Complete recovery time after exhaustion in high-intensity work

Abstract

This study was aimed to investigate complete recovery time (CRT) after exhaustion in high-intensity work. Twenty-four subjects were divided into two groups based on the cardiorespiratory capability index, which was measured in a maximum capacity test. Each subject then performed two cycling tests (at 60% and 70% maximum working capacity). The subject continued cycling until exhaustion in each test and then sat recovering until he/she no longer felt fatigue or until the oxygen uptake (VO₂) and heart rate (HR) returned to their baselines, whichever was longer. The results indicated that HR required the longest time to recover and, consequently, HR data were adopted to set the CRT. The CRT was significantly correlated with the cardiorespiratory capability index and the relative workload indices: RVO₂ and RHR. The RVO₂ was the average elevation in VO₂ during work from the resting level as a percentage of maximum VO₂ reserve. The RHR's definition was similar to that of RVO₂. Based on the obtained CRT-prediction model, the CRT for a high-cardiorespiratory-capability person was 20.8, 22.1, 23.4, and 24.7 min at 50%, 60%, 70%, and 80% RHR levels, respectively. These suggested CRT values should be increased by 10 min for a low-cardiorespiratory-capability person.

Keywords:

• Rest time
• Exhaustion
• High-intensity work
• Heart rate
• Oxygen uptake

Acknowledgements

The authors thank the National Science Council of the Republic of China for providing financial support under Project No. NSC91 – 2213-E-324 – 030.