Fitness and Activity Levels of German Military
Medical Personnel at the Bundeswehr Hospital Hamburg

Lorenz Scheit^a, Jan Schröder^b, Kristina Helena Wolf^a, Tony Hannes Richter^a, Christian Busch^a, Rüdiger Reer^b

^a Bundeswehr Hospital Hamburg, Department I – Internal Medicine

^b University Hamburg, Faculty of Psychology & Movement Science

Summary

Introduction: Physical fitness is a crucial demand for all military units, but the use of fitness enhancing opportunities is difficult for Medical Service soldiers. This study aimed to evaluate fitness and physical activity in different occupational groups at the Bundeswehr Hospital Hamburg.

Materials and Methods: In a cross-sectional study, anthropometric (BMI, %body fat, waist circumference) and fitness parameters (Bundeswehr basic fitness test), and physical activity (1-week-monitoring: ActiGraph® accelerometer, IPAQ questionnaire) were assessed for 129 medical staff soldiers (physicians n = 45, 60 % female; nursing n = 42, 57 % female; administration n = 2, 50 % female).

Results: Occupational groups differed significantly in %body fat (physicians < administration, p = 0.010), basic fitness (physicians > administration, p = 0.003) and physical activity (IPAQ, nursing > physicians and administration, p < 0.001). Especially, female physicians presented as being fitter than female administration staff (p = 0.031).

Conclusions: Despite a lower physical activity, medical officers demonstrated a better body composition and physical fitness than other medical occupational groups.

Keywords: personnel, fitness, readiness, Bundeswehr, military, medical personnel

Introduction

For the current and future tasks of the Bundeswehr at home and abroad, all soldiers are expected to maintain a high level of physical fitness. These fitness requirements go beyond fitness for deployment abroad and include the everyday realities of working in a hospital and providing care to patients, such as high levels of stress, long periods of standing as well as moving, mobilizing and washing patients [23]. Basic physical fitness is part of every soldier’s individual basic skills and must be demonstrated annually by passing the standardized Basic Fitness Test (BFT). At the Bundeswehr Hospital Hamburg, opportunities for on-duty exercise (at least twice a week for 90 minutes), a fitness room and occupational health management measures are provided to ensure that personnel can maintain their physical fitness beyond recreational activities in their spare time [10]. ARVIDSON et al. showed that the level of physical activity is to be related to work ability and that an active lifestyle has a high relevance for improvement of future work ability for employees [3].

Personnel shortages, irregular work schedules and commitments in everyday life, however, often mean that some occupational groups at the hospital cannot participate in sports during working hours.

For example, a study by MACCKY et al. showed a nonsignificant change in individual fitness in medical students, which suggested a decrease in physical fitness during medical training [22]. The workload of physicians and nurses – with their sometimes more dynamic work conditions and medical backgrounds – is different from that of staff and administrative personnel – who tend to have more static work profiles and less medical knowledge – and would therefore suggest a different emphasis on fitness. Poor fitness and lack of exercise not only jeopardize the ability to perform as required in the field. Combined with increasingly sedentary work and independent of other physical activities, they also increase morbidity [29] and are a risk factor for many diseases such as susceptibility to infection [13], type 2 diabetes [30], cardiovascular disease [25], and mental illness [23].

Against this background, an initial cross-sectional analysis was conducted to determine whether physicians at the Bundeswehr Hospital Hamburg differed from a cross-unit population of 55,000 members of the Bundeswehr. This analysis revealed neither significant differences in BFT scores nor a difference in the constitutional parameter body mass index (BMI) compared to the general population of the same age. Waist circumference and body fat percentage were also within the normal range according to WHO criteria [28].

To further investigate correlations between fitness, physical activity and possible restrictions on fitness for duty, it seems reasonable to also include the nursing and administrative staff of the Bundeswehr Hospital in Hamburg. This is the starting point for this study.

The aim was to determine which differences or abnormalities in fitness, constitutional fitness parameters, and activity levels are occupational group specific. Given the different workloads, differences seemed likely not only in overall physical activity but also in associated constitutional or performance/fitness parameters.

Materials and Methods

Sample description

To recruit subjects, they were directly approached and contacted via the internal information system of the Bundeswehr Hospital Hamburg. Only military personnel of the hospital were recruited as subjects. They were informed about the aim of the study, the general conditions and the voluntary nature of their participation. They agreed to participate in the study and gave their consent to the publication of the data while maintaining the confidentiality of the data. The study was approved by the ethics committee of the University of Hamburg.

