Combined exercise may influence haemoglobin glycation patterns in type 2 diabetes

A study from the UAE suggests that combining aerobic and resistance training may reduce HbA1c levels and alter haemoglobin glycation profiles in adults with type 2 diabetes, highlighting the complex biological effects of exercise on glucose processing.

Physical activity may do more than improve average glucose in people with type 2 diabetes; it may also change the way haemoglobin becomes glycated, according to a cross-sectional study from the United Arab Emirates published in Dove Medical Press. The study examined the haemoglobin glycation index, or HGI, a measure that compares observed HbA1c with the level predicted from fasting glucose, alongside a panel of muscle- and fat-derived signalling proteins in adults attending a diabetes clinic in Ajman. HbA1c is widely used to track longer-term glucose control, but, as the National Centre for Biotechnology Information notes, it reflects non-enzymatic glycation of haemoglobin and can vary for reasons beyond average blood sugar.

The researchers analysed 185 adults with type 2 diabetes, split almost evenly between physically active and sedentary participants. Those who exercised regularly had lower fasting glucose, lower HbA1c and lower body mass index than those who did not. More strikingly, their HGI values were substantially lower and more negative, suggesting that their measured HbA1c was closer to, or even below, what would be expected from fasting glucose alone. The study also found that the spread of HGI was wider among sedentary participants, pointing to greater variability in glycation patterns in the less active group.

Exercise type appeared to matter as well. Among active participants, those who combined aerobic and resistance training had the most favourable metabolic profile, including the lowest body mass index, the lowest HbA1c and the lowest HGI. Aerobic-only exercisers had the least favourable pattern within the active group, while resistance training sat between the two. The combined-training subgroup was small, so the authors described those comparisons as exploratory, but the direction of the findings fits with broader evidence that mixed exercise programmes can produce stronger improvements in glycaemic control than single-modality routines.

The biomarker findings were more nuanced. In active participants, IL-6 was inversely associated with HGI after adjustment for multiple testing, while IL-15 showed a weaker positive relationship that did not hold up after correction. In sedentary participants, leptin was the clearest inverse correlate of HGI, again remaining significant after false-discovery-rate adjustment. The authors also reported that adiponectin was unexpectedly higher in sedentary participants, a result they said could reflect medication effects, differences in body composition or compensation for greater insulin resistance. Because the study was cross-sectional and based on single fasting measurements, it cannot show whether exercise changes these biomarkers or whether people with different glycation patterns are simply more likely to exercise.

In multivariable median regression, physical activity remained an independent predictor of lower HGI even after accounting for age, sex, body mass index and selected biomarkers. Fasting glucose explained part of the association, but not all of it, suggesting that activity may relate to glycation biology through pathways beyond average glycaemia alone. The authors pointed to possible roles for oxidative stress, red-cell turnover and intra-erythrocytic glucose handling, although those mechanisms were not directly measured. They also stressed that the resistance and combined-exercise groups were too small for firm conclusions, and that self-reported activity levels may have introduced misclassification.

The study adds to a growing picture of type 2 diabetes as a highly heterogeneous condition shaped not only by glucose levels, but also by how the body processes and responds to that glucose. The World Health Organization describes diabetes as a chronic metabolic disease, and global burden studies in recent years have shown that type 2 diabetes continues to rise sharply worldwide. Against that backdrop, the UAE study suggests that HGI could become a useful marker for identifying people whose glycation profile is out of proportion to their fasting glucose, and that combined exercise may be especially relevant for that subgroup. The findings are preliminary, however, and will need confirmation in larger, prospective studies before they can inform routine care.