PMID 31111021

Research
All papers

Moderate-intensity continuous training: is it as good as high-intensity interval training for glycemic control in type 2 diabetes?

Ahmad AM

Question

Is moderate-intensity continuous treadmill training as effective as high-intensity interval treadmill training for improving HbA1c and estimated average glucose in women with type 2 diabetes?

Summary

In a small 8-week treadmill study of women with type 2 diabetes, both moderate continuous training and 4 x 4 min HIIT improved HbA1c and estimated average glucose. HIIT was significantly better than control, while MICT was not clearly different from control after correction, and HIIT was not statistically superior to MICT. The paper supports that both supervised treadmill approaches can improve glycemic markers in this narrow clinical sample, but the sample was very small and randomization was not clearly described.

Methodology

  • Women with type 2 diabetes, BMI >25 kg/m2, treated with oral hypoglycemic medications.
  • 26 participants.
  • Treadmill walking/running.
  • Work intervals: 4 min at 85-90% HRpeak.
  • Recovery: 3 min active recovery at 65-75% HRpeak.
  • Intensity: Heart-rate targeted from symptom-limited treadmill test.
  • Warm-up plus 4 x 4 min intervals, 3 min recoveries, and 3 min cool-down.
  • 3 sessions/week.
  • 8 weeks.
  • Controlled intervention study with control, MICT, and HIIT groups; group assignment was reported, but randomization was not clearly described in the methods.
  • HbA1c, Estimated average glucose, Adherence and dropout, and Safety screening were tracked.

Outcomes

HbA1c

HbA1c improved within MICT and HIIT groups; HIIT differed from control post-intervention, but HIIT was not significantly better than MICT.

MICT 8.2 to 6.9; HIIT 8.23 to 6.25; post-group p=0.007; HIIT vs control p=0.007; MICT vs HIIT p=0.083.

Improved

Estimated average glucose

Estimated average glucose improved in both exercise groups, with HIIT significantly better than control but not significantly better than MICT.

MICT 188.64 to 151.33; HIIT 189.64 to 136.69; post-group p=0.0102; HIIT vs control p=0.009; MICT vs HIIT p=0.123.

Improved

Completion

Most participants completed the study, but one HIIT participant dropped because the program was difficult.

Analyzed n=26 of 30 assigned; HIIT analyzed n=8 of 10.

Mixed

Insights

  • Use 4 x 4 min HIIT cautiously for diabetes-focused content and pair with medical screening.
  • Because MICT was not clearly inferior, offer moderate continuous alternatives for users who find HIIT too difficult.
  • Do not present this paper as evidence that HIIT beats MICT for glycemic control.

Limitations

  • Very small final sample and group sizes.
  • Women only.
  • Randomization method unclear.
  • No insulin sensitivity or cardiorespiratory fitness outcomes.
  • Short 8-week duration.

Safety

  • No angina occurred during symptom-limited treadmill testing.
  • One HIIT participant discontinued because of difficulty after two sessions.
  • Major cardiopulmonary, vascular, orthopedic, and neurological contraindications were excluded.