Related Experiment Video
Updated: Aug 18, 2026
Calculating Heart Rate Variability from ECG Data from Youth with Cerebral Palsy During Active Video Game Sessions
Published on: June 5, 2019
Heart rate variability after isocaloric exercise bouts of different intensities
1Department of Kinesiology, San Francisco State University, San Francisco, CA 94132, USA.
Purpose:
To examine cardiac autonomic modulation, via heart rate variability (HRV), after exercise bouts at 50% (LO) and 80% (HI) of VO2 reserve (VO2R).
Methods:
Thirteen male volunteers (age: 25.7+/-3 yr) exercised on a treadmill at either LO or HI (randomly assigned) on separate days, expending 300 kcal during each bout. During each visit, electrocardiogram (ECG) recordings were obtained during a supine 5-min period before exercise (PRE) and during 30 min of postexercise supine recovery (POST). The last 25 min of POST was divided into five 5-min segments to closely examine postexercise HRV. ECG segments were analyzed for the standard deviation of RR intervals (SDNN), whereas total- (lnTP), low- (lnLF), and high-frequency (lnHF) power were obtained via spectral analysis. LF and HF were further normalized (LFNU and HFNU) to better quantify autonomic balance.
Results:
There were main effects of time and intensity on SDNN such that it was lower than PRE until 15 min POST, and lower after HI. There were significant intensity x time interactions on lnTP, lnLF, lnHF, LFNU, HFNU, and lnLF/lnHF. Post hoc analysis revealed that lnTP and lnLF were lower than PRE up to 20 min POST after HI. lnHF was lower than PRE for 25 min POST for HI, and for 10 min POST for LO. LFNU and lnLF/lnHF were greater, whereas HFNU was lower, compared with PRE up to 15 min POST, and from 20-25 min POST for HI only.
Conclusion:
Exercise at 50% VO2R caused less of a shift in the cardiac autonomic balance, with a quicker restoration of vagal modulation than exercise at 80% VO2R.
More Related Videos
08:27A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
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
Related Concept Videos
01:30Factors Influencing Heart Rate
Let us explore the significant factors affecting heart rate, including age, body temperature, posture, acute pain, chemical influences,...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
01:20Exercise 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...
01:31Regulation of Heart Rates
The SNS increases heart rate through the release of norepinephrine and epinephrine, which act on beta-1 adrenergic receptors in the heart. This action increases the rate of depolarization in the sinoatrial (SA) node, the heart's...
01:17Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be met...
01:25Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...