Related Experiment Video
Updated: Feb 26, 2026

A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
Four-week "living high training low" program enhances 3000-m and 5000-m time trials by improving energy metabolism
Hun-Young Park1, Sungho Kim2, Sang-Seok Nam2
1Performance Activity and Performance Institute, Konkuk University, Seoul, Republic of Korea.
Purpose:
This study aimed to determine the effect of a 4-week living high training low (LHTL) versus a living low training low (LLTL) program on energy metabolism during submaximal exercise and 3000-m and 5000-m time trial (TT) in athletes.
Methods:
Male athletes (n = 20) were randomly assigned to the LLTL (n = 10, living at 1000 m and training at 700-1330 m) and LHTL (n = 10, living at simulated 3000 m and training at 700-1330 m) groups. We compared energy metabolisms during submaximal exercise on a treadmill and aerobic exercise performance (3000 m and 5000 m TT) before and after 4 weeks of training.
Results:
As expected, the LHTL group demonstrated enhanced energy metabolism during submaximal exercise via significant interaction (time × group) in heart rate, oxygen consumption, and carbon dioxide excretion; these variables were significantly decreased in the LHTL group compared with the LLTL group. Additionally, both training groups revealed significantly decreased blood lactate levels during submaximal exercise, 3000 m TT, and 5000 m TT but significant interactions (time × group) in the 3000 m and 5000 m TT. Thus, the LHTL group demonstrated greater improvements in 3000 m and 5000 m TT than the LLTL group via significant interactions.
Conclusion:
Our results suggest that 4-week LHTL intervention enhances 3000 m and 5000 m TT by improving energy metabolism during submaximal exercise. The proposed LHTL intervention in this study is a novel and effective method for improving aerobic exercise performance in male athletes.
Related Concept Videos
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be...
Muscle Recovery and Fatigue
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...
Metabolic Rate
The Basal Metabolic Rate (BMR) measures the energy expended at rest.
Several factors influence...

