Patients with schizophrenia and chronotropic incompetence (CI) do not benefit from aerobic exercise interventions as well as patients with schizophrenia who do not have CI, according to a study recently published in Frontiers in Psychiatry. This finding should be considered when performing interventional studies including exercise.
This study included 43 individuals with multi-episode schizophrenia, as well as 22 healthy controls matched for age and gender, all of whom were given an intervention of standardized cycle ergometer endurance training 3 times weekly for 12 weeks. Inclusion criteria included a schizophrenia diagnosis, as described in the International Statistical Classification of Diseases and Related Health Problems 10th Revision, 2 weeks of antipsychotic medication before initiation of intervention, stable psychopathology, and being aged between 18 and 60 years. Endurance capacity was tested at baseline and at the end of the study intervention. Additionally, 21 participants with schizophrenia were engaged in an extra control intervention of playing foosball. Aerobic fitness and chronotropic exercise response parameters were evaluated. Cardiopulmonary exercise testing was used to measure endurance capacity. Separate multivariate analyses of variance were used to examine differences in heart rate and aerobic fitness values between all participants.
Those with schizophrenia showed significantly lower physical fitness compared with healthy controls (F₍₅,₅₆₎=5.66; P <.001), as well as a higher baseline heart rate (F=11.60; P <.01). An impaired heart response to exercise was found among 10 participants with schizophrenia who were classified with CI, while the condition affected no healthy controls. This did not show significant changes following 12 weeks of aerobic training, nor were the baseline and peak heart rates significantly different among schizophrenia subgroups. Aerobic fitness did not show improvement among those with schizophrenia and also having CI.
Limitations to this study include an exploratory design and a small sample size.
Study researchers “confirm the occurrence of CI in patients with multi-episode schizophrenia. Thorough fitness testing is necessary to reveal CI, but it does not seem to make a difference if the workload during the test is raised continuously or stepwise every 3 min. This should be taken into account when planning an exercise or lifestyle intervention study in patients with schizophrenia.”
Herbsleb M, Keller-Varady K, Wobrock T, et al. The influence of continuous exercising on chronotropic incompetence in multi-episode schizophrenia [published online March 13, 2019]. Front Psychiatry. doi: 10.3389/fpsyt.2019.00090