Plasma volume change during heavy-resistance weight lifting

Area of Science:

• Exercise Physiology
• Sports Science
• Human Physiology

Background:

• Plasma volume changes are critical indicators of hydration status and physiological stress during exercise.
• Understanding these changes is essential for optimizing athletic performance and recovery protocols.
• Previous research has primarily focused on endurance activities, leaving a gap in knowledge regarding resistance training.

Purpose of the Study:

• To investigate the acute effects of heavy-resistance weight lifting on plasma volume.
• To quantify the magnitude and duration of plasma volume changes following a resistance exercise bout.
• To compare the plasma volume response to resistance training with that of endurance exercise.

Main Methods:

• Six healthy young men participated in the study.
• Participants performed a standardized heavy-resistance weight lifting protocol (70% of one-repetition maximum).
• Plasma volume was calculated using hematocrit and hemoglobin concentrations before, and at several time points after exercise.

Main Results:

• A significant decrease in plasma volume of -14.3% was observed immediately post-exercise (p<0.05).
• Plasma volume remained reduced by -7.0% at 15 minutes into recovery (p<0.05).
• Plasma volume returned to resting levels within 30 minutes of recovery.

Conclusions:

• Heavy-resistance weight lifting induces a substantial and significant reduction in plasma volume.
• The magnitude of plasma volume decrease is comparable to that seen during high-intensity endurance exercise.
• These findings highlight the physiological stress of resistance training and its impact on fluid balance.