Abstract
Background
Obesity has been linked to a higher risk of developing cardiovascular diseases (CVD). The risk of CVD outcomes appears to be stratified by cardiorespiratory fitness (CRF). The study's goal was to determine the relationship between university students’ Body Mass Index (BMI) and CRF.
Methods
BMI and anthropometric measurements of sedentary male (n = 25) and female (n = 18) voluntary physiotherapy students, aged 18–25 years were taken. Pre- and post one minute (post1) and post 5 minutes (post2) six-minute walk test measurements of CRF—including respiration rate (breath per minute), oxygen saturation (in percentage), pulse rate (beat per minute), and blood pressure (mm Hg) were taken. The total distance (in meters) travelled in six minute (6MWDm) was recorded and entered into the formula: Vo2max = −9.824 + (0.072 x 6MWDm).
Results
Males and females had median (IQR) values of BMI (20.75 and 22.15 kg/m2) and Vo2max (27.07 and 24.84 ml/kg/min) respectively. The data was divided into four groups based on body mass index categorization in relation to Vo2max, with negative coefficients of correlation in underweight (−0.18), overweight (−0.26), and obese (−0.33), and positive coefficients of correlation in normal (0.24) individuals. Wilcoxon signed rank test revealed post1 and post2 readings of respiration rate, oxygen saturation, pulse rate and systolic blood pressure were significantly higher than pre readings (p < 0.05).
Conclusion
High obesity rate, weak cardio respiratory fitness and negative relationship between BMI and VO2Max indicate necessity of regular aerobic activities to improve health status among University students.
Keywords
1. Introduction
Body Mass Index (BMI) is divided into four categories according to Asian classification: Underweight (<18.5 kg/m2), normal weight (18.5–22.9 kg/m2), overweight (23–24.9 kg/m2), and obese 1 (≥25–29.9 kg/m2).
1
,2
BMI classification of obesity in individuals younger than 50 years of age has been strongly linked with multi-morbidities in later stages of life. Obesity tends to compromise disease-free survival.3
Certain environmental influences such as lesser physical activity, consumption of trans fats, co-morbidities, diabetes, hypertension, heart and endocrine disorders, malignancies, and so on, adversely impact body weight and increases body mass index.4
The BMI of an individual is crucial in determining probable future health difficulties, and the maintenance of a normal range is an amenable target for a healthy living.4
Transition to higher education has often seen an unfavourable shift towards unhealthy behaviours and increased weight gain,5
with college and university students particularly susceptible to sedentary behaviour. Young adults may generally be motivated to be in good health, with educational institutions and student welfare organisations encouraging them to participate in a variety of physical activities. University students, according to a study, are both sedentary and active.6
Quarantine during coronavirus pandemic has encouraged people to stay at home and work smarter, rather than going outside or to the gym. Due to the restriction on daily purchasing, quarantine may be linked to an unhealthy diet, deficient in fresh foods such as fruits and vegetables and high in processed goods. Obesity and sleep disruption are known to be linked to a poor diet, typified by excessive fat and low fiber intake.7
Cardiorespiratory fitness (CRF) is the ability to deliver oxygen to the mitochondria of the skeletal muscle for the synthesis of energy required during physical activity. Peak alveolar oxygen uptake (Vo2max) is widely used in experiments to determine maximum aerobic power during incremental exercise until volitional exhaustion.8
The characterization of maximum aerobic power or Vo2max may be used to examine cardiorespiratory fitness of an individual. Vo2max is affected by genetics, physical activity, gender, age, and body composition.9
The present study aims to evaluate the body mass index, cardiorespiratory fitness as well as subsequent correlation between these two variables among sedentary physiotherapy students in a regional university of Haryana, India. Early analysis of the situation will help to raise awareness among young individuals to create a healthier lifestyle amending predisposing factors of obesity. It may also help in the creation of evidence-based strategies to alleviate the difficulties associated with obesity, particularly in young adults.2. Methods
2.1 Study design and participants
A strobe based cross sectional survey was conducted between October 2021 and April 2022. The observational study measuredVo2max (ml/kg/min) and BMI (Kg/m2) of physiotherapy students aged 18–25 years of a university in Haryana, India. The study was accepted and approved by the student project committee of Maharishi Markandeshwar Institute of Physiotherapy and Rehabilitation, Maharishi Markandeshwar (Deemed to be) University, Mullana, Haryana, India (2021/1818023). Participants suffering from musculoskeletal disorders, cardiovascular illness, systolic blood pressure >140 mmHg, or diastolic blood pressure <60 mmHg, respiratory disease, or those unable to fully follow the instructions were excluded from the study. The participants with self reported sedentary lifestyle were included. Due to the COVID-19 lockdown situations, the physical presence of physiotherapy students was restricted. Hence from an initial survey of potential 65 participants, 43 participants who volunteered for this study were included and an informed consent was obtained.