In addition to baseline anthropometric and cardiovascular data, participants were asked to provide fitness data from the BFT. For inclusion in the study, participants were also required to wear an accelerometer for objective recording of activity. They were also required to keep a complete log of their physical activity for one week. Data collection for the BFT, BMI, and accelerometer occurred over a 7-day period.

A total of 129 military personnel from the Bundeswehrkrankenhaus Hamburg (57 men, 72 women) were recruited, including physicians (n = 45, 18 men, 27 women), nurses (n = 42, 18 -men, 24 women), and administrative staff (n = 42, 21 men, 21 women). All participants were hospital volunteers.

Descriptive characteristics are presented in Table 1.

Data collection tools

BMI

BMI has been used as a health risk parameter, although a high BMI can be misinterpreted in people with an athletic and muscular body type if muscle mass is not taken into account [1]. A BMI between 18.5 and < 25 kg/m² is considered normal weight. BMI values below this range are defined as underweight. People with a BMI between 25 and 30 kg/m² are considered overweight (preadipose). A BMI of 30 kg/m² or more is classified as obesity [2].

Body fat

We used the caliper method according to Parizkova to determine body fat percentage based on skin folds at ten body sites [24]. With a sample population aged between 20 and 40 years, it can be assumed that the results of this method are comparable to those of bioelectrical impedance analysis [17]. Body fat percentages between 8 % and 20 % in men and between 21 % and 33 % in women were considered normal [9].

Waist circumference

Waist circumference is considered a diagnostic criterion for metabolic syndrome and is used in addition to BMI and body fat percentage to assess nutritional state and excess body weight. It was measured with a tape measure about 2 cm above the iliac crest in a standing position after expiration. A waist circumference of <80 cm in women and of <94 cm in men was considered normal [2].

Basic Fitness Test (BFT)

The measure of physical fitness used in this study was the results of the Basic Fitness Test (BFT), which is part of an annual assessment of individual basic abilities and is scored according to a point system. BFT results were required to be available no later than two months after biometric data collection. To account for gender differences in absolute fitness, the adjusted BFT score was used as the dependent variable instead of absolute scores in the test components (1,000-meter run, pull-up test, 11x10-meter sprint test) [8][11][18][21]. An overall score of 4.49 or lower is required to pass the BFT [4].

Accelerometry

An accelerometer (ActiGraph^®, ActiLife6, FL, USA) was used to objectively measure cycles of physical activity and rest. Acceleration of the body or a body part (measured in 1-minute intervals, throughout the day, except when showering) serves as a biometric equivalent for physical activity. The ActiGraph^® was attached to a belt worn on the hip for one week. Energy consumption (kcal per unit time) can be calculated from the signals. Total metabolic rate (basal metabolic rate plus activity metabolic rate) in kcal/24 hours was used as the dependent variable. Body mass was considered in the calculation of basal metabolic rate.

International Physical Activity Questionnaire (IPAQ)

The IPAQ (October 2002 version) is a simple international questionnaire designed to assess the subjective assessment of one’s physical activity in the past 7 days [15]. The test measures any activity lasting more than 10 minutes in four domains of daily life: physical activity at work, in traffic, in the home or family, and in leisure time or sports. The metabolic equivalent in minutes per week normalized to 60 kg body weight (METmin/week/60 kg) was used as the dependent variable [15]. The METmin/week represents the ratio of work metabolic rate (amount of energy expended during physical activity) to rest metabolic rate (amount of energy expended while sitting). In this study, the questionnaire referred to the week before the Actigraph® was worn.

Statistical methods

Data were described in terms of mean (M) and standard deviation (SD). After checking the application requirements (normal distribution, variance homogeneity), main effects (gender: male versus female; occupational groups: physicians versus nurses versus administrative staff) and their interaction effects were evaluated in an analysis of variance (two-factor analysis of variance, Bonferroni-corrected post hoc test). Effect size was calculated using partial eta² (eta²p). A probability of error of p ≤ 0.05 was accepted as significant.

