Cited by 269Cardiovascular and exercise physiologySports Performance and TrainingPhysical Activity and Health

The DOI matches its Crossref record; 32 of the 32 references it cites were found in a registry or an index; none of the 10 sources its claims cite is checked for support yet.

&OV0312;O2 reserve and the minimal intensity for improving cardiorespiratory fitness

Open access
SWAIN, DAVID P., FRANKLIN, BARRY A.·2002·Medicine & Science in Sports & Exercise

Abstract

PURPOSE: The American College of Sports Medicine has stated that aerobic training needs to occur at a minimum threshold intensity of 50% VO(2max) for most healthy adults and at 40% VO(2max) for those with a very low initial fitness. Recently, the concept of VO(2) reserve (%VO(2R), i.e., a percentage of the difference between maximum and resting VO(2)) has been introduced for prescribing exercise intensity. This analysis was designed to determine the threshold intensity for improving cardiorespiratory fitness expressed as %VO(2R) units. METHODS: Previous studies in healthy subjects (N = 18) that evaluated the results of training at low-to-moderate intensities (i.e., < or = 60% VO(2max)) were identified. The original studies described the intensity of exercise variously as %VO(2max), %HRR, %HR(max), or as a specific HR value. In each case, the intensity was translated into %VO(2R) units. RESULTS: Exercise training intensities below approximately 45% VO(2R) were consistently ineffective at increasing VO(2max) in studies that used subjects with mean initial VO(2max) values > 40 mL x min(-1) x kg(-1). In studies using subjects with mean initial VO(2max) values < 40 mL x min(-1) x kg(-1), no intensity was found to be ineffective. For this latter group of subjects, the lowest intensities examined were approximately 30% VO(2R). CONCLUSION: Although evidence for a threshold intensity was not strong, this analysis of training studies supports the use of 45% VO(2R) as a minimal effective training intensity for higher fit subjects and 30% VO(2R) for lower fit subjects.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This analysis converted low-to-moderate training intensities from 18 prior studies into %VO2 reserve units to estimate the minimal intensity needed to raise VO2max. It supports roughly 45% VO2R for higher-fit subjects and roughly 30% VO2R for lower-fit subjects, while noting that evidence for a strict threshold is not strong.

Key findings

  • For groups with mean initial VO2max above 40 mL·min⁻¹·kg⁻¹, training below about 45% VO2R was consistently ineffective at increasing VO2max; intensities above this level generally produced improvements.
  • For groups with mean initial VO2max below 40 mL·min⁻¹·kg⁻¹, every examined training intensity produced significant VO2max gains, with the lowest intensities around 28–32% VO2R; the proposed minimal effective intensity was about 30% VO2R.
  • When translated back to %VO2max, 30% VO2R in lower-fit groups (mean VO2max 28.9 mL·min⁻¹·kg⁻¹) corresponded to about 38% VO2max, and 45% VO2R in higher-fit groups (mean VO2max 44.7 mL·min⁻¹·kg⁻¹) corresponded to about 49% VO2max, close to earlier ACSM guidelines of 40% and 50% VO2max.
  • Among 15 studies comparing two or more intensities, 5 found significantly greater VO2max improvement at the higher intensity and 8 showed a nonsignificant trend in the same direction.

Methods

  • The author identified 18 studies of healthy adults from ACSM position stands, a MEDLINE search, and cross-referenced bibliographies; inclusion required pre- and post-training VO2max measurement and at least one group training at approximately ≤60% VO2max.
  • Reported intensities were converted into %VO2R: %HRR was treated as equivalent to %VO2R; %VO2max was converted using gross exercise VO2 and an assumed resting VO2 of 3.5 mL·min⁻¹·kg⁻¹; %HRmax was converted with a formula derived from heart rate/VO2 data.
  • Training groups were collated by initial VO2max categories and translated intensity to examine whether a minimal effective intensity differed by fitness level.

