High-intensity interval training improves acute plasma volume responses to exercise that is age dependent

Area of Science:

• Exercise Physiology
• Cardiovascular Health
• Sports Science

Background:

• Plasma volume (PV) is influenced by factors like age, training status, and exercise intensity.
• Sedentary lifestyles are associated with suboptimal cardiovascular parameters.
• Understanding the impact of specific training interventions on PV is crucial for health management.

Purpose of the Study:

• To investigate the effects of a 6-week high-intensity interval training (HIT) program on plasma volume (PV) and blood pressure (BP).
• To assess changes in PV during and after exercise before and after the HIT intervention.
• To explore the relationship between age, body weight, and PV variations in sedentary adults.

Main Methods:

• Thirty sedentary adults (18-71 years, BMI 30.1 kg/m²) underwent a 6-week HIT program.
• Plasma volume changes were calculated using hematocrit and hemoglobin measures during warm-up and after a supramaximal cycling test (SCT).
• Anthropometric, fitness, and blood pressure variables were measured pre- and post-intervention.

Main Results:

• PV decreased significantly after warm-up and SCT both pre- and post-HIT.
• The reduction in PV was less pronounced post-HIT compared to pre-HIT.
• Age correlated positively with PV variations pre-HIT, but this relationship disappeared post-HIT.
• Improvements in systolic and diastolic BP were significantly related to post-HIT PV variations.

Conclusions:

• High-intensity interval training (HIT) can enhance plasma volume and mitigate age-related reductions in PV.
• HIT positively influences blood pressure by improving PV dynamics.
• These findings highlight the cardiovascular benefits of HIT for sedentary populations.