2.2 Testing protocol
All participants were assessed and tested by a professional physiotherapist. The testing was carried out on a 100 ft (30 m) indoor track with hard ground that was marked at regular intervals. The 6-min walk test was used to evaluate the Vo2max (ml/kg/min) of the subjects. The total distance (in metres) travelled in 6 min was recorded and placed into the formula: Vo2max = −9.824 + (0.072 6MWDm),
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and height and weight of the subjects for this study were acquired and entered into the body mass index formula: the BMI is calculated as weight (in kg)/height (in m) squared.2.3 Measurements
Participants were encouraged to dress comfortably and wear walking shoes. Prior to testing, all participant baseline data was collected, including age (in years), height (in cm), weight (in kg), pulse rate (beats per minute), respiratory rate (breaths per minute), blood pressure (mm Hg), and oxygen saturation (in percentage) measured. Readings of the same variables were taken at 1 min (denoted by post1) and 5 min (denoted by post2) post completion of test.
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2.4 Statistical analysis
The baseline characteristics were presented using SPSS software, and the normality of all data was confirmed using the Shapiro-Wilk test. The Spearman's test was used to get the correlation coefficient "ρ" between BMI categories and Vo2max values. The Wilcoxon signed rank test was used to compare Respiratory Rate, Pulse Rate, Oxygen Saturation, Systolic Blood Pressure, and Diastolic Blood Pressure between pre reading and post reading (1) and post reading (2).
3. Results
3.1 Demographic details of participants
The students recruited for the study were all from the same institute, hence the sample was homogeneous. The demographic data of the students has been described in Table 1. The data was not normally distributed as determined by the Shapiro-Wilk test (p value below 0.05).
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Table 1Demographic statistics of Age, Height, Weight, BMI, Vo2max and Distance covered in 6 min walk test of participants (n = 43).
| Demographic Data | Median (IQR 25 to 75 percentile) |
|---|---|
| Age(years) | 22.00(21.00–23.00) |
| Height(cm) | 167.00(160.00–176.00) |
| Weight(kg) | 58.00(55.00–71.00) |
| BMI (kg/m2) | 21.64(19.39–24.16) |
| Vo2max(ml/kg/min) | 25.81(23.94–28.91) |
| Distance (m) | 492.00(469.00–526.00) |
Abbreviation -BMI: Body mass index, IQR: Interquartile Ranges, cm: centimeter, m: meter, Kg: kilogram.
3.2 Reading of variables
Table 2 describes the Spearman's correlation test between the classification of BMI and Vo2max. The value of p was greater than 0.05 in four groups, indicating that there was no significant correlation; the value of ρ in group two showed a positive coefficient of correlation (0.24). The relationship between BMI and Vo2max in male and female participants showed inverse relationship using Spearman's correlation test. However the value of p was greater than 0.05, indicating that no significance exists between the variables (Table 3).
Table 2Spearman correlation test between BMI values and VO2Max of participants.
| Category | Asian classification of BMI | No. of student | Median (IQR) of BMI (kg/m2) | Median (IQR) of Vo2max | ρ value | P value |
|---|---|---|---|---|---|---|
| Group one | <18.5 | 4 | 18.01(17.36–18.29) | 29.52(25.81–35.49) | −0.18 | 0.20 |
| Group two | 18.5–22.9 | 21 | 19.78(18.89–21.43) | 25.09(23.07–27.43) | 0.24 | 0.29 |
| Group three | 23–24.9 | 5 | 23.38(23.20–23.47) | 34.38(25.23–39.97) | −0.26 | 0.55 |
| Group four | 25–29.9 | 13 | 25.82(24.36–29.56) | 25.45(24.04–29.09) | −0.33 | 0.44 |
*Spearman test, p < 0.05 as significant.
Abbreviation – IQR: Interquartile Ranges, ρ: correlation of coefficient.
Table 3Spearman correlation test between BMI and VO2Max in Male and Female Participants.
| Participants | Variable | Median (IQR) | ρ value | P value |
|---|---|---|---|---|
| Male = 25 (58.1%) | BMI | 20.75(18.82–24.01) | −0.33 | 0.81 |
| VO2max | 27.07(24.74–33.93) | |||
| Female = 18 (41.9%) | BMI | 22.15(19.65–24.27) | −0.29 | 0.21 |
| VO2max | 24.84(23.65–27.27) |
P < 0.05 show as significant.
