# Equipment-free, unsupervised high intensity interval training elicits significant improvements in the physiological resilience of older adults

PMID: 35761262
Journal: BMC Geriatrics
Published: 2022
Authors: Sian TS, Inns TB, Gates A, Doleman B, Bass JJ, Atherton PJ, Lund JN, Phillips BE

## Question

Can a short, equipment-free HIIT program improve cardiorespiratory, cardiometabolic, and muscle outcomes in older adults, and can an unsupervised home version work similarly to supervised lab HIIT?

## Summary

In independent older adults, 4 weeks of equipment-free bodyweight HIIT improved anaerobic threshold, VO2peak, peak power, systolic blood pressure, cholesterol markers, and some muscle architecture measures versus a no-exercise control. A home unsupervised version performed similarly to a lab-supervised version, but participants were screened, instructed, and relatively healthy.

## Population

- Independent community-dwelling older adults.
- Sample size: 30
- Age: 71 +/- 5 years
- Sex: 14 male; mixed sex
- Fitness level: Not formally exercising >=2 sessions/week.
- Health status: Disability-free and screened for exercise safety.

## Methodology

- Randomized controlled trial with supervised HIIT, home HIIT, and no-intervention control groups.
- 4 weeks
- Research unit and home/community settings.
- Randomized and controlled study design.

## Protocol

- Equipment-free older-adult HIIT.
- Modality: Bodyweight exercises.
- Work intervals: 1 min.
- Recovery: 90 s active recovery.
- Sets or repetitions: 5 high-intensity efforts.
- Intensity: >85% age-predicted HRmax.
- Session duration: About 12.5 min.
- Frequency: 3 sessions/week.
- Program length: 4 weeks.
- Progression: Pyramid-style session; detailed exercise list not extracted from figure.
- No-intervention control.
- Modality: No prescribed exercise.
- Program length: 4 weeks.

## Outcomes

### Anaerobic threshold
Status: improved
Both supervised and home HIIT improved anaerobic threshold versus control, with no difference between HIIT groups.

L-HIIT +2.27 (0.57 to 3.98) p=0.007; H-HIIT +2.29 (0.59 to 4.00) p=0.006 vs control.

### VO2peak and Wmax
Status: improved
Both HIIT formats improved VO2peak and peak work rate versus control.

VO2peak L +3.05 p=0.005; H +3.45 p=0.002; Wmax about +10.6 W p=0.005 in both.

### Blood pressure and lipids
Status: mixed
SBP, total cholesterol, and non-HDL cholesterol improved; DBP, HDL, glucose/insulin AUC and HOMA-IR did not clearly change.

SBP -6 mmHg in both HIIT groups; p=0.02 L-HIIT and p=0.05 H-HIIT.

### Adherence and safety
Status: improved
All participants completed the intervention with 100% adherence and no adverse safety events.

0 lost to follow-up; 100% adherence/compliance.

## Practical Insights

- A 5 x 1-min no-equipment structure is highly translatable for screened older adults.
- Home HIIT should still include onboarding, monitoring instructions, and eligibility checks.
- Short programs may produce early CRF gains but need longer testing for durability.

## Limitations

- Small sample
- Only 4 weeks
- Healthy independent volunteers
- Diet and habitual activity were not measured
- Home arm still had in-person instruction and resources

## Safety And Adherence

- No adverse safety events were reported.
- Participants were screened and the home arm received protocol materials and pulse oximeter monitoring.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/35761262/) (pubmed)
- [DOI](https://doi.org/10.1186/s12877-022-03208-y) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9238013/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.