Effect of exercise on key pharmacokinetic parameters related to metformin absorption in healthy humans: A pilot study.

Exercise is widely accepted as having therapeutic effects; thus, it is important to know whether it interacts with medications. The aim of the present pilot study was to examine the effect of high-intensity interval exercise (known to have antidiabetic action) on key pharmacokinetic parameters related to absorption of metformin (the first-line medication against type 2 diabetes). Ten healthy men participated in two sessions, spaced one to two weeks apart in random, counterbalanced order. In both sessions, participants received 1000 mg of metformin orally, 1-1.5 hours after breakfast. Then, they either ran for 60 minutes at alternating intensity, starting at 40 minutes after metformin administration, and rested without food consumption over the next 3 hours or they rested without food consumption during the entire testing period. Venous blood samples were collected before and at 0.5, 2, 2.5, 3, 3.5, 4, and 4.5 hours after metformin administration for metformin determination by liquid chromatography-mass spectrometry. Capillary blood samples were also collected for lactate and glucose measurements. Data from the two sessions were compared through Wilcoxon or Student's t test, as appropriate. Maximum plasma concentration of metformin (Cmax ) was higher at exercise compared to rest (P = .059). Time to reach Cmax (Tmax ) decreased with exercise (P = .009), and the area under the metformin concentration vs time curve was higher at exercise (P = .047). The addition of exercise to metformin administration did not cause hypoglycemia or lactic acidosis. In conclusion, our results provide the first evidence that pharmacokinetic values related to metformin absorption are affected by exercise.

Relevance of a Sprint Interval Swim Training Set to the 100-Meter Freestyle Event Based on Blood Lactate and Kinematic Variables.

Sprint interval training (SIT) sets are commonly used by coaches in the training routine of swimmers competing in short-distance events; however, data regarding their relevance to competitive events are scarce. The aim of this study was to examine whether performance variables differed or correlated between a 4 × 50-m maximal swimming set (with a work-to-rest ratio of 1:4) and the 100-m freestyle event. Eleven male and 16 female competitive swimmers aged 16.1 ± 1.1 years participated in the study. All swimmers trained at least six times a week and had training experience of more than 4 years. They completed the two freestyle tests on different days, in random and counterbalanced order. In each test, speed, blood lactate, stroke rate (SR), and stroke index (SI) were measured. Speed, blood lactate, and SR were higher at the 4 × 50 m compared to the 100 m and were positively correlated between tests (p < 0.001). The SI did not differ significantly, but was positively correlated between tests. Males were faster and had a higher SI than females, but genders did not differ in lactate. Since performance variables were better in the SIT set and correlated with those in the 100-m bout, we suggest that the 4 × 50-m set can be used to improve performance in the 100-m freestyle event. Moreover, this set can help coaches identify which swimmers will swim fastest in the event.