Exploring the Impact of Fruit and Vegetable Enzyme Supplementation on Aerobic Performance and Lactate Response in the Elderly Following High-Intensity Interval Exercise Combine Exergaming: Randomized Experimental Matched-Pair Study
Phase: NA
Conditions: Overtraining Syndrome
Sponsor: Shu-Cheng Lin

Project Title: The Impact of Fruit and Vegetable Enzyme 
Supplementation on Aerobic Capacity, and Blood 
Biochemical Values Following Very Low Volume High-
Intensity Interval Exercise - Feasibility Study of Exercise 
Design Using Motion-Sensing Video Games 
 
 
 
 
Study Protocol 
 
 
 
 
 
 
 
 
File date：15   /   August   /   2023 

Introduction 
Exercise represents a paradoxical element in health management, offering 
substantial benefits yet posing potential risks if not properly moderated [1, 2]. High-
intensity exercise, while efficacious in improving various health parameters, can lead 
to oxidative stress, muscle damage, and inflammation [3, 4]. The oxidative stress 
primarily arises from increased reactive oxygen species production during intensive 
physical activities [5]. Moreover, exercise-induced fatigue serves as a protective 
mechanism against overexertion and consequent injuries[6, 7]. In contemporary fitness 
regimes, HIIE, particularly the Tabata training method, has gained prominence for its 
effectiveness in enhancing aerobic power, fat oxidation, and muscular endurance  [8-
10]. These attributes are especially crucial for the elderly population, a demographic 
that significantly benefits from regular physical activity [11-13] . 
Exergaming, an innovative blend of physical exercise and interactive gaming, has 
emerged as a transformative approach to fitness, especially in engaging diverse age 
groups in regular physical activity. Its efficacy in enhancing key fitness parameters like 
aerobic capacity, agility, and coordination, coupled with its ability to make exercise 
more enjoyable, has been well documented [14-16]. This fusion of technology and 
exercise not only caters to the digital age but also opens avenues for personalized fitness 
experiences, adaptable to various demographic needs [17, 18]. While exergaming has 
been effective across a range of ages, its application in elderly populations presents 
unique opportunities and challenges. As the elderly population seeks safe, engaging, 
and effective exercise methods, exergaming could offer a solution that aligns with these 
requirements. However, integrating HIIE concepts into exergaming for the elderly 
remains a relatively uncharted territory. HIIE, known for its efficiency in improving 
cardiovascular health and metabolic function, could significantly benefit older adults, 
particularly in terms of enhancing functional capacity and overall quality of life [12, 
19]. 
The potential of HIIE within exergaming for the elderly hinges on the balance 
between intensity and safety. While HIIE is beneficial, it is crucial to adapt its intensity 
to suit the physiological capabilities and limitations of older individuals. Research 
indicates that tailored HIIE programs can be both feasible and beneficial for older adults, 
leading to improvements in cardiovascular health, muscle strength, and metabolic 
function [20, 21]. Integrating these concepts into exergaming could further enhance 
adherence and enjoyment, crucial factors in maintaining regular exercise habits in this 
demographic. Furthermore, the interactive and immersive nature of exergaming can 
address common barriers to exercise among the elderly, such as lack of motivation or 
fear of injury. By providing a safe, controlled environment for engaging in HIIE, 
exergaming can potentially transform the perception and experience of high-intensity 
workouts for older adults. This is particularly pertinent given the increasing need for 
innovative exercise interventions that cater to the aging global population [11]. 
Nutritional supplementation, especially with natural fruit and vegetable enzymes, 
presents a promising avenue in augmenting exercise performance through their 
antioxidant, anti-inflammatory, and metabolic benefits [21-28] Such supplementation 
could potentially optimize lactate metabolism and enhance muscle function during 
exercise. Recent advancements in nutritional science have highlighted the significant 
role of natural fruit and vegetable enzymes in enhancing exercise performance. These 

