Why Some People Don’t Lose Brain Function as They Age 🧠

Key points — brain aging and what preserves cognition

• Cognitive decline is not inevitable. Longitudinal studies show many people maintain stable cognitive function from their 50s into their 70s–80s. Population averages decline mainly because a subset of people lose function and pull the mean down.
• The term “superager” refers to someone who, in their 80s, performs cognitively at the same level they did in their 50s. Superagers tend to share common, non‑extraordinary behaviors rather than unusual genetics.

“Superager”: an individual who maintains in their 80s the same cognitive performance they had in their 50s.

Features associated with preserved cognitive function (characteristics of superagers)

• Avoidance of major metabolic diseases (e.g., diabetes, cardiovascular disease)
• Regular physical activity
• Social connection and engagement
• Good, consistent sleep habits
• Low-to-moderate alcohol use
• Psychological factors summarized as the three R’s:
  • Reserve
  • Resilience
  • Resolve (persistent, consistent engagement in healthy behaviors)

Exercise and brain structure/function — discoveries and trials

• Any increase in physical activity helps cognition. In sedentary older adults, brisk walking (~40 minutes, three times per week) produced measurable increases in hippocampal volume and memory function.
• Intensity matters. A randomized trial comparing low‑intensity (walking), moderate (jogging), and high‑intensity interval training (HIIT) found larger hippocampal structural and functional gains in the HIIT arm.
• In that study, VO2max improvements were similar in the jogging and HIIT groups, indicating the hippocampal benefits of HIIT were not explained solely by aerobic-fitness gains.
• The hippocampal improvements in the HIIT group continued across the 6‑month trial and were still detectable at a 5‑year follow‑up, even though participants had not continued the protocol.

Norwegian 4×4 HIIT protocol (used in the trial)

• Work intervals: 4 minutes at 85–95% of maximum heart rate
• Recovery intervals: ~3 minutes between work intervals
• Four repeats (4×4), plus warm‑up and cool‑down → total session ≈ 40–45 minutes
• Frequency in the trial: 3 sessions per week for 6 months

Methodologies described

• Seattle Longitudinal Study:
  • Cohort study begun in the 1950s.
  • Repeatedly tested the same participants approximately every 7 years and added new age waves.
  • Allowed observation of within‑person cognitive trajectories across decades rather than relying on cross‑sectional age comparisons.
• Randomized controlled exercise trial:
  • Compared intensity levels (walking vs. jogging vs. Norwegian 4×4 HIIT).
  • Protocol: 3 sessions per week for 6 months, with long‑term follow‑up.

Researchers and sources featured

• K. Warner Schaie — Seattle Longitudinal Study
• John J. Ratey — book “Spark” (exercise and the brain)
• An Australian randomized trial using the Norwegian 4×4 HIIT protocol (study group not named)
• Term/source: “superager” (contemporary label for people who maintain cognition)