The combination of exercise and video games, known as exergames, allows for the interaction between individuals and the game by performing standardized movements that can be modulated to involve different skills and energy expenditure. These devices seem to be fun and engaging, with the potential for increasing treatment adherence in home-based cardiac rehabilitation (CR) programs.1 However, few studies have investigated the cardiovascular physiological response, safety, and aerobic exercise intensity in patients with cardiovascular disease (CVD), which are often done using a cardiopulmonary exercise test (CPX), the gold standard for functional assessment of CVD patients.
Therefore, the aim of this study was to compare electrocardiographic, hemodynamic, and CPX variables obtained during exergame session with those during a maximal CPX.
METHODS
Participants were adult men and women, with a previous diagnosis of CVD, on optimal medical therapy and clinically stable. This study was conducted from October 2018 to January 2019, and the study protocol was approved by the Research Ethics Committee of our institution (CAAE: 04684918.1.0000.5440). The exclusion criteria were as follows: hypertrophic or Chagas cardiomyopathy; cardiac valve disease; acute or unstable CVD; inflammatory or other connective tissue diseases; myocardial ischemia in low workload (<3 metabolic equivalents [METs]); and orthopedic, neurological, or cognitive impairment that could limit physical activity.
A ramp protocol for continuous dynamic physical effort on a treadmill was used until exhaustion or limiting signal/symptoms. Respiratory variables were measured using a Vmax Encore 29 ergospirometric system for gas analysis (SensorMedics). Continuous 12-lead electrogram with a CardioSoft Exercise Stress Testing system (GE Medical Systems Information Technologies GmbH) was monitored to assess heart rate (HR), arrythmias, and ST-segment alterations. Blood pressure was assessed over the entire test every 2 min. Ischemic threshold was determined by the HR at the start of >1-mm ST-segment depression and/or a plateau in the O2-pulse increment, indicating failure to augment the stroke volume-CavO2 (CaO2 - CvO2) product throughout exercise. Ratings of perceived exertion were acquired at peak of the test.
Exergame session was performed for 48-72 hr at the same period of the day after CPX by using XBOX 360 with Kinect, and the game used was Kinect Adventures with Reflex Ridge modality. The three first stages of basic level were chosen to reach moderate to high exercise intensity. First, patients were submitted to training how to use the exergame and allow better familiarization with this modality. On the next day, a 20-min exergame protocol was applied and respiratory variables were measured using the same system for CPX. Continuous 12-lead electrogram was also acquired as well as the blood pressure after each three stages. The exergame protocol was preceded by 3 min at rest and 3 min more for recovery (26 min in total). Ratings of perceived exertion were acquired before the recovery.
The Shapiro-Wilk normality test was applied to determine whether the variables studied presented normal distribution. The Student paired t test (for variables following normal distribution) or the Wilcoxon matched pairs test (non-normal distribution) was used to compare the variables. The level of significance was 5% (P < .05), two-tailed, in all analysis.
RESULTS
Eight CVD patients (aged 52.5 +/- 14.3 yr) with left ventricular ejection fraction 38 +/- 15% were evaluated. The CPX was considered maximum (respiratory exchange ratio >1.1) in six (75%) patients. The two remaining patients had the tests terminated because of chest pain and an O2-pulse plateau. A third patient who reached maximum showed >1-mm ST-segment depression concomitant with O2-pulse plateau without symptoms. During the exergame, these three patients kept HR values below the ischemic threshold. The results of the CPX and the exergame are presented in the Table.
DISCUSSION
The mean oxygen uptake (V[spacing dot above]O2) during the exergame play was comparable with the V[spacing dot above]O2 at the anaerobic threshold and corresponded to 54% of V[spacing dot above]O2peak by the CPX. Moreover, the exergame HR mean was slightly above the anaerobic threshold (P = .14), reaching 78% of HRpeak observed in the CPX. These intensities are in accordance with the recommendations from the main guidelines for CR of individuals with CVD.2,3
Interestingly, the peak systolic blood pressure during the exergame was similar to that observed on CPX. These similar values may be explained by the amount of muscle groups involved in each exercise type. Although the CPX has reached a greater intensity of effort, the exergame involves upper- and lower-limb muscles simultaneously, demanding greater muscle perfusion at a given intensity of effort. However, myocardial V[spacing dot above]O2, given by rate-pressure product, was smaller than CPX because of HR response.
The game and the modality used in our study have previously been shown to be feasible and safe in individuals with Parkinson disease.4 However, authors themselves pointed out, as a limitation of the study, the lack of monitoring of cardiac performance during the sessions. The safety was assessed by reports of adverse events during the intervention, such as orthopedic injuries, in the same way that has been evaluated in studies with individuals with CVD.5,6 In this sense, our study presents relevant data regarding the cardiovascular stress caused by this modality, thus offering a safe game option for prescription in CR programs.
Previous studies also investigated the cardiac impact during the exergame in patients with CVD7,8; however, only the HR response was assessed. Studies using respiratory gas analysis during the exergame have been conducted in different health conditions such as cystic fibrosis9 and type 2 diabetes.10 Corroborating our findings, these studies concluded that the exercise intensity reached during the exergame meets the recommended intensity according to the physical training guidelines for those health conditions.
Finally, given the lack of consensus regarding the use of the exergame in CR, the present study shows that specific exergame exercise protocols can provide a safe cardiac stress response with adequate intensity, potentially associated with benefits in improving the aerobic capacity.
The small sample size prevents the generalization of the results; however, by using multiple assessment methods and the comparison with the CPX, this study offers the reasoning for larger randomized clinical trials to confirm the findings.
Valeria Cristina de Faria, PE, PhD
Physical Therapy Department, Federal
University of Minas Gerais, Belo Horizonte, Brazil
Julio Cesar Crescencio, PhD
Eloiza Barbeiro Mella, PT
Camila Quaglio Bertini, PT, MSc
Medical School of Ribeirao Preto, University of
Sao Paulo, Ribeirao Preto, Brazil
Danielle Aparecida Gomes Pereira, PT, PhD
Daniele Sirineu Pereira, PT, PhD
Physical Therapy Department, Federal University
of Minas Gerais, Belo Horizonte, Brazil
Lourenco Gallo Junior, MD, PhD
Marcus Vinicius Simoes, MD, PhD
Medical School of Ribeirao Preto, University of
Sao Paulo, Ribeirao Preto, Brazil
Luciano Fonseca Lemos de Oliveira, PT, PhD
Physical Therapy Department, Federal
University of Minas Gerais, Belo Horizonte, Brazil
REFERENCES