How does HIIT impact cardiovascular health?
Written by
David Nelson
Reviewed by
Prof. William Dalton, Ph.D.High-intensity interval training markedly improves cardiovascular function through specific physiological adaptations. Cardiac muscle contractility is enhanced, allowing the heart to pump more blood with each beat. Stroke volume is increased, resulting in improved oxygen delivery throughout the body. This again enhances general cardiovascular performance and endurance capacity.
Structural Heart Improvements
- Left ventricle wall thickening increases pumping efficiency
- Resting heart rate decreases 5-8 bpm within six weeks
- Blood plasma volume expands 12-15% improving circulation
- Aortic elasticity enhances reducing systolic pressure
Oxygen Utilization Enhancements
- Mitochondrial density increases 30-40% in muscle cells
- Capillary networks expand around trained muscle fibers
- Myoglobin content rises improving oxygen transport
- Lactate threshold elevates delaying fatigue onset
Lowering blood pressure occurs via improved flexibility of blood vessels. HIIT reduces arterial stiffness by 15-20%. Short-term decreases in systolic blood pressure by 10-15 mmHg occur in hypertensive subjects. Consistent training helps solidify these benefits. Better functioning of the vascular endothelium improves blood flow regulation.
The use of oxygen becomes greatly more effective. The capillary density in trained muscles increases by 20-30%. This delivers oxygen directly to the required area during activity. Mitochondrial biogenesis increases the amount of available energy in the cell. Aerobic capacity is improved more than would be achieved by steady state training alone.
The adjustments in the nervous system support recovery capability. Early reactivation of the parasympathetic response, a system associated with resting states, can speed the recovery of heart rate after exercise. In addition, an increase in heart rate variability indicates enhanced resilience to stress. These benefits reduce the cardiovascular response to everyday activities and similar future exercise.
Read the full article: 10 Key Benefits of High Intensity Interval Training
