Although reports indicate that maximal physical effort can lead to metabolic decompensation, based on incorrect insulin dose (Campbell et al., 2014), increased carbohydrate consumption associated with the fear of hypoglycemia or catecholamine response to intense exercise (Campbell et al., 2014), a recent study has shown that if planned accurately intense exercise is safe in insulin treated diabetics with hyperglycemia >16.6 mmol/L (>300 mg/dL) occurring in 10% of patients while ketone bodies were within reference range (Gawrecki et al., 2017). The gene discussed is INS; the disease is diabetes mellitus.