enzymes are increasingly recognized for their multifaceted health benefits, including 
their antioxidant, anti-inflammatory, and metabolic-enhancing properties [21, 22]. 
Notably, their potential impact on exercise physiology, particularly in the context of 
high-intensity workouts, offers a new perspective on improving athletic performance 
and recovery. 
One of the critical areas where these enzymes show promise is in the modulation 
of lactate metabolism. Lactate, often produced in higher quantities during intense 
physical activity, can lead to fatigue and decreased muscle efficiency. The traditional 
view of lactate as merely a byproduct of anaerobic metabolism has evolved, with 
current research acknowledging its role as a valuable energy source during prolonged 
exercise [23]. This shift in understanding opens up new avenues for utilizing enzyme 
supplementation to optimize lactate utilization. Enzymes such as bromelain and papain, 
found in pineapples and papayas respectively, have been studied for their potential in 
improving lactate metabolism. These enzymes are known to facilitate faster clearance 
of lactate from the bloodstream, thereby enhancing recovery and reducing fatigue [26, 
28]. Furthermore, the antioxidant properties of these enzymes play a crucial role in 
combating oxidative stress, which is often elevated during intense exercise regimes [24, 
25]. This reduction in oxidative stress is not only beneficial for immediate recovery but 
also contributes to long-term muscle health and function. Moreover, the anti-
inflammatory actions of these natural enzymes can mitigate the inflammatory response 
often triggered by high-intensity exercise [27]. By reducing inflammation, these 
enzymes may enhance muscle recovery and function, thus allowing for more efficient 
and prolonged exercise performance. This aspect is particularly relevant in training 
regimens where recovery is as crucial as the exercise itself. 
The primary aim of this feasibility study is to examine the effects of fruit and 
vegetable enzyme supplementation on aerobic capacity and blood lactate response in 
elderly individuals engaged in HIIE through an exergaming framework. This study is 
dual-faceted, focusing firstly on the physiological responses and feasibility of an 
exergaming-HIIE regimen tailored for the elderly, and secondly, on the impact of 
enzyme supplementation on enhancing these exercise outcomes. 
Methods  
Participants And Experimental Design 
All participants reported a regular exercise habit (3 times per week within the past 
year). They also completed the Physical Activity Readiness Questionnaire and 
confirmed no history of upper limb skeletal muscle injury or major injury. Participants 
were instructed to avoid strenuous activities and the intake of caffeine or muscle-
enhancing supplements for 24 hours prior to the experiment. Before the study 
commenced, all participants provided personal information, completed health 
questionnaires, disclosed personal medical history, and signed informed consent forms.  
The 16 participants underwent the Exergaming HIIE test as an initial assessment 
(pre-test). Participants engaged in a 5-minute warm-up on a stationary bike, followed 
by HIIE using the Nintendo Switch Ring Fit Adventure design. The training method 
was adapted from the research of [8, 9] and consisted of 8 sets of 20 seconds of 

maximum effort exercise with 30 seconds of complete rest between each set, resulting 
in a total exercise time of 370 seconds. The HIIE design incorporated training modes 
targeting the deltoid, pectoralis major, latissimus dorsi, and quadriceps muscles in the 
Nintendo Switch Ring Fit Adventure. Blood lactate levels, heart rate, and ratings of 
perceived exertion were recorded before, during, and after exercise, and training load 
was quantified using TRIMP. Participants were matched and divided into two groups, 
the enzyme group, and the placebo group, based on their blood lactate levels during 
HIIE. Each group comprised 8 individuals. Supplementation with vegetable and fruit 
enzymes or maltodextrin commenced three days after the pre-test and lasted for a total 
of 14 days. On the 14th day, following the completion of supplementation, the 
participants underwent the Exergaming HIIE test as a post-test. 
Ethical Considerations 
The human research ethics committee of the local university approved this study, 
which was also approved by the human research ethics committee of the National 
Cheng Kung University, Taiwan. (Approval No. NCKU HREC-E-112-419-2). Users 
volunteered for this study and agreed to participate by signing an informed consent 
form. 
Supplementation Protocol 
After the pre-test, the enzyme group consumed 30 mL of vegetable and fruit 
enzymes (The contents include needle-leaf cherries, cherries, apples, cranberries, 
blackberries, black currants, blueberries, beets, broccoli, cabbage, carrots, Concord 
grapes, cranberries, elderberries, kale, oranges, peaches, papayas, parsley, pineapples, 
raspberries, red currants, spinach, and tomatoes, etc.)(Enzyme Village, Chiayi, Taiwan) 
mixed with 150 mL of water twice a day (at breakfast and dinner) for 14 consecutive 
days. The placebo group followed the same protocol but consumed malt syrup (Amazon, 
USA) instead until the end of the study. Participants returned to the laboratory each 
morning to receive the daily supplement, which was administered on-site. Following 
supplementation, participants reported their dinner intake to the researchers, ensuring 
compliance with the prescribed supplementation regimen. 
Exergaming HIIE Test-Combination Of Exergaming And HIIE 
Participants in this experiment engaged in HIIE using the Nintendo Switch Ring-
Con within a laboratory environment. All participants completed pre-test and post-test 
assessments on the same day. The exergame employed in this study was 'Nintendo 
Switch Fitness Adventure,' which ingeniously blends exercise with an adventure 
narrative to deliver both physical workouts and gaming enjoyment concurrently. This 
game is noted for its intuitive, user-friendly interface that accommodates players of all 
ages. It incorporates a specialized fitness ring -a smart accessory that connects to the 
Nintendo Switch console. The sensor system utilized two Nintendo controllers: one 
mounted on the exercise ring and the other secured to the participant’s thigh to enhance 
gameplay interaction. Through the Ring-Con, participants engaged in diverse physical 
activities such as weightlifting, yoga, and aerobic exercises. The fitness ring sensor 
accurately captures and integrates players' movements into the game. The gameplay 
involves unlocking levels and engaging in fitness challenges that are achieved through 
actual physical activities. It offers a wide range of exercise routines targeting various 