Limitations

  • The paper states that translating prior intensities into %VO2R was indirect, especially for studies reporting specific heart rates or %HRmax, and that all conversions used group means rather than individual data; the findings are therefore preliminary.
  • The paper states that the higher-fit groups showing no improvement came from small studies with only 4–9 subjects per group and about 100 min·wk⁻¹ for 5–10 weeks, so low statistical power or insufficient training volume may explain the negative results.
  • The paper states that no threshold was apparent for lower-fit groups because intensities below 30% VO2R were not routinely tested; it also notes that between-study differences in duration, frequency, and program length make comparisons tenuous. Evident from the text, this is a narrative collation rather than a formal meta-analysis.

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Integrity signals

Registry

Crossref · 10.1097/00005768-200201000-00023

Cites

32 of 32 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

9 Own interpretation · 8 Own result · 3 Not checked yet · 3 No basis given · 2 No full text of the sources · 2 Own method · 1 Sources not found

  • It may state two separate claims as one. 13
  • Probably not a substantial claim. 4
  • The quote only partly states this claim. 1
15 of 15
  • The authors state this as an assumption.

    Heart rate reserve values are equivalent to oxygen consumption reserve values.

    “Some studies reported the intensity as %HRR (2,3,12,14,24,30), and these were assumed to provide equivalent values in %V ˙O2 R units (33,34).”
  • The authors state this as an assumption.

    The average resting oxygen consumption of the subjects was 3.5 mL/min/kg.

    “in which the value 3.5 mL•min Ϫ1 •kg Ϫ1 was assumed to be the average resting V ˙O2 of the subjects.”
2 of 2

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Citations

Cites

Show all 30 references

Research works printed but not linked: 11

  1. 1990, Med Sci Sports Exerc, 22, 265
  2. Burke, 1975, Res Quart, 46, 31
  3. Davies, 1971, Int Z Angew Physiol, 29, 299
  4. Devries, 1971, Geriatrics, 26, 94
  5. Edwards, 1974, Med Sci Sports, 6, 14
  6. Faria, 1970, Res Q, 41, 44
  7. Gaesser, 1984, Med Sci Sports Exerc, 16, 269
  8. Hagberg, 1986, Acta Med Scand, 711, 131
  9. Karvonen, 1957, Ann Med Exp Biol Fenn, 35, 307
  10. Pollock, 1998, Med Sci Sports Exerc, 30, 975
  11. Swain, 1994, Med Sci Sports Exerc, 26, 112

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Metadata

Authors
SWAIN, D. P., & FRANKLIN, B. A.
Affiliations
Beaumont Health (US)
Venue
Medicine & Science in Sports & Exercise
Published
2002-01
Volume
34
Issue
1
Pages
152-157
ISSN
0195-9131 (ISSN-L)
OpenAlex
W2027535482
Cited by
269
References
30
Citations by year
2026: 15 · 2025: 14 · 2024: 13 · 2023: 15 · 2022: 8 · 2021: 13 · 2020: 17 · 2019: 12 · 2018: 14 · 2017: 14 · 2016: 9 · 2015: 9 · 2014: 7 · 2013: 14 · 2012: 17
FWCI
16.69
Type
journal article
Language
en
Open access
Locations
  • Medicine & Science in Sports & Exercise (publishedVersion)
  • PubMed (publishedVersion)
  • ODU Digital Commons (Old Dominion University) (submittedVersion)
Topics
  • Health Sciences › Medicine › Physiology (medical) › Cardiovascular and exercise physiology
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Health Sciences › Medicine › Public Health, Environmental and Occupational Health › Physical Activity and Health
Keywords
exercise intensity thresholds, cardiorespiratory fitness, aerobic exercise, VO2max, exercise prescription, low-intensity training, heart rate reserve
MeSH terms
Adaptation, Physiological, Adolescent, Adult, Aged, Aged, 80 and over, Female, Heart Rate, Humans, Male, Middle Aged, Oxygen Consumption, Physical Education and Training, Physical Fitness, Anaerobic Threshold, Program Evaluation, Exercise

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