A small study suggested larger oxygenation responses during higher-intensity exercise, but its highlighted regional and connectivity comparisons did not survive correction for multiple testing. It did not establish that harder exercise produced superior cognitive recovery.
Gao and colleagues randomized 20 abstinent methamphetamine-dependent men to moderate- or high-intensity cycling. Each session included a 25-minute main exercise stage within 35 minutes of activity. Functional near-infrared spectroscopy measured prefrontal hemodynamic changes during exercise. One participant per group was excluded for artifacts, leaving 18 in the analyses.
The overall prefrontal oxygenated-hemoglobin comparison had p = 0.063. For left dorsolateral prefrontal cortex, the uncorrected p value was 0.011 but the corrected value was 0.066. The orbital-frontal to left-dorsolateral connectivity comparison changed from uncorrected p = 0.040 to corrected p = 0.20. None of these corrected results established conventional statistical significance. A favorable direction is not the same as a confirmed between-group effect.
fNIRS measures changes in hemoglobin-related signals rather than direct neuronal repair, methamphetamine concentration or executive ability. The study’s measurements occurred during exercise, not during a demonstration of improved daily functioning afterward. Small samples, motion-related exclusions and limited intensity records constrain interpretation. All participants were men in rehabilitation and had been abstinent for at least three months. These findings justify larger mechanistic studies, but not a general recommendation that high intensity is superior for every patient. The appropriate account reports the correction, the uncertainty and the measured physiological endpoint rather than converting an exploratory trend into established treatment efficacy.
See why statistical comparisons determine the strength of a mechanistic claim.