Validation and Impact of Cardiorespiratory Fitness in Severe Mental Illness - the Heart in Mind Project

The revised Ekblom-Bak submaximal cycle-ergometer fitness test (EBsub) will be carried out to estimate VO2max and validated against measured VO2max during a cardiopulmonary exercise test (CPET) including calculation of coefficient variation, limits of agreement, mean absolute percentage error, linear regression analyses for obtaining R-squared values and standard errors of the estimate, and Bland-Altman plotting.

VO2max will be assessed during an incremental cycle protocol until exhaustion conforming to the state-of-the-art CPET. Oxygen consumption and carbon dioxide excretion rates will be measured using a "breath-by-breath" analysing system coupled to a fitted silicone mask, strapped around the participants head, covering nose and mouth (Vyntus CPX, Jaeger). VO2max will be defined as the average of the three highest oxygen consumption measurements.

VO2max will be estimated with the EBsub conforming to the developing authors guidelines.

Non-exercise VO2max estimation with seismocardiography (SCG) will be carried out to estimate VO2max and validated against measured VO2max during a cardiopulmonary exercise test (CPET) including calculation of coefficient variation, limits of agreement, mean absolute percentage error, linear regression analyses for obtaining R-squared values and standard errors of the estimate, and Bland-Altman plotting.

VO2max will be assessed during an incremental cycle protocol until exhaustion conforming to the state-of-the-art CPET. Non-exercise VO2max estimation through SCG will be carried out with the Seismofit(R) (VentriJect, Denmark) device conforming to manifacturers instructions. Breifly, the Seismofit device will be mounted on the sternum, 2 cm proximal to the Xiphoid Process. Before estimation, age, height, weight, and sex of the participant is entered into the VentriJect app. The VO2max estimation lasts ~5min, including recording, data transfer, and signal processing.

Moderate-vigorous physical activity (MVPA) will be assessed with self-reported questionnaires:

International Physical Activity Questionnaire (IPAQ) Physical Activity Vital Sign (PAVS)

And objective measure:

Accelorometry (SENS Motion(R))

self-perceived cardiorespiratory fitness on a 5-point Likert scale rating (i.e., very poor, poor, fair, good, very good) to the question; How do you rate you own physical fitness?

Psychopathology will be assessed with the Positive and Negative Syndrome Scale (PANSS), which provides a structured format for clinicians to evaluate symptom severity in people with psychotic symptoms and/or schizophrenia. Clinicians rate the severity of each symptom on a scale ranging from 1 (not present) to 7 (extremely severe).

Negative symptoms will be assessed with The Brief Negative Symptom Scale (BNSS), which is a standardized clinical assessment tool designed to measure the severity of negative symptoms in individuals with schizophrenia spectrum disorders. Developed as a concise complement to existing scales, the BNSS focuses specifically on assessing five domains of negative symptoms: blunted affect, alogia, anhedonia, asociality, and avolition. Each domain is evaluated through a series of items, with clinicians rating the severity of each symptom on a scale from 0 (absent) to 6 (severe).

Depressive symptoms will be assessed with the modified Major Depression Index (mMDI), which is a refined assessment tool utilized in clinical and research settings to evaluate the severity of major depressive disorder (MDD) symptoms. This index, encompasses key domains of depressive symptomatology, including mood disturbances, cognitive impairments, vegetative symptoms, and psychomotor changes. The mMDI consists of a structured interview format of ten items on a scale of 1 (at no time) to 5 (most of the time).

Global cognition will be assessed with the Brief Cognitive Assessment Tool for Schizophrenia (B-CATS), which is a validated instrument taking approximately ten minutes employed in clinical and research contexts to evaluate cognitive functioning in individuals with schizophrenia spectrum disorders. Developed to efficiently assess cognitive domains relevant to schizophrenia, the B-CATS encompasses key areas such as attention, memory, executive function, and processing speed. The B-CATS includes four tests; 1) Digit Symbol Substitution, 2) Trail Making Test A, 3) Trail Making Test B, and 4) Animal Fluency, which together provides a measure of global cognitive functioning.

Sleep quality will be assessed with the Brief Pittsburgh Sleep Quality Index (B-PSQI) is a shorter version of the PSQI, designed to provide a quick assessment of sleep quality and disturbances. It includes six items from the original PSQI, focusing on key aspects such as subjective sleep quality, sleep duration, and sleep disturbances.

Drug use will be assessed with the Drug Use Disorders Identification Test (DUDIT), which is a validated screening tool designed to assess drug use and related problems in individuals aged 15-65. It consists of 11 items that cover various aspects of drug use, including frequency, quantity, and consequences of use on a 1 to 5 Likert scale. The total score provides an indication of the severity of drug-related problems, with higher scores indicating greater severity.

Alcohol use will be assessed with The Alcohol Use Disorders Identification Test (AUDIT) is a widely used screening tool developed by the World Health Organization (WHO) to assess alcohol consumption patterns and identify individuals at risk of alcohol-related problems. The AUDIT covers three domains: alcohol consumption, alcohol dependence symptoms, and alcohol-related problems. The AUDIT consists of ten items, where each item scored on a Likert scale ranging from 0 to 4.

The total score provides an indication of the severity of alcohol use and related issues, with higher scores indicating greater risk.

Smoking will be assessed with the Fagerström Test for Nicotine Dependence (FTND), which is a validated assessment tool designed to measure the degree of nicotine dependence in tobacco users. The FTND comprises six items that assess various aspects of nicotine dependence, including the intensity of tobacco craving, the frequency of smoking, and the compulsion to smoke in specific situations. The total score provides a quantitative measure of nicotine dependence severity, with higher scores indicating greater dependence.

General quality of life, physical health, psychological, social relationships, environment will be assessed with the World Health Organization Quality of Life-Brief (WHOQOL-Bref) is a validated instrument developed by the World Health Organization (WHO) to assess individuals' quality of life across physical, psychological, social relationships, and environmental domains. Derived from the WHOQOL-100, the WHOQOL-Bref consists of 26 items that cover these four domains, providing an evaluation of subjective well-being. Respondents rate their perceptions of various aspects of life on a Likert scale, with higher scores indicating better quality of life.

Body weight, image, and self esteem will be assessed with the Body Weight, Image, and Self-Esteem (B-WISE), which is a validated assessment tool designed to evaluate the interrelationship between body weight perception, body image dissatisfaction, and self-esteem. The B-WISE comprises 12 items, each item scored on a 1 to 3 Likert scale with higher scores indication poorer adjustment (i.e., never, sometimes, and all the time).

Anthropometrics including height and circumferences will be measured. Height will be assessed without shoes with a wall-mounted stadiometer and waist and hip circumference will be measured with measuring tape, both with a sensitivity of 0.1cm.

Body composition will be assessed with a seca mBCA 514/515 bioelectrical impedance analysis (BIA) machine (SECA GmbH). Utilizing BIA technology, the Seca mBCA 514/515 measures the body's impedance to a small electrical current, which varies based on the amount of water and electrolytes present in different body compartments and tissue. By analyzing the impedance data and applying validated algorithms, the Seca MBCA estimates various components of body composition, including fat mass, fat-free mass, body water, and muscle mass. Additionally, it can estimate visceral adipose tissue when provided with waist circumference.

Systolic and diastolic blood pressure (mmHg) will be assessed when the participant is resting and an average of three measurements with a digital blood pressure device (Rossmax) will be carried out.