Effects of glucose-lowering agents on cardiorespiratory fitness

Table 1 Effects of metformin on cardiorespiratory fitness in healthy individuals

Ref.	Study design	Subjects	Metformin dose and intervention	Results
Johnson et al[18], 2008	Randomized, double-blind, placebo-controlled, crossover study	11 healthy and active men	1000 mg/d	VO2max→, ventilator threshold→, maximal heart rate→, time to fatigue→
		Age: 29.9 ± 3.7 yr	Cycle ergometer at the mean intensity of 69 ± 5.5% of VO2max	Lactate↓, blood glucose concentrations↓
		Sex: All men
		BMI: 25.2 ± 2.8 kg/m2
Braun et al[19], 2008	Non-randomized, placebo-controlled study	18 healthy subjects	2000 mg/d	VO2peak↓, peak heart rate↓, peak ventilation↓, peak respiratory exchange ratio↓, exercise duration↓
		Age: 27.9 ± 3.3 yr	Treadmill or cycle ergometer	Rating of perceived exertion→
		Sex: 11 men and 7 women
		BMI: 24.1 ± 3.6 kg/m2
Malin et al[20], 2010	Non-randomized, double-blind, counterbalanced crossover study	15 healthy and active subjects	2000 mg/d	VO2→
		Age: 25 ± 4.4 yr	Cycle exercise at 5 submaximal cycle workloads	During exercise: Fat oxidation↑
		Sex: 7 men and 8 women		Postexercise: Fat oxidation↓
		BMI: 22.8 ± 2.7 kg/m2
Learsi et al[21], 2015	Randomized, placebo-controlled, counterbalanced study	10 healthy men	500 mg/d	VO2→, maximal accumulated oxygen deficit→, lactate concentrations→
		Age: 23.5 ± 3.6 yr	Cycle ergometer: An incremental test, 6 submaximal workload test at 40%–90% VO2max, 2 supramaximal tests at 110% VO2max	Time to exhaustion↑, VO2 recovery↑
		Sex: All men
		BMI: No description (height: 170.4 ± 4.8 cm, weight: 66.4 ± 6.5 kg)

BMI: Body mass index; VO₂: Oxygen consumption.