The effect of 12 weeks of combined upper- and lower-body high-intensity interval training on muscular and cardiorespiratory fitness in older adults
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.
Methodology
- Adults older than 50 years who were physically active but not doing structured exercise more than twice weekly in the prior year.
- 36 participants.
- 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.
- Intensity: Target peak HR above 90% HRmax with strong verbal encouragement; HR monitored continuously.
- Approximately 6-minute warm-up, 12-20 minutes high-intensity work, and 4-minute cool-down.
- 2 sessions per week with about 72 hours recovery.
- 12 weeks; 24 prescribed sessions.
- Controlled exploratory exercise trial using minimisation allocation to HIT or no-exercise control.
- Leg extensor power, Handgrip strength, Predicted VO2max, and Health-related quality of life were tracked.
Outcomes
Muscular fitness
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
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
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
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.
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
- 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.