Actual vs. perceived exertion during active virtual reality game exercise.

Background: Virtual exercise has become more common as emerging and converging technologies make active virtual reality games (AVRGs) a viable mode of exercise for health and fitness. Our lab has previously shown that AVRGs can elicit moderate to vigorous exercise intensities that meet recommended health benefit guidelines. Dissociative attentional focuses during AVRG gameplay have the potential to widen the gap between participants' perception of exertion and actual exertion. Objective: The aim of this study was to determine actual exertion (AEx) vs. perceived exertion (PEx) levels during AVRGs by measuring heart rate (HR) and ratings of perceived exertion (RPE) in two different settings. Materials and methods: HR and RPE were collected on participants (N = 32; age 22.6 ± 2.6) during 10 min of gameplay in LabS and GymS using the HTC VIVE with the following games played: Fruit Ninja VR (FNVR), Beat Saber (BS), and Holopoint (HP). Results: Participants exhibited significantly higher levels of AEx compared to reported PEx for all three AVRGs (Intensity): FNVR [AEx = 11.6 ± 1.8 (Light), PEx = 9.0 ± 2.0 (Very Light)], BS [AEx = 11.3 ± 1.7 (Light), PEx = 10.3 ± 2.1 (Very Light)], HP [AEx = 13.1 ± 2.3 (Somewhat Hard), PEx = 12.3 ± 2.4 (Light-Somewhat Hard)]. Additionally, participants playing in the GymS experienced significantly higher levels of AEx [12.4 ± 2.3 (Light-Somewhat Hard)] and PEx [10.8 ± 2.5 (Very Light-Light)] compared to the LabS [AEx = 11.6 ± 1.8 (Light), PEx = 10.3 ± 2.6 (Very Light-Light)]. Conclusion: Perceptions of exertion may be lower than actual exertion during AVRG gameplay, and exertion levels can be influenced by the setting in which AVRGs are played. This may inform VR developers and health clinicians who aim to incorporate exercise/fitness regimens into upcoming 'virtual worlds' currently being developed at large scales (i.e., the "metaverse").

A Handheld Metabolic Device (Lumen) to Measure Fuel Utilization in Healthy Young Adults: Device Validation Study.

BACKGROUND: Metabolic carts measure the carbon dioxide (CO2) produced and oxygen consumed by an individual when breathing to assess metabolic fuel usage (carbohydrates versus fats). However, these systems are expensive, time-consuming, and only available in health care laboratory settings. A small handheld device capable of determining metabolic fuel usage via CO2 from exhaled air has been developed. OBJECTIVE: The aim of this study is to evaluate the validity of a novel handheld device (Lumen) for measuring metabolic fuel utilization in healthy young adults. METHODS: Metabolic fuel usage was assessed in healthy participants (n=33; mean age 23.1 years, SD 3.9 years) via respiratory exchange ratio (RER) values obtained from a metabolic cart as well as % CO2 from the Lumen device. Measurements were performed at rest in two conditions: fasting, and after consuming 150 grams of glucose, in order to determine changes in metabolic fuel usage. Reduced major axis regression and simple linear regression were performed to test for agreement between RER and Lumen % CO2. RESULTS: Both RER and Lumen % CO2 significantly increased after glucose intake (P<.001 for both) compared with fasting conditions, by 0.089 and 0.28, respectively. Regression analyses revealed an agreement between the two measurements (F1,63=18.54; P<.001). CONCLUSIONS: This study shows the validity of Lumen for detecting changes in metabolic fuel utilization in a comparable manner with a laboratory standard metabolic cart, providing the ability for real-time metabolic information for users under any circumstances.

Metabolic Cost and Exercise Intensity During Active Virtual Reality Gaming.

OBJECTIVE: The aim of this study was to investigate the exercise intensity of active virtual reality games (AVRGs) by oxygen consumption (VO2), heart rate (HR), and rating of perceived exertion (RPE). A second aim was to compare the AVRG intensities to current American College of Sports Medicine exercise guidelines using metabolic equivalents (METs) and %VO2 reserve (%VO2R). MATERIALS & METHODS: HR, VO2, and RPE were collected on participants (N = 41; age: 25.2 ± 4.4 years) during 10-minutes of supine rest and while the participants played each of the following AVRGs for 10 minutes: Thrill of the Fight (TOF), Audioshield (AS), and Holopoint (HP). RESULTS: Compared to resting values of HR (63 ± 10 bpm) and VO2 (4.9 ± 0.6 mL/[kg·min]), there were significant elevations in these variables during TOF (149 ± 16 bpm and 32.5 ± 7.1 mL/[kg·min]), AS (131 ± 24 bpm and 19.1 ± 5.9 mL/[kg·min]), and HP (135 ± 22 bpm and 24.8 ± 6.6 mL/[kg·min]). Based on 95% confidence intervals (CI) of %VO2R, TOF was classified vigorous (68.6% ± 2.8%), HP moderate (49.7% ± 2.7%), and AS light intensity (35.7% ± 2.4%). The 95% CI of METs indicated that TOF was classified vigorous (9.3 ± 0.3 METs), HP moderate to vigorous (7.1 ± 0.3 METs), and AS moderate intensity (5.5 ± 0.3 METs). Lastly, 95% CI of RPE led to TOF being classified as moderate (12.7 ± 0.4), whereas HP (10.5 ± 0.4) and AS (9.3 ± 0.3) were light intensity. CONCLUSIONS: These data suggest that these AVRGs can elicit significant increases in VO2 that are game-dependent, indicating increased energy expenditure. Furthermore, each game had a lower intensity categorization based on RPE compared to %VO2R or METs. These data provide information on the metabolic cost of movement-specific games and may aid consumers and fitness specialists in developing exercise programs with AVRGs.

The influence of hydration state on thermoregulation during a 161-km ultramarathon.

It is advised that individuals should avoid losing >2% of their body mass during exercise in order to prevent hyperthermia. This study sought to assess whether a loss of >2% body mass leads to elevations in core temperature during an ultramarathon. Thirty runners agreed to take part in the study. Body mass and core temperature were measured at the start, at three locations during the race and the finish. Core temperature was not correlated with percent body mass change (p = 0.19) or finish time (p = 0.11). Percent body mass change was directly associated with finish time (r = 0.58, p < 0.01), such that the fastest runners lost the most mass (~3.5-4.0%). It appears that a loss of >3% body mass does not contribute to rises in core temperature. An emphasis on fluid replacement for body mass losses of this magnitude during prolonged exercise is not justified as a preventative measure for heat-related illnesses.