Dry Fasting Physiology: Responses to Hypovolemia and Hypertonicity

Area of Science:

• Physiology
• Endocrinology
• Metabolism

Background:

• Dry fasting (DF) involves abstaining from both food and water intake.
• Understanding the physiological adaptations during DF is crucial for its potential therapeutic applications.

Purpose of the Study:

• To elucidate the physiological responses to a 5-day dry fasting period.
• To analyze the hormonal, metabolic, and fluid balance changes during DF.

Main Methods:

• Ten participants underwent a 5-day dry fasting protocol.
• Daily monitoring of serum, plasma, whole blood, and urine parameters, including hormones (cortisol, ADH, ACTH, renin, aldosterone), inflammatory markers (CRP), metabolic indicators (albumin, uric acid), and electrolytes (Na+, K+).
• Body weight, waist circumference, and weight loss composition were also assessed.

Main Results:

• Significant increases observed in stress hormones (ACTH, cortisol), renin-angiotensin-aldosterone system components, and inflammatory marker CRP.
• Marked decreases in body weight, waist circumference, and erythropoietin, alongside significant changes in fluid balance indicators.
• Analysis revealed urine as the primary component of weight loss (52.2%), followed by insensible water loss (32.2%).

Conclusions:

• Dry fasting induces significant physiological adaptations, including hormonal stress responses, immune stimulation, and anti-inflammatory effects.
• The study provides a comprehensive analysis of weight loss components during DF.
• Findings suggest potential applications of DF in managing edema, obesity, and inflammatory/ischemic conditions.