From Ergo Log
A supplement containing extra vitamin D can boost the positive effects of circuit training on body composition discovered sports scientists at Kyung Hee University in South Korea. This is probably because the combination of circuit training and vitamin D supplementation makes the muscles more sensitive to insulin.
The researchers performed an experiment with over fifty women, all of whom were over 65 and overweight. Most of them had type-2 diabetes and all of them had too little vitamin D in their blood. In developed countries most people have less vitamin D in their bodies than scientists consider optimal. [Mayo Clin Proc. 2013 Jul;88(7):720-55.]
The researchers divided the women into four evenly sized groups.
One group took 1200 units vitamin D daily.
A second group did circuit training that took 30-60 minutes three or four times a week. The training consisted of “push-ups with knees against the floor, running on the spot, squats, walking in place, good morning exercises, step-ups, stair-climbing, side lunges, high jumps with open arms, and leg-lifts”. “The 10 kinds of movements above were performed without any break time in 1 set, which lasted for 1 minute”, the Koreans wrote.
A third group took vitamin D and did circuit training as well.
Finally there was a control group that got no extra vitamins and didn’t train either.
The combination of supplement and circuit training had a better effect on body composition than supplementation and circuit training separately.
The figure above shows that none of the strategies had a convincing effect on the fat percentage. But when the researchers looked at the fat in the abdominal region they observed that circuit training did lead to a decrease in this fat. The combined strategy seemed to work a little better than circuit training alone.
When the women’s blood was analysed it became clear that it was the combination of circuit training and vitamin D supplementation that made the women healthier. The combination [D+T] lowered the concentration of triglycerides considerably.
The insulin sensitivity of the women in the combination group increased dramatically. The Koreans believe that this explains why the combination of vitamin D supplementation and circuit training improved their subjects’ body composition.
“From the results of this study, it was concluded that vitamin D intake and circuit training for 12 weeks would have a positive effect on the abdominal fat and blood lipid of elderly women with vitamin D deficiency and type 2-diabetes”, the Koreans write in summary. “In particular, the most important information obtained in this study is that in situations where vitamin D intake is combined with exercise training, the improvements in body composition, abdominal fat, blood lipid, and insulin resistance index are greater than situations with one single treatment.”
J Exerc Nutrition Biochem. 2014 Sep;18(3):249-57.