# The effect of 12 weeks of combined upper- and lower-body high-intensity interval training on muscular and cardiorespiratory fitness in older adults

PMID: 30051418
Journal: Aging Clinical and Experimental Research
Published: 2018-07-26
Authors: Hurst C, Weston KL, Weston M

## Question

Does a twice-weekly combined upper- and lower-body HIT program improve muscular fitness, cardiorespiratory fitness, and health-related quality of life in adults over 50 compared with no added exercise?

## Summary

A 12-week supervised whole-body high-intensity interval program using a hydraulic resistance ergometer was highly attended and produced small beneficial changes in leg power, handgrip, predicted VO2max, and some quality-of-life domains in adults over 50, with no adverse events reported.

## Population

- Adults older than 50 years who were physically active but not doing structured exercise more than twice weekly in the prior year.
- Sample size: 36
- Age: HIT 61.9 years (range 50-81); control 62.8 years (range 50-74).
- Sex: 21 male and 15 female overall; HIT 11M/7F and control 10M/8F.
- Fitness level: Physically active but not formally trained in systematic moderate-to-high intensity endurance or strength exercise.
- Health status: Generally healthy; excluded for systemic disease, relevant medication, and neuromuscular/skeletal conditions.

## Methodology

- Controlled exploratory exercise trial using minimisation allocation to HIT or no-exercise control.
- 12 weeks
- Instructor-led small-group sessions using Speedflex hydraulic resistance ergometers.
- Controlled study design.

## Protocol

- Combined upper- and lower-body HIT.
- Modality: Speedflex double-concentric hydraulic resistance ergometer exercises.
- Work intervals: 45 seconds per exercise repetition in week 1, increasing by 10 seconds every third week to 75 seconds by week 10.
- Recovery: 15-second transitions between exercise repetitions and 3-minute passive rest between sets.
- Sets or repetitions: Four high-intensity sets; each set contained four exercise repetitions.
- Intensity: Target peak HR above 90% HRmax with strong verbal encouragement; HR monitored continuously.
- Session duration: Approximately 6-minute warm-up, 12-20 minutes high-intensity work, and 4-minute cool-down.
- Frequency: 2 sessions per week with about 72 hours recovery.
- Program length: 12 weeks; 24 prescribed sessions.
- Progression: Repetition duration progressed from 45 to 75 seconds, raising total high-intensity exercise time from 12 to 20 minutes.
- No-exercise control.
- Modality: Habitual physical activity.
- Program length: 12 weeks.
- Progression: No additional structured exercise.

## Outcomes

### Muscular fitness
Status: improved
HIT produced small beneficial between-group changes in leg power and some handgrip measures.

Dominant leg power +10.5% (90% CI 2.4 to 19.4); non-dominant leg +9.4% (3.3 to 16.0); non-dominant handgrip +6.3% (1.2 to 11.5).

### Predicted VO2max
Status: improved
Predicted VO2max improved relative to control.

Between-group effect +8.4% (90% CI 1.8 to 15.4), interpreted by authors as likely small beneficial.

### Adherence and safety
Status: improved
Attendance was extremely high and no adverse events were reported.

429/432 sessions attended (99%); all 18 HIT participants completed; no adverse events during testing or training.

### Intensity fidelity
Status: mixed
Average intensity was high, but not all repetitions met the prespecified high-intensity peak HR criterion.

Mean HR 82 +/- 6% HRmax; peak HR 89 +/- 6% HRmax; HRpeak >=90% HRmax in median 62% of repetitions.

## Practical Insights

- Whole-body interval formats can be feasible for healthy adults over 50 when supervised and scheduled twice weekly.
- High attendance may reflect supervised small-group delivery and flexible rescheduling.
- Machine-based hydraulic resistance limits direct translation to bodyweight app programming, but the work/rest progression is useful.

## Limitations

- Small exploratory trial with low power.
- Allocation was by minimisation and randomization was not clearly described.
- Predicted VO2max from a submaximal step test rather than direct gas analysis.
- No long-term follow-up.
- Participants were relatively healthy and active, limiting generalizability to frailer or multimorbid older adults.
- Industry sponsorship from the equipment provider creates possible conflict risk.

## Safety And Adherence

- No adverse events occurred during testing or training.
- Missed sessions were due to unrelated injury and family commitments.
- Training was instructor-led in small groups with heart-rate monitoring.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/30051418/) (pubmed)
- [DOI](https://doi.org/10.1007/s40520-018-1015-9) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6491660/) (full text)

## Agent Guidance

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