Related Experiment Video
Updated: Feb 2, 2026

A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
Increase interval training intensity improves plasma volume variations and aerobic performances in response to
Fatma Rhibi1, Jacques Prioux2, Mossadok Ben Attia3
1Laboratory of Biomonitoring of the Environment, Faculty of Science of Bizerte, University of Carthage, Tunisia; Laboratory of Movement, Sport and Health (M2S) - EA 1274, University of Rennes 2, F-35000, France.
Purpose:
We studied the effect of two interval training programs of varying intensities (100% vs. 110% of maximal aerobic velocity [MAV]) on hematocrit (Ht), hemoglobin (Hb), and plasma volume variations (PVV) in young men.
Methods:
Thirty-nine male volunteered were assigned to two control groups (CG100, n = 9 and CG110, n = 10), and two training groups (one with 100% MAV [EG100, n = 10] and one with 110% MAV [EG110, n = 10]). All participants performed a maximal graded exercise test and an intermittent exercise (IE) protocol. Blood was collected at rest, at the end of the IE and after 15 min of recovery, before and after 8-weeks-training. Interval training (IT) sessions consist of 30s IE run at 100% or 110% MAV with 30s recovery at 50% MAV.
Results:
After training, time to exhaustion (TTE) was improved in EG110 (+613.7) and EG100 (+397.5). This improvement was greater in EG110 than EG100 (p < 0.005). After training, Hb deceased in EG100 and EG110 at rest (p < 0.01), at the end of IE (p = 0.000) and after 15 min of recovery (p = 0.01). This decrease was more slightly more substantial at rest in EG100 (-0.6%) than EG110 (-0.3%). After training, Ht decreased in EG100 and EG110 at rest (p = 0.001), at the end of IE (p = 0.000) and at 15 min of recovery (p = 0.01). This decrease was more important in EG110 than EG100 at rest (-2.7%), at the end of IE (-2.1%) and after 15 min recovery. After training, PVVrest and PVVend increased in EG100 (+2.2%) and EG110 (+3.2%). No significant difference between EG100 and EG110 was observed.
Conclusion:
Increasing IT intensity by 10% MAV increases PVVrest and PVVend. Despite the fact that EG100 and EG110 had the same PVVend after training, greater performances were recorded in EG110.
More Related Videos
07:40Impact of High-intensity Interval Exercise and Moderate-Intensity Continuous Exercise on the Cardiac Troponin T Level at an Early Stage of Training
Published on: October 10, 2019
09:19Short Session High Intensity Interval Training and Treadmill Assessment in Aged Mice
Published on: February 2, 2019
Related Concept Videos
Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
What is Variation?
The range, standard deviation, standard error, and variance are the different measures of variation.
Range: The range is the difference between its maximum and...
Prediction Intervals
However, the point estimate is most likely not the exact value of the population parameter, but close to it. After calculating point estimates, we construct interval estimates, called confidence intervals or prediction intervals. This prediction interval comprises a range of values unlike the point estimate and is a better predictor of the observed sample value, y.
Variation
When independent and dependent variables are plotted on a scatter plot, the slope of a line is a value that describes the rate of change between the two...
Confidence Intervals
A...