The combined effect of high-intensity intermittent training and vitamin D supplementation on glycemic control in overweight and obese adults

Abstract

High‐intensity intermittent training (HIIT) has been shown to reduce the risk of chronic conditions including the development of type 2 diabetes mellitus (T2DM). Independently, a low vitamin D status has also been linked to the prevalence of T2DM. The aim of this study was to investigate if there was a synergistic metabolic effect of HIIT and vitamin D supplementation on glycemic control. A total of 20 male and female participants (age, 34 ± 9 year; BMI, 31.4 ± 2.8 kg·m−2) completed 6 weeks HIIT, and were randomized to ingest 100 μg·day‐1 of vitamin D3 or placebo. Response to an oral glucose tolerance test (OGTT) was determined at baseline and at 72 h postintervention. Glucose tolerance was improved as a result of the HIIT intervention, shown through a reduction in glucose and insulin concentrations during the OGTT, accompanied by a decrease in glucose (829 ± 110 to 786 ± 139 mmol·h−1·L−1; P = 0.043) and insulin (8101 ± 4755–7024 ± 4489 mU·h−1·L−1; P = 0.049) area under the curve (AUC). Supplementation increased 25‐hydroxyvitamin D3 concentration by 120% to a sufficiency status (P < 0.001). However, the consumption of vitamin D3 seemed to attenuate the glucose response during an OGTT. Triglyceride content was lowered following the intervention (P = 0.025). There was no effect of the intervention on insulin sensitivity (IS) indices: ISIM atsuda and HOMA‐IR. Our findings demonstrate that HIIT improves glucose tolerance in nondiabetic overweight and obese adults; however vitamin D3 supplementation did not proffer any additional positive effects on the measured indices of metabolic health.

The Effect of Nordic Walking Training Combined with Vitamin D Supplementation on Postural Control and Muscle Strength in Elderly People—A Randomized Controlled Trial

“…This suggests that a continuous rather than an intermittent type of Nordic Walking training is preferable in inducing the lower limb strength and muscle mass changes in elderly people. Similarly, no relation between the lower limb performance and 25(OH)D concentration has been reported either in the study investigating combined effects of six weeks of HIIT on a cycloergometer and 4000 IU/day Vitamin D supplementation [ 51 ]. However, in the aforementioned study [ 51 ], the participants’ performance increased regardless of the supplementation or placebo intervention.…”

“…Similarly, no relation between the lower limb performance and 25(OH)D concentration has been reported either in the study investigating combined effects of six weeks of HIIT on a cycloergometer and 4000 IU/day Vitamin D supplementation [ 51 ]. However, in the aforementioned study [ 51 ], the participants’ performance increased regardless of the supplementation or placebo intervention. The lack of effect on the lower limb in the HI-NW group could be related different specificities of the applied training load (Nordic Walking vs. cycling), testing (peak torque vs peak power output and VO 2 max) as well as differences in participants’ age (19–45 vs. 62–82 years old).…”

Exercise: A Possibly Effective Way to Improve Vitamin D Nutritional Status

“…Therefore, body fat is significantly negatively correlated with serum 25(OH)D levels [90] and obese individuals have a higher risk of vitamin D deficiency [91,92]. In addition, lipolysis may be impaired in obese individuals [93], and obesity affects the regulation of vitamin D metabolism enzymes [94], which may explain why 25(OH)D levels in overweight and obese adults were not altered in the Lithgow study [48]. Second, exercise in the fed and fasted states differed in terms of energy metabolism substrates.…”

“…Twelve human studies investigated the effect of endurance exercise training on serum 25(OH)D levels and did not yield consistent results (Table 1). Some studies found that chronic endurance exercise training can significantly increase serum 25(OH)D levels [39][40][41][42][43][44][45], but other studies have reported contradicting results [46][47][48][49][50]. However, when we sorted these studies, we found that in people with vitamin D deficiency {25(OH)D < 20 ng/mL or 50 nmol/L [57]}, endurance training can significantly improve serum 25(OH)D levels [39,40,42,43,45], and even severe vitamin D deficiency status (<10 ng/mL) improved to vitamin D deficiency status (10-20 ng/mL) in postmenopausal women [42].…”

“…However, when we sorted these studies, we found that in people with vitamin D deficiency {25(OH)D < 20 ng/mL or 50 nmol/L [57]}, endurance training can significantly improve serum 25(OH)D levels [39,40,42,43,45], and even severe vitamin D deficiency status (<10 ng/mL) improved to vitamin D deficiency status (10-20 ng/mL) in postmenopausal women [42]. However, endurance exercises had no significant effects on serum 25(OH)D levels in overweight and obese subjects, regardless of vitamin D nutritional status [48]. For participants with sufficient vitamin D levels {25(OH)D ≥ 20 ng/mL or 50 nmol/L [57]}, endurance training combined with vitamin D supplementation significantly increased serum 25(OH)D levels [40,44], while endurance training alone did not [40,46,49,50].…”