ABBREVIATION –IQR: Interquartile ranges.
In Table 4, Table 5 Wilcoxon signed rank was utilised to compare variable readings among male and female participants from pre-readings to post-readings (1) and pre-readings to post-readings (2) in RR, PR OS, SBP, and DBP. The p value in RR, PR, OS, and SBP was less than 0.05, indicating that post-readings (1) and post-readings (2) were significantly higher as compared to pre-reading values separately; however DBP had a p value more than 0.05, indicating no significant difference between pre- and post-values.
Table 4Comparison of pre reading and post reading (1) variables among male and female participant.
| Sno. | Participants | Variables | Median (IQR 25,75) 95% C.I. | Skewness | Kurtosis | Z value | PValue |
|---|---|---|---|---|---|---|---|
| 1 | Male | RR pre reading | 17.00(17.00–18.00) | 0.573 | −0.40 | −4.39 | <0.01* |
| RR post reading (1) | 24.00(22.50–24.50) | −0.29 | −0.78 | ||||
| 2 | Female | RR pre reading | 17.00(16.00–18.00) | 1.245 | 1.95 | −3.74 | <0.01* |
| RR post reading (1) | 23.00(22.00–24.25) | −0.23 | −0.58 | ||||
| 3 | Male | PR pre reading | 85.00(73.50–88.50) | 0.00 | −0.78 | −4.37 | <0.01* |
| PR post reading (1) | 97.00(85.00–106.00) | 0.02 | −1.39 | ||||
| 4 | Female | PR pre reading | 88.00(85.00–92.00) | −0.44 | 0.01 | −3.72 | <0.01* |
| PR post reading (1) | 103.00(99.00–110.50) | −0.27 | −0.28 | ||||
| 5 | Male | OS pre reading | 98.00(97.50–98.50) | 0.24 | 0.52 | −3.57 | <0.01* |
| OS post reading (1) | 99.00(98.00–100.00) | −0.66 | −0.55 | ||||
| 6 | Female | OS pre reading | 98.00(98.00–99.00) | −0.49 | 0.74 | −3.34 | <0.01* |
| OS post reading (1) | 99.00(99.00–100.00) | −0.52 | −0.93 | ||||
| 7 | Male | BP pre reading SBP | 122.00(116.00–129.00) | −0.54 | −0.65 | −4.26 | <0.01* |
| BP Post reading (1) SBP | 133.00(126.00–139.00) | −0.06 | 0.94 | ||||
| 8 | Female | BP pre reading SBP | 114.50(110.00–118.75) | 0.23 | −1.05 | −3.72 | <0.01* |
| BP Post reading (1) SBP | 125.00(120.00–129.25) | −0.07 | −0.90 | ||||
| 9 | Male | BP pre reading DBP | 79.00(75.00–82.50) | 0.55 | −0.20 | −3.31 | <0.01* |
| BP post reading (1) DBP | 84.00(78.50–89.00) | 0.553 | −0.70 | ||||
| 10 | Female | BP pre reading DBP | 74.00(69.50–78.75) | −0.10 | −0.56 | −3.72 | <0.01* |
| BP post reading (1) DBP | 84.00(79.25–86.75) | −0.07 | −0.51 |
*WILCOXON SIGNED RANK TEST, P < 0.05 as significant, ABBERVATION: CI- Confidence Interval, IQR: Interquartile Range, RR: Respiratory Rate, PR: Pulse Rate, OS: Oxygen Saturation, BP: blood pressure, SBP: systolic blood pressure, DBP: diastolic blood pressure.
Table 5Comparison of pre reading and post reading (2) variables among male and female participant.
