Comment on “the effect of concurrent exercise training (resistance and interval running) and mindful self-compassion therapy on heart rate variability in type 1 diabetes”

Plain language summary Type 1 diabetes can damage the nerves that control the heart, which is often measured through something called heart rate variability. A recent study reported that combining exercise with a mind-based therapy called mindful self-compassion improved heart rate variability in adolescent boys with type 1 diabetes more than either approach on its own. In this letter, we raise two concerns about that conclusion. First, when we looked closely at the study’s results, almost all of the statistical tests meant to show an added benefit from combining the two therapies were not significant. This means the data support the value of exercise and the therapy separately, but do not clearly show that combining them works better. Second, the study measured long-term average blood sugar, which does not capture the short-term ups and downs in glucose levels. These fluctuations may harm the nerves controlling the heart, so without continuous glucose monitoring, it is hard to know whether the observed heart benefits reflect real changes in blood sugar control.