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.”
Effects of vitamin D supplementation and circuit training on indices of obesity and insulin resistance in T2D and vitamin D deficient elderly women.
The purpose of this study was to investigate the effects of vitamin D supplementation and circuit training on body composition, abdominal fat, blood lipids, and insulin resistance in T2D and vitamin D deficient elderly women.
Fifty-two elderly women were randomly assigned to either the vitamin D supplementation with circuit training group (D+T: n = 15), the circuit training group (T: n = 13), the vitamin D supplementation group (D: n = 11), or the control group (CON: n = 13). The subjects in D took vitamin D supplements at 1,200 IU per day for 12 weeks; the subjects in T exercised 3 to 4 times per week, 25 to 40 minutes per session for 12 weeks; and the subjects in D+T participated in both treatments. Subjects in CON were asked to maintain normal daily life pattern for the duration of the study. Body composition, abdominal fat, blood lipids, and surrogate indices for insulin resistance were measured at pre- and post-test and the data were compared among the four groups and between two tests by utilizing two-way ANOVA with repeated measures. The main results of the present study were as follows:
1) Body weight, fat mass, percent body fat, and BMI decreased significantly in T, whereas there were no significant changes in the variables in D and CON. Lean body mass showed no significant changes in all groups. 2) TFA and SFA decreased significantly in T, whereas there were no significant changes in the variables in D and CON. The other abdominal fat related variables showed no significant changes in all groups. 3) TC, TG, HDL-C, and LDL-C showed improvements in T, whereas there were no significant changes in the variables in D and CON. 4) Fasting glucose, fasting insulin, and HOMA-IR tended to be lower in D+T.
It was concluded that the 12 weeks of vitamin D supplementation and circuit training would have positive effects on abdominal fat and blood lipid profiles in T2D and vitamin D deficient elderly women. Vitamin D supplementation was especially effective when it was complemented with exercise training.
PMID: 25566461 [PubMed] PMCID: PMC4241902