Results

Sample characteristics (Table 1) revealed no age differences between men and women (F=0.035; p=0.852), but differences between occupational groups (F=5.100; p=0.007). Physicians were on average 4.8 years older than administrative staff (p=0.012). Naturally, men were taller than women (∆14 cm; F=147.639; p<0.001). There were no differences in height between occupational groups (F=0.846; p=0.432). The same was true for body weight, with men being heavier than women (∆16 kg; F=58.604; p<0.001); however, there were no differences between occupational groups (F=0.300; p=0.741). Men had slightly higher resting systolic blood pressure than women (∆7 mmHg; F=19.494; p<0.001), but again there were no differences between occupational groups (F=1.694; p=0.188). Differences related to diastolic blood pressure were similar (men: ∆3 mmHg; F=8.954; p=0.003; no differences between occupational groups: F=1.893; p=0.155). There were no differences between genders (F=0.063; p=0.802) or between occupational groups (F=0.092; p=0.913) in resting heart rate (Ø 71 bpm).

Table 1: Sample characteristics (mean and standard deviation)

Abbreviations: BP = blood pressure, sys = systolic, dias = diastolic, RHR = resting heart rate

Anthropometric, activity and fitness parameters

Differences between occupational groups in terms of activity or fitness parameters were differentiated by gender and are presented in Table 2.

Anthropometric-constitutional parameters showed no significant difference between occupational groups in terms of BMI (kg/m²) (F=1.144; p=0.322), but the average BMI of men was 1.3kg/m² higher than that of women (F=4.051; p=0.046), with no interaction between factors (F=0.105; p=0.900).

 

Table 2: Fitness, physical activity, anthropometric characteristics of the occupational groups and main and interaction effects determined by analysis of variance

Abbreviations: M = mean, SD = standard deviation, m= male, f = female

^#women ≠ men (p < 0.05),*physicians < administrative personnel (p≤.01), ⁺nurses > physicians, administrative personnel (p < 0.001)

#women ≠ men (p<.05), *physicians < administrative personnel (p ≤ 0.01), +nurses > physicians, administrative personnel (p < 0.001)

Females had a statistically significantly higher body fat percentage than males, although the difference did not appear to be significant (∆1.9%; F=7.457; p=0.007). There were differences between occupational groups in terms of body fat percentage (F=5.181; p=0.007), with physicians having an average of 2.8% less body fat than administrative staff personnel (p=0.010). However, there was no significant interaction between gender and occupational group factors (F=1.126; p=0.328), indicating that physicians had lower body fat percentage than administrative staff regardless of gender.

The average waist circumference (in cm) of male subjects was naturally 10 cm larger on average than that of female subjects (F=38.935; p<0.001), but there were no differences between occupational groups (F=0.214; p=0.808) or interactions (F=0.158; p=0.854).

The gender adjusted BFT score showed no overall gender differences (F=1.81; p=0.260), but there were differences between occupational groups (F=5.477; p=0.005), with physicians scoring significantly higher than administrative staff on average (p=0.003), explaining the significant interaction between factors (occupational group x gender) (F=3.589; p=0.031). Figure 1 shows that in particular female administrative staff had a worse fitness score than female physicians.

Although there were gender differences (F = 68.130; p < 0.001) in calorie expenditure (kcal/24h) as calculated on the basis of accelerometry, with women expending less energy due to their naturally lower body mass (∆577 kcal/24h), there were no differences between the occupational groups (F = 0.265; p = 0.768), and no interaction between the factors was observed (F = 0.447; p = 0.640) as shown in Figure 2.

No differences were found between men and women (F = 0.002; p = 0.966) regarding physical activity recorded over one week with the IPAQ questionnaire (METmin/week/60 kgBW), but there were differences between the occupational groups (F = 23.371; p < 0.001). Nurses were significantly more active (p < 0.001) than physicians (∆ 7679 METmin/week/60 kgBW; p < 0.001) and administrative staff (∆ 5988 METmin/week/60 kgBW; p < 0.001). There was no interaction of the factors (F = 0.322; p = 0.726), which means that the differences between occupational groups were not related to­ ­gender.

Figure 1: BFT grades of the individual occupational groups and standard deviations

Figure 2: ActiGraph total activity levels in kcal/24h of the individual occupational groups and standard deviations

Figure 3. Activity recorded with the IPAQ-questionnaire

Discussion

The purpose of this study was to determine the specific differences between occupational groups in physical fitness and activity during a typical work week.

Although the samples were small, an even gender and occupational distribution was achieved among the study populations. The subgroups did not differ in personal characteristics; only physicians were on average 4.8 years older than administrative staff, reflecting their long academic and clinical training periods.

