560-610 minutes of exercise a week needed for substantial heart benefits

Original Article ↗ Hacker News Discussion ↗

Required exercise time and benefits

  • New guideline (560–610 minutes/week of moderate–vigorous activity) is contrasted with prior ~150 minutes/week.
  • Study claims ~8–9% cardiovascular risk reduction at 150 minutes vs >30% at ~10 hours/week.
  • Some note other umbrella reviews suggesting much lower volumes (e.g., 15 MET-hours) already capture most benefits, making this result seem extreme.
  • Several emphasize that smaller amounts still help; “substantial” is a definitional choice.

Feasibility and life constraints

  • Many find 9–10 hours/week unrealistic, especially for parents in dual‑income households.
  • Others argue it’s possible by:
    • Integrating exercise with childcare (stroller runs, playing, hikes).
    • Active commuting (cycling/walking to work).
    • Small, consistent habits (e.g., 30 seconds of daily calisthenics with kids, then expanding).
  • Tension between “people make excuses” and recognition that time, job, kids, climate, and housing strongly constrain options.

What counts as “moderate” or “vigorous”

  • Confusion over definitions: brisk walking is classified as “moderate,” vigorous is framed as sustained higher heart‑rate zones, distinct from all‑out HIIT.
  • Debate on whether chores, normal walking, and weight lifting count; some wearables show everyday walking barely raises heart rate.
  • Clarifications from the thread:
    • Walking, housework, gardening often counted as moderate.
    • Vigorous minutes may be weighted more (e.g., 2×) in guidelines.
    • HIIT is described as beyond “vigorous” and not sustainable at high weekly volumes.

Health tradeoffs and human limits

  • Some argue 10 hours/week is too big a time cost relative to added lifespan; others highlight healthspan and enjoyment (e.g., sports people love).
  • Concerns about joint wear and injuries; countered by claims that the body evolved for regular movement and most people under‑exercise.
  • Skepticism about very high volumes, especially in older ages and with potential overtraining.

Study design, bias, and uncertainty

  • Study is observational; several criticize causal language and note correlation vs causation issues.
  • Participant profile: average age ~57, mostly white. Some see this as “late in life” and not broadly representative.
  • Potential confounders: people who exercise more may also eat better, avoid smoking, have more time and money, and care more about health.
  • Use of accelerometer data:
    • May miss activities with little wrist movement (cycling, some strength work).
    • Raises questions about how “moderate/vigorous” minutes were inferred.
  • Exclusion of very high VO2max values as “implausible” and undercounting of certain activities are flagged as possible flaws.
  • Overall sentiment: mixed—some find the results motivating or validating; others view the headline as overreaching or discouraging.