A 12 hour indoor cycling marathon leads to a measurable decrease of adipose subcutaneous tissue

In a 12 hour indoor cycling marathon, an athlete has lost 0.4 to 1.2 kg of body mass depending on the time of measurement. Fat mass has decreased by 0.9 kg independent of the time of measurement. Calculated skeletal muscle mass increased by 0.27 to 0.67 kg - depending on the time of measurement. Due to the specific weight of urine, a possibly minimum dehydration was objectified, whereas specific weight right after exercise and 24 h after exercise had the same value. We assume that there was a substantial loss of fat mass, since repeated measurements after exercise showed an increasingly lower body weight and a constantly lower fat mass after exercise independent of the time of measurement. Increase of calculated muscle mass is considered to be due to an intramuscular oedema. In order to confirm results obtained in a case study, a larger number of athletes would have to be analyzed. A possible oedema would have to be objectified by a bioelectrical impedance analysis.