| Sno. | Participants | Variables | Median (IQR 25,75)95% C.I. | Skewness | Kurtosis | Z value | P |
|---|---|---|---|---|---|---|---|
| Value | |||||||
| 1 | Male | RR pre reading | 17.00(17.00–18.00) | 0.573 | −0.40 | −3.71 | <0.001 |
| RR post reading (2) | 20.00(18.00–20.50) | 0.04 | −0.90 | ||||
| 2 | Female | RR pre reading | 17.00(16.00–18.00) | 1.245 | 1.95 | −3.16 | 0.002 |
| RR post reading (2) | 18.50(18.00–19.25) | 0.30 | 0.45 | ||||
| 3 | Male | PR pre reading | 85.00(73.50–88.50) | 0.00 | −0.78 | −2.62 | 0.009 |
| PR post reading (2) | 88.00(76.00–92.00) | −0.10 | −1.25 | ||||
| 4 | Female | PR pre reading | 88.00(85.00–92.00) | −0.44 | 0.01 | −3.16 | 0.002 |
| PR post reading (2) | 92.00(88.75–96.25) | 0.45 | 0.56 | ||||
| 5 | Male | OS pre reading | 98.00(97.50–98.50) | 0.24 | 0.52 | −3.30 | 0.001 |
| OS post reading (2) | 99.00(98.50–99.00) | −0.78 | 0.28 | ||||
| 6 | Female | OS pre reading | 98.00(98.00–99.00) | −0.49 | 0.74 | −2.35 | 0.018 |
| OS post reading (2) | 99.00(98.00–99.00) | 0.38 | −0.90 | ||||
| 7 | Male | BP pre reading SBP | 122.00(116.00–129.00) | −0.54 | −0.65 | −2.22 | 0.026 |
| BP Post reading (2) SBP | 127.00(121.00–130.50) | −0.39 | 1.34 | ||||
| 8 | Female | BP pre reading SBP | 114.50(110.00–118.75) | 0.23 | −1.05 | −2.35 | 0.019 |
| BP Post reading (2) SBP | 118.50(111.50–121.25) | 0.09 | −1.00 | ||||
| 9 | Male | BP pre reading DBP | 79.00(75.00–82.50) | 0.55 | −0.20 | −0.80 | 0.422 |
| BP post reading (2) DBP | 78.00(74.50–86.50) | 0.53 | −0.57 | ||||
| 10 | Female | BP pre reading DBP | 74.00(69.50–78.75) | −0.10 | −0.56 | −1.63 | 0.102 |
| BP post reading (2) DBP | 77.00(73.50–80.25) | −0.44 | 1.18 |
*WILCOXON SIGNED RANK TEST, P < 0.05 as significant, ABBERVATION: CI- Confidence Interval, IQR: Interquartile Range, RR: Respiratory Rate, PR: Pulse Rate, OS: Oxygen Saturation, BP: blood pressure, SBP: systolic blood pressure, DBP: diastolic blood pressure.
4. Discussion
In the present study the convenience sampling technique
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was used to recruit the physiotherapy students to evaluate correlation between their BMI and cardio-respiratory fitness. The results of the study showed higher obesity rate, weak cardio respiratory fitness anda negative relationship between BMI and Vo2max among University students. Health consequences of obesity or overweight remain challenging to maintain. Health related physical fitness, including body composition, and cardio-respiratory fitness of otherwise healthy looking adults should be regularly monitored for necessary early interventions. Demographic characteristics of 43 participants were analysed using descriptive statistics (Table 1).4.1 Correlation between BMI and Vo2max
All subjects were divided into four groups based on BMI classification. Twenty one (48% of total participants) individuals were found to be within normal BMI range while 13(30%) were categorized as obese according to the Asian classification of BMI. Rest 4 (10%) and 5 (12%) were underweight and overweight respectively. Young adults are at a particular risk of transitioning to an overweight or obese BMI category.
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An association was established between BMI and Vo2 max within each of the four categories. Weak negative coefficients of correlation in group 3 and group 4indicatedthat as BMI values increased in the category of overweight and obese, capacity of O2 uptake was relatively low14
,15
; while positive coefficients of correlation in group 2 indicating that BMI raise within normal ranges has positive influence on O2 uptake (Table 2). A relatively higher number of individuals belonging to overweight and obese category raises concern as Asian population differs from western populations in terms of mean body mass and increased risk of developing co-morbidities at the same body weight. Hence a lower cut off for overweight and obese category compared to World Health Organization BMI classification is set.16
4.2 Gender specific relationship between BMI and VO2Max
The Spearman's correlation test between BMI and Vo2max values in males (ρ = −0.33) and females (ρ = −0.29), with p > 0.05 indicated statistically non significant data (Table 3). The overall Vo2 max values in present study indicated poor cardiorespiratory fitness among both male and female participants. A prior study conducted in 2015 used the Queen's College step test to assess cardio-respiratory fitness among medicos (18–24 years old), with females found to be more physically fit than their male counterparts. The majority of females (36.6%) were in the excellent and good categories, as compared to males (36.4%) in the fair group. Physical fitness was discovered to be inversely associated to BMI. Heart rate was also found to be inversely related to cardiorespiratory fitness.
