Moderate intensity exercise in hypoxia increases IGF-1 bioavailability and serum irisin in individuals with type 1 diabetes

Abstract

Aim: This study aimed to determine the effect of moderate intensity continuous exercise (Ex) and hypoxia (Hyp) on serum brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and its binding protein-3 (IGFBP-3), irisin and cytokines levels in patients with type 1 diabetes (T1D). Methods: A total of 14 individuals with T1D (age: 28.7 ± 7.3 years) and 14 healthy adults (age: 27.1 ± 3.9 years) performed 40-min continuous Ex at moderate intensity (50% lactate threshold) on a cycle ergometer in normoxia (Nor) and Hyp (FiO2 = 15.1%) Biochemical factors, glucose concentrations and physiological variables were measured at rest, immediately and up to 24 h after both Ex protocols. Results: Patients with T1D had significantly lower pre-Ex serum concentrations of BDNF ( p < 0.05, p < 0.01), and total IGF-1 ( p < 0.001, p < 0.05) and significantly higher irisin levels ( p < 0.05, p < 0.01) in Nor and Hyp, compared with healthy subjects. Ex significantly increased in T1D group serum BDNF (in Nor only p < 0.05) and total IGF-1 levels in Nor and Hyp ( p < 0.001 and p < 0.01, respectively). Immediately after Ex in Hyp, freeIGF-1 ( p < 0.05) and irisin levels ( p < 0.001) were significantly higher compared with the levels induced by Ex alone. Free IGF-1 and irisin serum levels remained elevated in 24 h post-Ex in Hyp. In T1D, significant blood glucose (BG) decrease was observed immediately after Ex in Hyp ( p < 0.001) and in 24 h recovery ( p < 0.001) compared with pre-Ex level. Conclusion: The study results suggest that moderate intensity continuous Ex has beneficial effect on BDNF and IGF-1 levels. Ex in hypoxic conditions may be more effective in increasing availability of IGF-1. The alterations in the post-Ex irisin levels and IGF-1 system may be contributing to more effective glycaemia control in patients with T1D.

Combined Aerobic and Resistance Training Performed under Conditions of Normobaric Hypoxia and Normoxia Has the Same Impact on Metabolic Control in Men with Type 1 Diabetes

“…Nevertheless, it has been shown that hypoxia promotes lowering of blood glucose levels through the stimulating effect of HIF-1 on glycolysis and as a result of the increased expression of GLUT4 glucose transporters in muscle tissue independently of muscle work [ 13 ]. In one of the few studies in patients with type 1 diabetes, a single 40 min moderate-intensity exercise bout (50% of lactate threshold) on a cycloergometer in hypoxia was associated with a reduction in glycemia immediately after training and within 24 h of recovery compared to the same effort under normoxic conditions [ 11 ]. Regardless of the conditions in which the training took place, it was a moderate effort that usually led to lowering of glycemia in diabetic patients.…”

“…Patients with type 1 diabetes have decreased IGF-1 expression which leads to disturbances in bone metabolism and neuropathy, as well as muscle atrophy and cardiovascular complications. It has been shown that physical exercise performed in conditions of moderate hypoxia (2500 m above sea level) leads to an increase in the concentration of free IGF-1 [ 11 ]. Exercise in hypoxia also increases NO production and lowers the concentration of pro-inflammatory TNF-alpha.…”

Assessing the Induced Adipose Tissue Browning Effects of Hypoxic Swimming and Cold-Water Exposure in Healthy Human Participants Using Contrast-Enhanced Ultrasound (CEUS)

“…Moreover, there is a lack of evidence regarding hypoxic exercise induced AT browning in human participants. However, studies have reported weight loss effects of hypoxic exercise, as well as its inducing WAT browning capabilities in rats, particularly with the upregulation of Irisin and Leptin levels, adipokines associated with AT browning by promoting adipose tissue transdifferentiation into beige adipose tissue as well as direct activation of WAT lipolysis and fatty acid oxidation [29][30][31][32][33]. Moreover, studies exploring the effects of hypoxic physical activity (PA) were usually replicated in a hypobaric environment using chambers or conducting studies in mid-mountain areas, which poses risks and limitations like organ structural changes, that can lead to collapse and fainting, as well as economic and technical difficulties [34].…”

Exercise-Mediated Browning of White Adipose Tissue: Its Significance, Mechanism and Effectiveness

“…However, there are relatively few studies on the browning of WAT by exercise under hypoxic conditions. One study [ 61 ] examined the adipose tissue changes in patients with type 1 diabetes after moderate intensity (50% lactate threshold, 40 min) exercise under normoxia or hypoxia. It was found that the serum irisin level was higher after exercise under hypoxia than under normal oxygen.…”