Related Experiment Video
Updated: Apr 1, 2026

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine
Published on: February 9, 2016
The Diurnal Variation on Cardiovascular Endurance Performance of Secondary School Athlete Student
Chun-Yip Chin1, Gary Chi-Ching Chow2, Kwong-Chung Hung1
1Unit of Associate Degree Studies, Faculty of Liberal Arts and Social Sciences,The Hong Kong Institute of Education, Tai Po, Hong Kong.
Background:
The previous investigations in diurnal variation of endurance sports performance did not reach a consensus and have been limited. This study would be a valuable resource for endurance sports trainers and event managers to plan their training and competition in a specific time of day.
Objectives:
The aim of this study is to find out the diurnal variation in cardiovascular endurance performance in the young athletes.
Materials And Methods:
Thirty five athlete students (15.17 ± 1.62 years) participated in this study. Maximal oxygen uptake (VO2max), post-exercise percentage of maximal heart rate (MHR% post-ex), post-exercise body temperature (BTemppost-ex), and post exercise blood lactic acid level (LApost-ex) were measured in this study. Three non-consecutive testings: A) Morning (09:00-10:00; AM), B) Noon (12:00-13:00; NN) and C) Afternoon (16:00-17:00; PM) were conducted. Participants were required to follow the meal plan and resting schedule for all testing days.
Results:
VO2max was significantly higher at NN (F2. 68 = 3.29, P < 0.05, η2 = 0.088) in comparison with PM. The MHR%post-ex, BTemppost-ex, LApost-ex was not significantly different among three times of day.
Conclusions:
Diurnal effect on endurance performance was found and the highest exercise VO2max was identified at noon. Secondary school students or young athletes are recommended to have sports training related to VO2max at noon for the purpose of maximizing training effectiveness.
More Related Videos
Related Concept Videos
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be...
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...
Factors Influencing Heart Rate
Let us explore the significant factors affecting heart rate, including age, body temperature, posture, acute pain, chemical influences,...
Cardiac 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...
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
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...

