Guidelines for Aerobic Exercise Training Intensity
New research recommends more individualized training guidelines.
A 2025 review published in Sports Medicine challenges traditional aerobic exercise guidelines that rely on fixed percentages of peak heart rate or VO₂ max. Researchers from Hasselt University in Diepenbeek, Belgium, found that prescribing training intensity using individual thresholds such as ventilatory threshold (VT1/VT2) or lactate threshold (LT) leads to more consistent physiological responses and greater improvements in cardiovascular fitness and metabolic health. Across 15 cross-sectional studies and a meta-analysis of 42 trials, threshold-based training outperformed fixed-percentage methods in boosting VO₂ max and reducing inter-individual variability in responses like heart rate and blood lactate.
Study authors urge moving beyond “one-size-fits-all” prescriptions and embrace more personalized approaches. While threshold testing can be lab-based, simpler methods like using perceived exertion (RPE) or talk tests can approximate thresholds effectively in most settings. Tailoring intensity to each person’s physiology leads to better results, especially for health-focused training.
As a reminder, when using a 1-10 Borg’s scale of perceived exertion (RPE), an RPE of 3-4 (moderate – can talk but not sing) correlates with VT1 and an RPE of 6-7 (hard to very hard – talking becomes difficult) correlates to VT2.
Shirley Eichenberger-Archer, JD, MA
Shirley Eichenberger-Archer, JD, MA, is an internationally acknowledged integrative health and mindfulness specialist, best-selling author of 16 fitness and wellness books translated into multiple languages and sold worldwide, award-winning health journalist, contributing editor to Fitness Journal, media spokesperson, and IDEA's 2008 Fitness Instructor of the Year. She's a 25-year industry veteran and former health and fitness educator at the Stanford Prevention Research Center, who has served on multiple industry committees and co-authored trade books and manuals for ACE, ACSM and YMCA of the USA. She has appeared on TV worldwide and was a featured trainer on America's Next Top Model.
