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Updated: Oct 27, 2026
Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
Published on: October 17, 2018
Heart rate variability and cortisol responses to acute low- and moderate-intensity exercise in stress-related
Jenny Kling1, Örjan Ekblom2,3, Robert Persson Asplund2,4
1Department of Health Sciences, The Swedish School of Sport and Health Sciences, Lidingövägen 1, Stockholm, 114 33, Sweden. jenny.kling@gih.se.
Purpose:
Exercise is commonly recommended to support stress regulation and mental health, yet it remains unclear whether these benefits translate to conditions characterized by prolonged stress and fatigue. The aims were to examine whether autonomic and hypothalamic-pituitary-adrenal (HPA) axis responses to a single exercise bout differ between individuals with stress-related exhaustion and healthy controls, and whether responses vary by exercise intensity.
Methods:
In a randomized, counterbalanced crossover design, 30 individuals with stress-related exhaustion (93.3% women; age 46.3 ± 5.89) and 29 healthy controls with a comparable age and sex distribution (93.1% women; age 45.5 ± 5.47) completed two 22-min cycling sessions at workloads corresponding to 40% (low intensity) and 55% (moderate intensity) of estimated maximal oxygen uptake (V̇O₂max) on separate occasions. Heart rate variability (HRV; RMSSD, SD2/SD1, LF/HF) and salivary cortisol were assessed pre-exercise, post-exercise, and 30 min post-exercise, with HRV also assessed during exercise.
Results:
Compared with controls, individuals with stress-related exhaustion showed lower RMSSD overall, with the most apparent between-group differences observed during the post-exercise period. Within the exhaustion group, moderate- compared with low-intensity exercise was associated with lower RMSSD and higher SD2/SD1 and LF/HF, whereas no intensity effects were observed in controls. No between-group differences were observed in HRV during exercise. Cortisol analyses suggested overall group-related differences, without clear differences across time points.
Conclusions:
These findings suggest altered physiological stress-system regulation in stress-related exhaustion and highlight the post-exercise period and exercise intensity as important considerations when tailoring exercise recommendations for this population. The study was retrospectively registered on 05/30/2024 at Clinical Trials.gov, with trial registration number NCT06429423.
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