muscle groups and provides engaging gaming challenges. The exercise protocol 
included eight sets of 20-second high-effort exercises, interspersed with 30-second rest 
intervals, totaling 370 seconds of active exercise time. Specifically, the fitness game 
mode used was the Adventure Mode in 'Ring Fit Adventure,' comprising exercises 
targeting the pectoralis major, latissimus dorsi, deltoids, and quadriceps muscles 
(Figures 2). 
 
 
Figure 2. Experimental flowchart. Ex-: bout of HIIE test; Post-5 min: after 5 minutes 
of HIIE test; Post-10 min: after 10 minutes of HIIE test. Asterisk (*) indicates 
lactate test. Asterisk (#) indicates test heart rate and RPE. 
Blood Lactate Test 
The blood lactate was measured at five time points: before exercise, after the fourth 
and eighth bouts of exercise, and at 5 and 10 minutes after exercise. The blood lactate 
were analyzed using a Biosen Cline blood analysis system (EKF-diagnostic, Germany). 
Capillary blood samples of 10 μL were collected and added to red blood cell lysis 
reagent and stored at low temperature until analyzed. Prior to analysis, instrument 
standardization and test calibration were performed, and the coefficient of variation 
was determined to be ≤1.5%. The detection range for blood lactate was 0.5-40 mM [31]. 
Training Impulse 
In this study, the exercise load was represented by the TRIMP [32], which is 
calculated as the product of exercise intensity and duration. To accommodate the 
convenience of the experiment, two different TRIMP calculation methods were used, 
including % HRmax (objective) and RPE (subjective). At the end of each exercise bout 
(8 bouts in total) and during the recovery period before the next bout (7 bouts in total), 
participants were asked to report their RPE, and their heart rate was recorded. This 
process was repeated 8 times. 
% HRmax Calculation Method 
During the entire HIIE, the participant's HR was recorded every 5 seconds using a 
heart rate monitor (iHeart Polar, Taiwan) to calculate % HRmax. The block TRIMP 

method developed by S. Edwards [33] was used, which divides the exercise intensity 
into 5 blocks with corresponding weighting factors (Table 1). The weighted score of 
each block was multiplied by the exercise time (min) and then summed to obtain the 
exercise load (arbitrary unit [AU]). The calculation formula is as follows: Exercise load 
= (Z1 exercise time × 1) + (Z2 exercise time × 2) + (Z3 exercise time × 3) + (Z4 exercise 
time × 4) + (Z5 exercise time × 5) 
Table 1 The Edwards' block TRIMP calculation method 
Zone 
Intensity 
Weighted score 
Z1 
50%-60% HRmax 
1 
Z2 
60%-70% HRmax 
2 
Z3 
70%-80% HRmax 
3 
Z4 
80%-90% HRmax 
4 
Z5 
90%-100% HRmax 
5 
RPE Calculation Method 
The TRIMP calculation method of Foster, Hector [34] and Foster, Florhaug [35] 
was used to calculate the exercise load by multiplying the RPE value of each exercise 
segment by the exercise time and summing them up. The RPE scale used in this method 
was the CR-10 version modified by Foster, Florhaug [35] based on Borg, Ljunggren 
and Ceci [36] (Table 2). The calculation formula is as follows: Exercise load (AU) = 
Borg's CR-10 RPE score × exercise time (min) 
Table 2. Borg’s CR-10 RPE 
0 
Rest 
1 
Very, very easy 
2 
Easy 
3 
Moderate 
4 
Somewhat Hard 
5 
Hard 
6 
 
7 
Very Hard 
8 
 
9 
 
10 
Maximal 
Statistical Analysis 
All the data were analyzed by SPSS for Windows 20.0. Data are expressed as the mean 
± standard deviation (SD) and 95% confidence interval (95% CI). A mixed design two-
way analysis of variance (ANOVA) (group × time) was used to compare the variables 
of lactate, heart rate and training impulse between two groups before and after the 14-
days of supplementation. Graphs were generated using GraphPad Prism 8.0 (GraphPad 
Software, San Diego, California, USA). Cohen’s conventions for ES (Cohen d) were 
calculated by the G*Power 3.1 software program (Heinrich-Heine-Universität, 
Düsseldorf, Germany), where the ESs of 0.2, 0.5, and 0.8 are considered small, medium, 
and large, respectively. Statistical significance was set as p < 0.05. 
 

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