you actually use to climb stairs or rise from a chair — declines at roughly 3.5% per year, more than double the 1–2% annual drop in general strength (Skelton et al., 1994). This is precisely why strength and balance training can't wait until it becomes obviously necessary. By the time it's obvious, you're already losing ground faster.
This is where the healthspan gap comes from
We've written before about the "morbidity gap" in Singapore — despite some of the world's highest life expectancy, the average person still spends 11.2 years in poor health. These numbers are why. It isn't one dramatic event. It's decades of gentle, unaddressed decline compounding quietly until it isn't gentle anymore.
Know your numbers before they become symptoms
You don't need to panic about any of this. You need to know it — early enough that the trend is still gentle, not after it's already steep.