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Updated: Apr 23, 2026
A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
Differential cardiac effects of aerobic interval training versus moderate continuous training in a patient with
Marco Herbsleb1, Tobias Mühlhaus2, Karl-Jürgen Bär2
1Pain and Autonomic Integrative Research (PAIR), Department of Psychiatry and Psychotherapy, University Hospital Jena , Jena , Germany ; Clinical Exercise Physiology (CEP), Department of Sports Medicine and Health Promotion, Friedrich-Schiller-University , Jena , Germany.
Insights
Interval training (IT) significantly improved heart rate variability (HRV) and reduced resting heart rate (HR) in a schizophrenia patient, unlike moderate continuous training (CT). These benefits, however, diminished after detraining.
Area of Science:
- Cardiology
- Psychiatry
- Exercise Physiology
Background:
- Patients with schizophrenia face higher cardiovascular morbidity and mortality, linked to lifestyle factors and reduced vagal activity.
- Cardiovascular complications are a leading cause of premature death in individuals with schizophrenia.
- Reduced vagal tone is a potential mechanism contributing to cardiac issues in schizophrenia patients and their relatives.
Purpose of the Study:
- To compare the effects of moderate continuous training (CT) and interval training (IT) on cardiovascular regulation in a patient with chronic schizophrenia.
- To investigate the impact of different aerobic exercise regimes on heart rate (HR) and heart rate variability (HRV).
Main Methods:
- A case study involving one patient with chronic schizophrenia undergoing a 6-week CT period followed by a 6-week IT period on a stationary bicycle, with a subsequent 6-week detraining phase.
- Primary outcomes measured resting HR and HRV; secondary outcomes assessed fitness parameters like ventilatory threshold 1 (VT1).
Main Results:
- Interval training (IT) demonstrated superior efficacy over moderate continuous training (CT) in enhancing HRV (27% vs. 18% improvement) and reducing resting HR (-14% vs. 0% change).
- Improvements in VT1 were observed only after the IT period (21% increase), while CT showed no significant change (-1%).
- The positive effects of IT on HR regulation were lost after a short detraining period.
Conclusions:
- The type of aerobic exercise intervention significantly influences cardiovascular regulation improvements in patients with schizophrenia.
- Interval training appears more effective than moderate continuous training for enhancing cardiac function in this patient population.
- The benefits of interval training on heart rate regulation are transient and susceptible to detraining.
Abstract:
Increased cardiovascular morbidity and mortality rates for patients with schizophrenia are reported to contribute to their reduced life expectancy. Common reasons for increased cardiac mortality rates include cigarette smoking, obesity, dyslipidemia, diabetes, and poorer health behavior in general. The majority of excess mortality among people with schizophrenia is caused by cardiovascular complications. Reduced vagal activity might be one important mechanism leading to this increased cardiac mortality and has been consistently described in patients and their healthy first-degree relatives. In this case study, we compared two different aerobic exercise regimes in one patient with chronic schizophrenia to investigate their effects on cardiovascular regulation. The patient completed a 6-week period of moderate continuous training (CT) followed by a 6-week period of interval training (IT), each regime two times per week, on a stationary bicycle. This was followed by a 6-week period of detraining. Primary outcome measures examined heart rate (HR) and heart rate variability (HRV) at rest while secondary measures assessed fitness parameters such as the ventilatory threshold 1 (VT1). We observed that IT was far more effective than moderate CT in increasing HRV, as indicated by root mean of squared successive difference (improvement to baseline 27 versus 18%), and reducing resting HR (-14 versus 0%). Improvement in VT1 (21 versus -1%) was only observed after IT. Our study provides preliminary data that the type of intervention is highly influential for improving cardiac function in patients with schizophrenia. While cardiovascular function might be influenced by CT to some degree, no such effect was present in this patient with schizophrenia. In addition, the beneficial effect of IT on HR regulation vanished completely after a very short period of detraining after the intervention.
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