PMID 34337406

Research
All papers

Promoting Exercise and Healthy Diet Among Primary Care Patients: Feasibility, Preliminary Outcomes, and Lessons Learned From a Pilot Trial With High Intensity Interval Exercise

Smith-Ryan AE, Weaver MA, Viera AJ, Weinberger M, Blue MNM, Hirsch KR

Question

Is a primary-care-linked home program combining HIIT and dietary support feasible for patients with cardiovascular risk factors?

Summary

This small primary-care pilot tested a 12-week home lifestyle program combining HIIT and a daily meal replacement in adults with cardiovascular risk factors. Some completers improved fitness or risk markers, and no adverse events were reported, but dropout was high, adherence tracking was difficult, and there was no control group.

Methodology

  • Primary care patients with at least one cardiovascular risk factor
  • 16 participants.
  • Home high-intensity exercise.
  • Work intervals: 1 minute.
  • Recovery: 1 minute active or passive rest.
  • Intensity: 75-95% maximum heart rate.
  • About 25 minutes with warm-up.
  • 2 sessions/week required; 3 encouraged.
  • 12 weeks.
  • Single-arm pilot feasibility study
  • Feasibility, Cardiorespiratory fitness, Cardiometabolic risk, and Safety were tracked.

Outcomes

Retention

Retention and initiation were major feasibility issues.

10/16 returned post; 4 did not initiate training and 2 dropped out in the first 2 weeks.

Safety concern

VO2peak

Most completers improved cardiorespiratory fitness.

VO2peak improved in 80% of completers; mean change about +4.8 +/- 3.8 ml/kg/min in the extracted results.

Improved

Safety

No adverse events were reported.

Descriptive safety reporting.

No clear change

Insights

  • For app design, adherence capture must be easier than paper logs plus disconnected wearables.
  • A 10 x 1-minute interval structure is app-friendly, but high-risk users need clearance.
  • Cointerventions make it hard to attribute outcomes to HIIT alone.

Limitations

  • Small sample.
  • No control group.
  • High dropout and non-initiation.
  • Dietary meal replacement cointervention.
  • Incomplete adherence tracking and limited follow-up return.

Safety

  • No adverse events were reported.
  • Screening excluded contraindications and allowed PCP concern to stop enrollment.