The Impact of Sprint Interval Training Frequency on Blood Glucose Control and Physical Function of Older Adults
Question
Does once-weekly versus twice-weekly short sprint interval training improve blood glucose control, physical function, and aerobic capacity in older adults?
Summary
In inactive older adults with controlled hypertension, 8 weeks of supervised cycling sprint interval training once or twice weekly improved physical function and predicted aerobic capacity compared with control. Twice-weekly training produced clearer improvements in 2-hour glucose and glucose area under the curve.
Methodology
- Inactive older adults with stable controlled hypertension and no metabolic or cardiovascular disease.
- 34 participants.
- Cycle ergometer.
- Work intervals: 6 s all-out sprint.
- Recovery: At least 60 s passive recovery or until HR <120 bpm.
- Intensity: All-out against 7% body mass for men and 6.5% for women.
- Short session with 36-60 s total sprint work plus recovery.
- 1 session/week.
- 8 weeks.
- Three-group controlled training intervention
- Blood glucose control, Physical function, and Predicted VO2max were tracked.
Outcomes
2 h glucose
Twice-weekly SIT significantly reduced 2 h glucose; once-weekly did not reach significance but exceeded the smallest worthwhile change.
Group x time p=0.001; twice-weekly p=0.001; once-weekly p=0.249.
Glucose AUC
Twice-weekly SIT significantly reduced glucose AUC; once-weekly did not reach significance but improved beyond SWC.
Group x time p=0.027; twice-weekly p=0.007; once-weekly p=0.124.
Function
Both SIT frequencies improved get-up-and-go and sit-to-stand times.
GUAG group x time p=0.014; STS p=0.001.
Predicted VO2max
Both SIT frequencies increased predicted VO2max by about 1.5 mL/kg/min.
Group x time p=0.002; once and twice p=0.001.
Insights
- For selected older adults, very short supervised cycling sprints may improve function with minimal weekly frequency.
- Use heart-rate recovery thresholds instead of fixed recovery only.
- Twice-weekly volume may be needed for clearer glucose-control changes.
Limitations
- Small sample
- Allocation was not clearly randomized
- Frequency and total sprint volume were confounded
- Predicted rather than directly measured VO2max
- Limited adverse-event detail
Safety
- No adverse events were reported.
- All SIT sessions were fully supervised with continuous heart-rate monitoring.
- Participants had controlled hypertension only; metabolic and cardiovascular disease were exclusion criteria, and recovery continued until at least 60 seconds or heart rate below 120 bpm.