Daily incidental physical activity—especially vigorous or moderate—shows steep, dose-responsive reductions in cardiovascular events and mortality; 1 minute vigorous ≈ 3 minutes moderate.

Background

Most middle-aged and older adults do not perform structured exercise. Incidental physical activity (IPA)—unplanned activity during daily living—may circumvent barriers to exercise. Evidence guiding dose–response and intensity “equivalence” for IPA has been lacking, particularly using device-based measures.

Patients

• UK Biobank accelerometry sub-study nonexercisers: n=24,139 (56.2% women), mean age 61.9±7.6 years.
• Analytic samples: MACE n=22,107 (events=908); CVD mortality n=22,174 (events=223); all-cause mortality n=24,139 (events=1,071).
• Predominantly White (96.1%); wore wrist accelerometers for 7 days (≥3 valid days including ≥1 weekend day).
• Excluded: prevalent major CVD for MACE/CVD mortality analyses; events in first year of follow-up; insufficient wear; inability to walk; missing covariates.

Intervention

Exposure to device-measured incidental physical activity by intensity using a validated two-stage machine-learning classifier:

• Vigorous IPA (VIPA): ≥6 METs (minutes/day).
• Moderate IPA (MIPA): 3–6 METs (minutes/day).
• Light IPA (LIPA): 2–3 METs (minutes/day).
• Total IPA volume: PAEE (kJ·kg⁻¹·day⁻¹).

Control

• Reference exposure: 0 min/day for VIPA and MIPA; lowest observed LIPA (33.2 min/day); minimum PAEE (7.73 kJ·kg⁻¹·day⁻¹).

Outcome

• Primary: Major adverse cardiovascular events (MACE: nonfatal MI, stroke, heart failure) and CVD death.
• Secondary: All-cause mortality.

Study Design

• Prospective cohort; UK Biobank accelerometry (2013–2015) with national linkage for outcomes to 2022.
• Competing-risk Fine–Gray subdistribution hazard models; adjusted for demographics, behaviors, sleep, sedentary time, medications, prior cancer, and family history; intensity models mutually adjusted for other intensity PAEE.

Level of Evidence

• Oxford CEBM Level 2b (individual prospective cohort study).

Follow up period

• Mean 7.9 years (≈171,000 person-years per cardiovascular outcome set).

Results

• Total IPA volume: L-shaped association with nadir ≈35–38 kJ·kg⁻¹·day⁻¹.
  • MACE HR 0.49 (95% CI 0.39–0.61).
  • CVD mortality HR 0.33 (95% CI 0.22–0.52).
  • All-cause mortality HR 0.31 (95% CI 0.25–0.38).
• Intensity-specific dose–response:
  • VIPA: Any amount lowered risk; near-plateau ≈14 min/day.
    • Median VIPA 4.6 min/day associated with:
      • Primary: MACE HR 0.75 (95% CI 0.65–0.87); CVD mortality HR 0.62 (95% CI 0.46–0.83).
      • Secondary: All-cause mortality HR 0.76 (95% CI 0.67–0.87).
  • MIPA: Steep inverse gradient; nadir ≈34–50 min/day then plateau/inversion.
    • Median MIPA 23.8 min/day associated with:
      • Primary: MACE HR 0.60 (95% CI 0.47–0.76); CVD mortality HR 0.50 (95% CI 0.31–0.80).
      • Secondary: All-cause mortality HR 0.53 (95% CI 0.43–0.65).
  • LIPA: Subtle inverse associations; statistically clearer only for CVD mortality >≈130 min/day.
• Intensity equivalence (per 1 minute VIPA):
  • MIPA: ≈2.8 minutes (MACE) to 3.4 minutes (CVD mortality).
  • LIPA: ≈48.5 minutes (MACE) to 34.7 minutes (CVD mortality).
• Approximate NNT over 7.9 years (based on overall sample baseline risks; interpret as estimates):
  • Baseline risks: MACE 4.11%; CVD mortality 1.01%; all-cause mortality 4.44%.
  • VIPA (median 4.6 min/day vs none):
    • MACE: ARR 1.03%; NNT ≈ 97.
    • CVD mortality: ARR 0.38%; NNT ≈ 262.
    • All-cause mortality: ARR 1.06%; NNT ≈ 94.
  • MIPA (median 23.8 min/day vs none):
    • MACE: ARR 1.64%; NNT ≈ 61.
    • CVD mortality: ARR 0.50%; NNT ≈ 199.
    • All-cause mortality: ARR 2.08%; NNT ≈ 48.

Limitations

• Observational design; residual confounding cannot be excluded despite extensive adjustment (E-values provided).
• UK Biobank participation bias (low response rate); generalizability may be limited, though exposure–outcome associations are typically robust.
• Lag between baseline self-reported nonexercise status and accelerometry (≈5.5 years), though repeat data suggest high stability.
• Intensity classification, while validated, is not perfect; LIPA effects modest and may be harder to detect.
• NNTs are approximations derived from hazard ratios and overall baseline risks, not randomized comparisons.

Funding

• Australian National Health and Medical Research Council investigator grant (APP 1194510). The funder had no role in design, analysis, or reporting.

Citation

Stamatakis E, Biswas RK, Koemel NA, Sabag A, Pulsford R, Atkin AJ, Stathi A, Cheng S, Thøgersen-Ntoumani C, Blodgett JM, Bauman A, Celis-Morales C, Hamer M, Gill JMR, Ahmadi MN. Dose Response of Incidental Physical Activity Against Cardiovascular Events and Mortality. Circulation. 2025;151:1063–1075. DOI: 10.1161/CIRCULATIONAHA.124.072253.