For anthropometric fitness parameters, the only differences between men and women in BMI, waist circumference, and body fat percentage were naturally due to gender. Only body fat percentage showed a significant difference between occupational groups, with physicians having an average of 2.8 % less body fat than administrative staff.

Physical fitness, as measured by the BFT, was better among physicians than among administrative staff, which may be attributed to female physicians scoring better than female staff members. The poorer performance of female staff members in the pull-up test, pendulum sprint, and 1,000-meter run compared with female physicians could plausibly be explained by differences in body fat percentage, although motivational aspects may have played a role in addition to possibly poorer overall fitness. Systematic differences between men and women were due to gender differences in total body mass and muscle mass.

Although physicians and nurses work more hours per week than administrative staff and therefore presumably have less time for leisure activities, which may have a negative impact on physical activity (both leisure and on duty), this did not translate into poorer physical fitness. Overall, we found good BFT values and comparable activity calorie consumption across all occupational groups at the Bundes Hospital Hamburg.

Assuming that BFT reflects baseline physical fitness, these results suggest that soldiers at the hospital are taking sufficient measures to maintain their physical fitness and thus their mission readiness, regardless of their workload. Despite higher workloads, shift and weekend work, and fewer opportunities to exercise while on duty, in particular female physicians achieved better BFT scores than female administrative personnel. We can only speculate that perhaps the knowledge that as physicians they are more likely to be deployed overseas prompts them to take the initiative to work on their fitness outside of work. SARIDI et al. described in their study that lack of free time was cited as a reason for lack of physical activity by 58 % in a study group of 106 health professionals [27].

Reflecting our own preliminary research, these results suggest that military medical personnel in all occupational groups have baseline fitness levels comparable to members of other units [28].

Physical activity during a typical work week was determined using accelerometry and self-assessment [7][12][14]. Accelerometry measurements revealed no differences in physical activity between occupational groups. However, the IPAQ recall questionnaire for a single previous work week showed a gender-independent difference, with nurses recording more physical activity. This discrepancy may be due to methodological reasons: The results of the IPAQ recall questionnaire may be biased because subjects overestimate their own activity levels. Validity problems with moderate to intense activities are well known [14][19]. International studies on the IPAQ report overestimates of up to 40 % compared to objective accelerometric measurements, especially for intense and moderate activity [5][6][7][12][20][26]. However, it can be assumed that the daily work routine in nursing includes heavy physical work, whereas the work of administrative staff is predominantly sedentary and the work of physicians, although constantly stressful, is less physically demanding. These findings can be confirmed by the study of So YEON JUN, who describes significantly lower physical activity among physicians in a hospital compared to nurses on the support staff [16].

Limitations

Although the voluntary nature of participation in the study was essential, it is a limitation of the study results. Because of this bias, it is possible that primarily healthy, athletic military personnel volunteered to participate. Participation also involved some inconvenience due to always wearing an accelerometer and recording daily activities, which may also have introduced selection bias.

Conclusions

Our comparative analysis of fitness and activity parameters of medical personnel at the Bundeswehr Hospital Hamburg revealed no relevant differences between occupational groups. The gender-adjusted basic fitness test results were consistently positive. Against the background of our own preliminary investigations, there are no differences to other units regarding physical fitness. Independent of work profile-specific aspects, the fitness for duty and deployment of all occupational groups is not subject to any objectifiable practice-relevant limitations. In the context of our study, it can be stated that physicians achieve a significantly better BFT value than administrative staff.

Methodological limitations that resulted in small sample sizes limit the generalizability of our findings. Larger studies are needed in which additional parameters such as heart rate variability can be used to objectify autonomic stress parameters.

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Acknowledgement: Captain (MC) Jana Kellner, Bundes­wehr Hopital Hamburg, contributed to the successful completion of this study by providing a variety of support to the study group.

Manuscript data

Submitted: October 4, 2021

Accepted after Revision: February 21, 2022

Citation

Scheit L, Schröder J, Wolf KH, Richter TH, Busch C, Reer R: Fitness and Activity Levels of German Military Medical Personnel at the Bundeswehr Hospital Hamburg. WMM 2022; 66(4): e3.

DOI: https://doi.org/10.48701/opus4-7

For the authors

Lieutenant Colonel Dr. Lorenz Scheit, M.Sc.

Bundeswehr Hospital Hamburg

Department I – Internal Medicine

Lesser Str. 180, D-22049 Hamburg

E-Mail: lorenzscheit@bundeswehr.org">lorenzscheit@bundeswehr.org