Effects of glucose-lowering agents on cardiorespiratory fitness

Table 2 Effects of metformin on cardiorespiratory fitness in patients with type 2 diabetes and metabolic syndrome

Ref.	Study design	Subjects	Metformin dose and intervention	Results
Boulé et al[22], 2011	Randomized, placebo-controlled, crossover study	10 patients with type 2 diabetes	2000 mg/d	VO2→, respiratory exchange ratio↓
		Age: 58 ± 6 yr	Exercise mode: Treadmill at three different submaximal intensities	Heart rate↑, lactate↑, rating of perceived exertion↑
		Sex: 8 men and 2 women	Study duration: 22 wk
		BMI: 28.6 ± 5.3 kg/m2
		HbA1c: 6.5 ± 0.6%
Boulé et al[23], 2013	Randomized controlled trial (Diabetes Aerobic and Resistance Exercise) trial	251 patients with type 2 diabetes (143 patients treated with metformin and 82 patients treated without metformin)	Approximately 1600 mg/d	VO2peak→
		Age: 54.9 ± 7.1 yr vs 53.1 ± 6.9 yr	Exercise mode: Aerobic training, resistance training, and combined aerobic and resistance training
		Sex (Men/Women): 100/43 vs 46/36	Study duration: 4 wk
		BMI: 33.3 ± 5.5 kg/m2 vs 33.3 ± 6.4 kg/m2
Cadeddu et al[25], 2014	Non-randomized, non-controlled trial	HbA1c: 7.78 ± 0.9% vs 7.47 ± 0.77%	1000 mg/d	VO2peak→
		75 patients with insulin resistance	30–50 min of cycle exercise at the intensity of 60%–80% of the heart rate reserve
		Age: 46.2 ± 11 yr
		Sex: 35 men and 40 women	Study duration: 12 wk
Paul et al[26], 2017	Prospective observational study	BMI: 29.8 ± 4.1 kg/m2	1000 mg/d	VO2max↓
		15 patients with metabolic syndrome	No intervention
		Age: No description	Study duration: 6 wk
		Sex: No description
		BMI: No description (weight: 75.4 ± 12.08 kg)

BMI: Body mass index; HbA1c: Hemoglobin A1c; VO₂: Oxygen consumption.