Ketone Smell


Experience From - Dan Landry , Harry Strohm , Paul Comet , Scott Weber , Karl King , Martin Fryer ,

Dan Landry

The last few 100s I've finished, my wife has informed me I have a keytone smell that permeates throughout my body as well as my breath. She has also noticed this to a lesser degree when I've been building mileage.

Could this be the result of fat metabolism? It usually subsides after 24-36 hours.

Anyone else experience this or are their spouses keeping quiet?

I've never really had this problem until the last fews years.

Harry Strohm

I am not an expert but it is my understanding that a keytone smell would be associated with protien conversion not fat converson.

Paul Comet

Are you on a diet? Sounds like ketosis. When I fasted on water and vitamin pills for 8 days, I had that smell big-time. I recall reading that the smell comes from muscle tissue being destroyed. But I'm no expert on physiology.

Scott Weber

When Al Howie brought up diabetes and ketones, here's what he was referring to:

When too little insulin is present, your body cannot use glucose for energy. It is then forced to break down fat for energy. Your body produces ketones (acids) and releases them into the blood and urine. When people with Type I diabetes do not take enough insulin, especially in times of stress or illness, ketones are produced. Large amounts of ketones can lead to diabetic ketoacidosis, a medical emergency.

Karl King

Ketosis is a result of profoundly low carbohydrate availability and is normally associated with prolonged starvation. The take home message is: eat something, preferably some carbos. I try to run with an intake of 30 to 50 calories per mile and have never experienced a ketone aroma when I run, though I've noted it in others after a long run.

Dr Martin W. Fryer, (PhD School of Physiology & Pharmacology University of New South Wales)

Without trying to be too technical I think you can probably say that this ketone body smell is a consequence of fat metabolism. It depends on the nature of the smell. The smell of ketone bodies is characteristically sweet (somewhat like the smell of nail polish remover). It is different from an ammonia- like smell that might result from muscle (protein) breakdown. Ketone bodies are synthesized by the liver whenever fatty acid levels are high in the blood.

Under normal conditions there are very few ketone bodies in the blood because they are chewed up as quickly as they are formed. Excess ketone bodies are made by the liver when blood glucose is kept persistently low or when glucose uptake into cells is not working efficiently. This latter situation occurs with insulin-dependent diabetics - the smell of ketone bodies on their breath is a diagnostic sign of their disease.

I can quote the following from an article in 1995 which may help (Mitchell and co-workers - Clinical & Investigative Medicine Volume 18, pages 193-216) : "Ketosis is normal during fasting, after prolonged exercise, and when a high fat diet is consumed." "The absence of ketosis in a patient with hypoglycaemia (low blood glucose) is abnormal"

Taken all together this means that what you are experiencing is normal - and might be made a bit better by taking in more carbo both in training and during a race - as suggested by Karl King.