Intense exercise stimulates albumin synthesis in the upright posture

Area of Science:

• Exercise Physiology
• Biochemistry
• Human Physiology

Background:

• Exercise-induced hypervolemia involves changes in plasma volume and protein content.
• Albumin is a key plasma protein influencing fluid balance and transport.
• Understanding albumin dynamics post-exercise is crucial for recovery and performance.

Purpose of the Study:

• To investigate if elevated albumin synthetic rate contributes to increased plasma albumin during exercise-induced hypervolemia.
• To determine the effect of exercise intensity and recovery posture on albumin synthesis.

Main Methods:

• Seven healthy subjects underwent intense intermittent exercise (85% peak oxygen consumption).
• Albumin synthetic rate was measured using deuterated phenylalanine (d(5)-Phe) infusion.
• Measurements were taken at 1-5 and 21-22 hours post-exercise in upright and supine postures.

Main Results:

• Upright exercise significantly increased albumin fractional synthetic rate (FSR) and absolute synthetic rate (ASR) post-exercise.
• Albumin FSR increased from 4.9%/day to 7.3%/day, and ASR from 87.9 mg/kg/day to 141.1 mg/kg/day.
• No significant changes in albumin FSR or ASR were observed in the supine posture.

Conclusions:

• Increased albumin synthesis after upright intense exercise contributes to expanded and maintained albumin content.
• Posture plays a critical role in modulating the stimulus for albumin synthesis following intense exercise.