Introduction

Due to the daily rhythm of insulin level, an increase of the morning fasting blood sugar value was known in prediabetes statements. ECG heart rate variability (HRV) parameters like low-frequency (LF) and high-frequency (HF) also have a circadian pattern. The ratio of LF/HF can show the activity of the autonomic nervous system.
The evaluation of the epidemiological and metabolic aspects of lifestyle (effects of missing meals, high carbohydrate intake, night shift etc.) could help find a more accurate pathophysiological knowledge to improve overweight in therapy-resistant patients and clearing the risk of it.

Aims & Methods

Our aim was to compare the results of the mother-child group described in our reference abstract and the group performing physical work during night shift. Searching long-term effects of regular night shift physical work and staying awake, such as anaerobic exercise. Could more objective effects on weight loss or on cardiovascular risk be identified than mentioned in other night shift studies?
17 mothers (M) and 24 children (Ch) consecutively, and 24 night shift employees (NS) were examined in the morning after their night shift. The epidemiological parameters were evaluated, then the oral loading test with orally intake of 75 g of glucose was performed. We checked the venous blood gas parameters to follow mitochondrial function indirectly. The function of the autonomic nervous system was determined by a 2-minute resting HRV and LF/HF values.

Results

Our groups (mean+SD): age were M=48.8 +/- 5.1 vs. Ch=23.5+/-5.4, vs. NS=45.7+/-10.0. The averages of BMI were M=28.59 vs. Ch=31.65 vs. NS=31.56.
The 0-minute insulin: M=5.4 +/- 3.43 vs. Ch=9.0+/-4.13, vs. NS=10.17+/-5.06 which is significant according to Student's t-test, p(M-Ch)=0.003. p(M-NS)= 0.001. The lifestyle differences were irregularity and skipping of the breakfast in the NS group.
The venous lactate was after 120 minutes of the glucose intake (mean +/- SD) M=1.37 +/-0.52 vs. Ch=1.56 +/-0.43, vs. NS=1.51 +/-0.19. Lactate reference value (Siemens Epoc Reader) <0.75 mmol/l, p (M-Ch)=0.005, vs. p(M-NS)=0.003. The 0-minute lactate values were M=1.03+/-0.44 vs. Ch = 1.02 +/- 0.31, vs. NS = 1.17 +/- 0.48. p>0.05. HRV LF/HF values (mean+/- SD) were M= 1.2+/-0.54, vs. Ch=1.05 +/-0.59 vs. NS=0.74+/-0.23, p(M-NS) =0.025, p(M-Ch)>0.05. The venosus partial pressure of oxygen (average +/- SD) were M=28.2 +/- 7.22 vs. Ch=29.8+/-7.26, vs. NS=26.8+/-6.55. p(M-NS)>0,05.

Conclusion

The higher basal insulin and lactate level and lower venosus partial pressure of oxygen in the NS group could be explained by a relative tissue hypoxia which a factor of anaerobic metabolism and could increase the consumption of glucose in the muscles by GLUT4 transporters and elevating the level of circulating glucose.
The vagus tone helped in the dynamic autonomic regulation and it was responsible for cardiovascular health. Its decreasing correlates with the lower LF/HF ratio, which could be a marker for physical overload of the NS group.
Unsuccessful weight loss could be explained with the proportionally higher insulin level in NS group, which causes a feeling of hunger and helps the fat storage. On the other hand, the lower effectiveness of calorie-restricted diets should be improved with regular meals during night shift.
We presented a possible clinically measurable sign of the pathophysiological features of the adipose tissue hypoxygenisation as in hypoxia inducible factor 1-alpha studies presented.
We were planning a long-term health risk study to demonstrate the effectiveness of these parameters.

References

UEG 2023 Abstract 642 and 1400