Inter-Individual Responses of Maximal Oxygen Uptake to Exercise Training: A Critical Review.
Level 5 - mechanism / opinion, no new human data
Critical narrative review and methodological re-analysis of published studies
PubMed 28097487 · doi:10.1007/s40279-017-0680-8
What was done
The authors conducted a critical review of literature evaluating inter-individual variation in maximal oxygen uptake (VO2 max) changes following exercise training. They searched bibliographic databases and identified six studies published prior to the HEalth, RIsk factors, exercise Training And GEnetics (HERITAGE) Family Study, reviewed over 180 HERITAGE-derived publications, and evaluated twin studies. The authors assessed the presence of non-training comparator groups to determine whether standard deviations of change scores exceeded random within-subject variation, and they re-analyzed data from the single pre-HERITAGE study that included a comparator group.
What was found
Only one of the six pre-HERITAGE studies included a comparator group. Re-analysis of this study showed that the standard deviation of change was larger in the comparator group (±5.6 mL/kg/min) than in the intervention group (±3.7 mL/kg/min), demonstrating no true inter-individual variation in VO2 max response beyond within-subject variability. None of the >180 HERITAGE Family Study publications included a comparator arm, relying instead on short-term test-retest reliability that did not match the intervention duration. Twin studies similarly lacked non-training control groups and utilized intraclass correlation analyses unadjusted for confounding factors like age, sex, and baseline fitness.
Why it matters
This review challenges the established narrative of distinct physiological responders and non-responders to exercise training, demonstrating that observed individual differences in VO2 max gains are largely artifacts of measurement error and random biological fluctuation in the absence of control groups.
Limits
The quantitative re-analysis was limited to a single historical study because all other identified literature lacked a non-training control arm. The abstract does not provide systematic review metrics, search strings, quality assessment scores, or total human sample sizes across the reviewed literature.
Cited by
- context Approximately 40% of people do not see a measurable increase in VO2 max after engaging in 2.5 hours per week of guideline-based moderate-intensity exercise for several months.