VO2 max rarely appears on a standard cardiac workup. This is a significant gap. I see its consequences regularly in patients who have been reassured by normal stress tests while their true cardiorespiratory fitness tells a different story.
Case:
58 year old male retired engineer. Self-referred after reading about VO2 max and longevity. He had seen his cardiologist six months prior following chest tightness during a golf game. Stress test was normal. He was told his heart was fine and sent home. He exercised “regularly” (30 minute walks three times weekly) and considered himself healthy. He had gained 22 pounds over the past decade and described increasingly poor energy and concentration.
Labs:
Estimated VO2 max: 24 mL/kg/min (bottom 10th percentile for age, high mortality risk)
Resting heart rate: 78 bpm (elevated, poor cardiovascular fitness indicator)
Grip strength: 28 kg dominant (below age-sex threshold, sarcopenia likely)
Waist-to-height ratio: 0.58 (above 0.5 threshold, significant visceral fat)
Fasting insulin: 16 uIU/mL (insulin resistant, standard glucose was normal)
6 min walk test: 410 meters (below 500m threshold for age, clinically significant)
His cardiac structure was normal — his cardiologist was not wrong. But his cardiorespiratory fitness was in the bottom percentile for his age, a condition that carries a higher mortality risk than most diagnosed cardiac conditions. His VO2 max of 24 mL/kg/min put him at approximately 4x mortality risk of a man in the top quartile of fitness. This was not detected because VO2 max is not typically part of a standard cardiac evaluation. His chest tightness during golf was likely demand ischemia from severe deconditioning, not structural coronary disease.
What I recommended:
Established a true Zone 2 heart rate range (97-113 bpm for him) — he had been walking at 85 bpm, well below the aerobic training threshold, which explains why 30 minute walks three times weekly had produced no fitness improvement in years.
Increased Zone 2 duration progressively: weeks 1-2 at 30 minutes, weeks 5-8 at 50 minutes — allowing musculoskeletal adaptation to precede cardiovascular demand.
Added twice weekly resistance training focused on lower body compound movements — to address grip strength, sarcopenia (muscle loss), and the IGF-1/irisin pathway for concurrent brain health benefit.
Referred to a registered dietitian for protein optimization — at 58, his protein intake of approximately 60g/day was insufficient for muscle protein synthesis, perpetuating his sarcopenia.
The Outcome:
At 6 months, his estimated VO2 max had risen from 24 to 33 mL/kg/min — moving him from the 10th to the 42nd percentile for his age. Resting heart rate dropped from 78 to 65 bpm. He lost 15 pounds. Fasting insulin normalized to 7 uIU/mL. Grip strength increased from 28 to 38 kg. He described his cognitive clarity and energy as “better than my 40s.” His cardiologist, at his 6 month follow up, noted the improvement and asked what he had done differently.
From the Neurologist:
A normal stress test does not tell you that someone is fit. It tells you their heart does not have obstructed coronary vessels under standardized moderate exercise challenge. VO2 max tells you something different: how effectively their entire oxygen delivery system (heart, lungs, vasculature, mitochondria) functions under demand. For brain health specifically, VO2 max is the variable I watch most closely. It predicts hippocampal volume, processing speed, and dementia risk better than almost any biomarker available.
Call to Action:
If you had a “normal” cardiac workup but feel deconditioned, ask for a VO2 max test or at minimum a 6 minute walk test. A normal stress test and a healthy VO2 max are not the same thing.
Disclaimer: The content published in The Brain Capsule is for informational and educational purposes only. It is not intended to substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider before making any changes to your health, diet, or wellness routine. The views expressed are based on current research and are subject to change as new evidence emerges.