Evidenced Health

Physical Activity and Fitness Hub

5 min read

Navigator for the aerobic-activity and fitness clusters — how much movement and fitness move mortality, whether raising them helps, and whether the energy spent on exercise is offset by compensation. The strength, resistance-training, muscle, and falls side moved to Musculoskeletal Health and Physical Function Hub. Nucleus: Cardiorespiratory Fitness and Mortality.

Aerobic activity and sedentary time — dose and mortality

  • Physical Activity Dose and Mortality — the objective-measured dose-response (accelerometry removes the self-report plateau; the steepest gains are at the least-active end), the step-count targets (age-varying plateau ~6-8k older / 8-10k younger), and whether ~60-75 min/day of activity offsets the mortality risk of prolonged sitting (it does)
  • Sedentary Behaviour and Chronic Disease Risk — the dedicated sedentary anchor (Patterson 2018 gold dose-response MA): total sitting vs TV viewing as two exposures, per-outcome accelerating-harm knees (~8h sitting / ~3.5h TV for all-cause; PA-adjusted), and incident T2D — TV->T2D the strongest association (1.09/h, 29% PAF), most caveated by reverse causation and dietary mediation
  • Wearable Activity Trackers and Physical Activity — the adherence/behaviour-change lever for reaching the dose (not a new dose fact): a consumer tracker adds ~627 steps/day (95% CI 417-862, I2=3%, GRADE low) short-term, but durability is unproven (the 2 trials >=12mo showed lower adherence) and the outcome is a surrogate; ranks as a small adherence aid, best paired with human contact, most useful for the near-inactive (Brickwood 2019 MA, 28 RCTs)
  • The Physical Activity Paradox — the domain caveat on the dose page: high occupational (work) PA associates with higher mortality in men (Coenen, HR 1.18), opposite to leisure/total PA — so physically demanding work does not substitute for leisure exercise on the mortality outcome (LOW confidence; observational, healthy-worker selection; opens the occupation cluster)
  • Night Shift Work and Breast Cancer — the occupation cluster’s circadian channel, and a well-powered NULL: pooled across 10 prospective studies (1.4M women) night shift work shows no meaningful effect on breast cancer (RR 0.99, 0.95-1.03), overturning a case-control-driven prior and the IARC 2A probable carcinogen reading (MEDIUM confidence; a symmetric-standards counterweight)

Cardiorespiratory fitness — marker and lever

  • Cardiorespiratory Fitness and Mortality — how strongly VO2max predicts mortality, whether there is a target, and whether raising it helps
  • Measuring and Raising Cardiorespiratory Fitness — how to measure your fitness, how much exercise raises it (HIIT vs MICT — HIIT modestly ahead, time-efficiency the real draw), and whether raising it actually lowers risk
  • HIIT vs Continuous Training for Type 2 Diabetes — the modality choice in the T2D stratum: HIIT beats MICT on VO2peak (moderate certainty) but the HbA1c/weight edge is low-certainty and contested (a prior MA found no modality difference); HbA1c is a surrogate, no hard outcomes measured
  • Affective Response to High-Intensity Interval Exercise — does HIIT feel worse? A gold MA (Niven) finds higher-intensity work is felt as less pleasant in-task than moderate continuous exercise, with no post-exercise rebound — but the aversion tracks intensity, not the interval format, and the step from worse feeling to worse adherence is unproven
  • Ketogenic Diet and Endurance Performance — a gold MA finds keto (K-LCHF) does not improve VO2max, time-to-exhaustion, HRmax or RPE in endurance athletes despite a large fat-oxidation shift (RER) — a surrogate-vs-outcome disconnect; the fat-adaptation performance belief is unsupported
  • Exercise Snacks and Cardiometabolic Health — brief (1-2 min) vigorous bouts spread across the day raise VO2max and lower LDL-C, concentrated in the inactive; body composition does not move; evidence is surrogate-only over <=12 weeks, so a floor-above-nothing entry lever, not a demonstrated substitute for the full activity dose (the authors call it a complement, not a replacement)

The economics of exertion

  • Exercise Energy Compensation — whether exercise expenditure is offset by reduced non-exercise activity or increased intake, and whether higher intensity worsens the offset
  • Exercise vs Caloric Restriction for Visceral Fat — at a matched weekly energy deficit, exercise reduces visceral fat more than diet (dose-dependent; diet’s slope flat) — the exercise-vs-diet lever for the metabolically-active depot
  • Exercise Modality for Body Composition in Obesity — the head-to-head NMA ranking (aerobic vs resistance vs combined) for adults with obesity: combined training ranks top, resistance-only worst, and exercise alone barely moves weight (~1 kg) whatever the modality — fine rankings rest on non-significant differences, CRF on zero
  • FatMax Training for Body Composition and Cardiometabolic Health — “fat-burning zone” training is individualised light-to-moderate aerobic, not a distinct modality; it beats no-exercise on body composition and glycaemia but has no active comparator to show it beats ordinary moderate aerobic, and its “optimal 2446 min” apex is an unreplicated observational U-curve, not a target

Physical activity and chronic kidney disease

  • Chronic Kidney Disease and Modifiable Exposures — PA is the WEAKEST of the three CKD-prevention levers (Seidu MA: most-vs-least-active RR 0.91, GRADE very-low, all 12 cohorts serious ROB, 95% prediction interval 0.75-1.09 crosses 1); healthy-user self-selection + reverse causation uncorrected, and PA’s mechanism routes largely through the obesity/glycaemia/BP channels. See the nucleus for the full 3-lever ranking

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