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4.3 Difference between pre and post reading of variables
In both male and female participants, the variables that showed a significant difference from pre-readings to post-readings (1) (Table 4) and pre-readings to post-readings (2) (Table 5) were respiratory rate, oxygen saturation, pulse rate and systolic blood pressure. Wilcoxon sign rank test was used to examine the data and the p value less than 0.05 indicated that even post 5 min of 6MWT the vital signs were not able to return to resting levels, indicating poor cardiorespiratory fitness among individuals. Researches indicate that prolonged time (≥3 min) taken to return of heart rate to resting levels post 6MWT is an independent predictor of cardiac events among heart failure patients.
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The strength of the current study is that researchers have used digital methods to analyse the readings and the procedure is convenient and carried out in very a less amount of time. There are a few limitations in the study as the sample size is less due toCOVID-19 restrictions, so the researchers were unable to collect more samples. The study only focused on the age group of 18–25 years among physiotherapy students but it is suggested to discover more in each age group and in normal population as well.
5. Conclusion
The current investigation reported an inverse association between BMI and Vo2max among male and female individuals. Breathing and cardiac output have an impact on Vo2max, which measures total body oxygen consumption. Sedentary lifestyle lowers the lungs' ability to improve ventilation, affecting Vo2max.
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Present study revealed students at the college of physiotherapy had a high frequency of obesity and overweight and lower cardiorespiratory fitness. This makes it even more important to promote a healthy lifestyle, nutritious eating habits, and physical activity to prevent consequences from obesity.20
Funding source
None.
Declaration of competing interest
None.
Acknowledgement
we thank all the participants of the study.
References
- Prevalence of overweight and obesity based on the body mass index; A cross-sectional study in Alkharj, Saudi Arabia.Lipids Health Dis. 2018; 17: 1-8
- A study of VO2max in relation to body mass index before and after exercise in healthy young adults.J Med Sci Clin Res. 2017; (05(04)): 20290-20293
- Body-mass index and risk of obesity-related complex multimorbidity: an observational multicohort study.Lancet Diabetes Endocrinol. 2022 Apr; 10: 253-263
- Body mass index (BMI): a screening tool analysis.Cureus. 2022; 14: 1-6
- Changes in weight, physical activity, sedentary behaviour and dietary intake during the transition to higher education: a prospective study.Int J Behav Nutr Phys Activ. 2015; 15: 12-16
- Physical exercise and body-mass index in young adults: a national survey of Norwegian university students.BMC Publ Health. 2019; 19: 1354
- Does Sars-Cov-2 threaten our dreams? Effect of quarantine on sleep quality and body mass index.J Transl Med. 2020 Aug 18; 18: 318
- Relationship between maximal aerobic power with aerobic fitness as a function of signal-to-noise ratio.J Appl Physiol. 2020; 1:129: 522-532
- A study of VO 2 max in relation with body mass index (BMI) of physical education students.Res J Phys Educ Sci. 2015; 3: 9-12
- Prediction of maximal oxygen uptake by six-minute walk test and body mass index in healthy boys.J Pediatr. 2018; 200: 155-159
- Descriptive statistics and normality tests for statistical data.Ann Card Anaesth. 2019; 22: 67-72
- Ii. More than just convenient: the scientific merits of homogeneous convenience samples.Monogr Soc Res Child Dev. 2017; 82: 13-30
- Identifying adults at high-risk for change in weight and BMI in England: a longitudinal, large-scale, population-based cohort study using electronic health records.Lancet Diabetes Endocrinol. 2021; 9: 681-694
- Effect of BMI, body fat percentage and fat free mass on maximal oxygen consumption in healthy young adults.J Clin Diagn Res. 2017; 11: 17-20
- A cross-sectional study to assess the relation between physical fitness index and body mass index in medical students of index medical college, indore.J Med Sci Clin Res. 2018; 6: 778-785
- Comparison of World Health Organization and Asia-Pacific body mass index classifications in COPD patients.Int J Chronic Obstr Pulm Dis. 2017; 12: 2465-2475
- Assessment of cardiovascular fitness [VO2 max] among medical students by Queens College step test.Int J Biomed Adv Res IJBAR Int J Biomed Adv Res J. 2015; 6: 427-430
- Prolonged heart rate recovery time after 6-minute walk test is an independent risk factor for cardiac events in heart failure: a prospective cohort study.Physiotherapy. 2022; 114: 77-84
- Sedentary lifestyle: overview of updated evidence of potential health risks.Korean J Fam Med. 2020; 41: 365-373
- Healthy weight and obesity prevention: JACC health promotion series.J Am Coll Cardiol. 2018; 72: 1506-1531
Article info
Publication history
Published online: February 15, 2023
Accepted:
February 11,
2023
Received in revised form:
February 5,
2023
Received:
December 3,
2022
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© 2023 The Authors. Published by Elsevier B.V. on behalf of INDIACLEN.
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