Rai et al. (2026) — a digital mindfulness therapeutic for high-intensity exercise
A Farb-group randomized trial (Rai first author, Farb senior) testing whether a smartphone mindfulness therapeutic can improve how people perform and feel during high-intensity exercise (HIE). Seventy undergraduates (M age 26.5, 58.5% female) trained for three weeks with either the research predecessor of AmDTx — a Mobio Interactive app delivering guided meditation, body scans, open-monitoring practice and didactic content — or an active control: a cognitive-training app built on the 2048 puzzle game, matched for daily engagement, mood/stress check-ins and a camera-based heart-rate snapshot. Both arms are active, which the authors call an “activated RCT.” The endurance outcome was time to voluntary exhaustion (TVE) on a Maximal Athletic Performance (MAP) stationary-bike test, with affective wellbeing sampled every two minutes during the test.
What the study actually shows
The paper reports four results that need to be held apart, because the headline (“mindfulness improved exercise performance”) is the weakest of them and the most interesting finding is a null.
- The manipulation check worked. The app raised MAIA interoceptive awareness more than the control (β=1.83, p=0.044). This is what licenses calling the app “mindfulness training” at all, and it replicates the same DTx’s earlier effect on subjective wellbeing (Walsh et al. 2019).
- Performance moved, barely. Mindfulness produced a small significant advantage on TVE (β=0.21, p=0.041), concentrated in the women, who began with lower endurance.
- Wellbeing did not move (β=−0.55, p=0.083). The affective-valence hypothesis — the paper’s own motivating idea, that mindfulness makes HIE feel better and so gets repeated — failed.
- Nothing mediated the performance gain. Not one preregistered mediator showed a group×time effect, so the mediation analysis could not proceed past its first step. Whatever produced the modest TVE benefit, the study could not attribute it to interoception, mindfulness, attentional focus, mental toughness, or mental/physical health.
The load-bearing wrinkle: awareness rose, performance rose, and they did not co-vary
The intervention raised MAIA and raised TVE, which invites the natural reading that heightened interoceptive awareness drove the performance gain. The correlations refuse it. At the person level MAIA was uncorrelated with both performance measures — MAIA↔TVE r=−0.02 (ns), MAIA↔performance factor r=0.05 (ns) — while the factor that did track performance was effort and distress tolerance (r=0.38 with the performance factor, r=0.25 with raw TVE). MAIA’s strong correlate was instead attitude (r=0.74), inside the self-report cluster.
(A note on the source: the results text on p.342 reads “significant positive correlations between MAIA, r=0.74” with the second variable dropped; Fig. 3 makes clear the r=0.74 partner is attitude, not TVE, and that both MAIA↔performance cells are non-significant. The figure values are authoritative here.)
So the causal chain the title gestures at is broken in the middle. Training raised interoceptive awareness; training raised endurance; the two increases were unrelated across individuals; and the EFA moved only the distress-tolerance factor, not the awareness factor. The most defensible reading — and roughly the one the discussion reaches — is that mindfulness helped people tolerate the effort and discomfort of HIE, an indirect distress-tolerance route, with interoceptive awareness a correlate of the training rather than the mechanism of the benefit. See interoceptive-exposure: HIE is itself a naturally occurring exposure to aversive bodily sensation, and tolerance of that sensation is the plausible lever.
Why this belongs to a pattern, not a one-off
This is the third Farb-group trial in the wiki to compare a mindfulness/interoceptive arm against a serious active comparator and find the nominated interoceptive mechanism not carrying the result:
- Farb et al. (2022): MBCT vs Well-Being CT — equal relapse, shared prefrontal biomarker, no mindfulness-specific effect.
- Eusebio et al. (2022): interoceptive vs movement yoga — equal MAIA and symptom change, mechanism visible only as attentional transfer.
- Rai et al. (2026): mindfulness vs cognitive training — MAIA rose but did not mediate or even correlate with the modest performance gain.
The recurring shape (see norman-farb, and the central caveat on mindfulness-interoceptive-training): when this group tests its own interoceptive account against an active control rather than a waitlist, self-reported interoception moves as advertised, the nominated outcome moves weakly or not at all, and the interoceptive mechanism is not demonstrated. Rai et al. is the cleanest of the three on the mechanism point, because it measured a mediator and reported its failure plainly.
For the reader deciding what to take away
The honest summary is the one the limitations section supports: a short, scalable, digitally delivered mindfulness intervention produced a small endurance benefit in an activated RCT with an unequal randomization and no passive control, and that benefit is not shown to work through interoception — the interoceptive-awareness increase was real but inert with respect to performance, and distress tolerance is the better candidate. As a datum for is-more-interoceptive-awareness-better, it is a case where more self-reported interoceptive awareness was induced and bought nothing measurable on the behavioural outcome. As a datum for does-mindfulness-enhance-interoceptive-accuracy, it is silent: no accuracy task was administered, so the MAIA rise is a change in sensibility only (see interoceptive-taxonomy).