Three sessions a week. For ten years.

Why "3× a week"

Most public-health and sports-medicine guidance converges on roughly 150 minutes of moderate aerobic activity a week, often divided into three 50-minute sessions or four 35-minute sessions. The number is not magic. It's the floor at which measurable cardiovascular and metabolic benefits show up consistently in the literature.

For most adults, three sessions a week, sustained for a decade, is the boundary between "sedentary trajectory" and "moderately active trajectory." Past that point, more is better up to about 5–6 sessions a week, where additional minutes start to give diminishing returns for general health outcomes.

The decade-difference, in face terms

Compared to a sedentary peer of the same chronological age, a 3×/week-consistent person at year ten typically presents:

• Better skin tone — circulation drives perfusion which drives color. Pale, sallow under-eye is much rarer.
• Tighter jaw and neck — postural muscle support transfers visibly into the face's resting line.
• Faster recovery from minor illness — colds clear faster; the face does not hold the "hollowed out" look as long.
• Lower visible inflammation — under-eye puffiness, ruddy patches, slower minor-injury healing — all reduced.

None of this is dramatic. The 3×/week person doesn't look ten years younger; they look their age, without the additional aging that sedentary life adds.

The hidden compounding

Exercise 3×/week interacts with sleep, hydration, and stress in ways that produce more facial benefit than the exercise alone would explain. People who exercise consistently sleep better (faster onset, deeper slow-wave). Better sleep produces better skin repair. Repaired skin handles UV better. UV handled better produces less photoaging. Less photoaging makes the face age slower at the same chronological rate.

This stacking effect is part of why exercise-and-face research is hard to isolate cleanly. The exercise causes the better sleep that causes the better skin. Saying "exercise improves skin elasticity" understates and overstates simultaneously.

If you exercise 3×/week now

The mirror at year five will probably look continuous with peers — the early-stage benefits are real but small. By year ten the gap has widened. By year twenty it is the kind of difference strangers will guess about you (your active stranger looks "in their forties" when they're actually in their fifties; the sedentary stranger reads as their age or slightly older).

Precog's portrait at +10y for a 3×/week consistent person is the face this trajectory builds. The point is not to stress you about needing to do more — three is enough. The point is to make the invisible compounding visible enough that on a slow week you remember why the floor matters.

If you don't exercise yet

The most common mistake is starting with an ambitious plan. Six sessions a week, lasting 11 days, then nothing for 4 months. The math: 0.

Three sessions a week, sustained for 10 years, beats six sessions a week sustained for 6 weeks by a multiplier we don't even have good math for. Frequency × duration × consistency.

Start at 3. If it sticks for a quarter, you can negotiate up. If it doesn't, the question is what made it not stick — usually scheduling, not motivation.