Ketones and physical activity – what you need to know?
People with diabetes who exercise regularly need to regularly measure not only their blood sugar, but also their ketone levels. New recommendations from Lancet Diabetes & Endocrinology .
Ketones are produced in the body when we mobilize fat for fuel. This process is especially intense during fasting, fasting and long training. The formation of ketones is an important mechanism for the survival of the body, but, in the case of diabetes, we have an increased risk of developing ketoacidosis .
In type 1 diabetes, ketone levels can rise even without fasting. To do this, a too low level of insulin or a jump in hormones such as glucagon or catecholamines (adrenaline, norepinephrine, etc.) is enough.
Symptoms of ketoacidosis include:
- Lack of energy, weakness and fatigue,
- Nausea and vomiting, abdominal pain, loss of appetite,
- Rapid weight loss
- Decreased sweating
- unpleasant sour or fruity breath
- confusion, mild disorientation or confusion,
- in extreme cases – loss of consciousness, coma.
Reasons for developing high ketone levels in type 1 diabetes include:
- Missed insulin injections;
- Problems in the operation of the insulin pump, infusion set;
- spoiled insulin (for example, expired, pre-frozen, exposed to very high temperatures, etc.);
- Ketogenic diet (low in carbohydrates) with a low total daily dose of insulin;
- Prolonged vigorous exercise in conditions of very low insulin levels.
Exercise increases ketone production even in people without diabetes. Increased fat mobilization and increased blood flow to the liver during exercise increases fat absorption by the liver and conversion of fat first to acetyl – CoA and then to ketone body acetoacetate . Acetoacetate can then be converted to two other ketone bodies, acetone and beta- hydroxybutyrate . These ketone bodies then leave the liver and can be used as energy by the muscles.
However, if insulin levels are too low, ketone production becomes greater than their metabolic rate, and blood ketone levels will gradually rise. If there are too many ketones, a person may begin to experience nausea, disorientation, confusion, or weakness. The most dangerous is when the accumulation of ketones occurs asymptomatically.
Very prolonged physical activity, such as hiking, mountain hiking, or marathons, can raise ketones to dangerous levels in people with type 1 diabetes. A combination of factors can be involved in raising ketones to dangerous levels: low insulin levels, prolonged exercise, and stress hormones.
New recommendations published in the Lancet Diabetes & Endocrinology recommends not starting exercise if ketones are elevated. It is necessary to normalize the condition with insulin and carbohydrates before starting sports. This means that before exercise, it is imperative to check both blood sugar and blood ketone levels. The same must be repeated after training. If the loads are prolonged, then measure ketones at the same frequency as glycemia.
Testing for ketones can be done with a ketone meter using additional test strips. If this is not available, use visual test strips (ketones are measured in urine). Blood measurement is best, as this can reveal ketone levels at the time of measurement, whereas urine-based testing actually measures what ketone levels may have been hours ago.
Even though this loads an already demanding list of daily diagnostics, this approach will avoid the need for medical attention and stay active.