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Lundell RV, Saarelainen R, Parkkola KI, Wuorimaa TK. A 15-Year Longitudinal Study of Body Composition in Finnish Military Divers. Mil Med 2023:usad401. [PMID: 37878799 DOI: 10.1093/milmed/usad401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/05/2023] [Accepted: 10/05/2023] [Indexed: 10/27/2023] Open
Abstract
INTRODUCTION Finnish military divers perform a great variety of tasks all year round, all of which require good physical health and fitness. Poor physical fitness can hinder the ability to cope with different situations. A high body fat percentage has been suggested to increase the risk of decompression sickness, whereas low muscle mass has been associated with an increased risk of musculoskeletal disorders and trauma. However, a low-fat composition may render divers vulnerable to cold and hypothermia during a dive in cold Arctic conditions. The aim of this study was to evaluate possible changes in body composition of Finnish military divers during a 15-year follow-up period (2007-2021). MATERIALS AND METHODS We used body composition measures from military divers' fit-to-dive evaluations from the Finnish Defence Forces' Diving Medical Centre. Measurements were taken with two bioimpedance devices that function based on the electrical conductivity properties of the human body. The data from both devices were compared with Bland-Altman plots to show that the devices produced congruent data and the results from both devices could be included in the study. Possible changes in body composition were evaluated with a linear mixed model with random intercepts and slopes for each variable. RESULTS Results from the two bioimpedance devices showed no significant differences. This allowed us to combine the results in the same data analysis. There were no apparent differences in the age of the divers between the years during the follow-up. The majority of the divers were between 25 and 30 years of age. Age correlated significantly with most measures, the clinically most significant being a higher fat percentage in older divers. However, all measures were within target values defined by the Diving Medical Centre. The divers were able to retain sufficient muscle mass in all age groups. DISCUSSION AND CONCLUSIONS According to this study, Finnish military divers have managed to maintain a surprisingly good muscle mass in all age groups despite body composition changes due to aging in older subjects. A slight increase in fat mass can be observed with increasing age; nevertheless, the values have remained within fit-to-dive target levels. The current training routines of Finnish military divers are adequate for maintaining solid physical fitness and body composition over the course of the diving career.
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Affiliation(s)
- Richard V Lundell
- Field Medicine Services Unit, Centre for Military Medicine, Finnish Defence Forces, Riihimäki 11311, Finland
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland, and Helsinki University, Helsinki 00860, Finland
- Department of Pathology, Helsinki University, Helsinki 00014, Finland
| | - Ray Saarelainen
- Diving Medical Centre, Centre for Military Medicine, Finnish Defence Forces, Kirkkonummi 02470, Finland
| | - Kai I Parkkola
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland, and Helsinki University, Helsinki 00860, Finland
- Department of Pathology, Helsinki University, Helsinki 00014, Finland
- Faculty of Medicine and Health Technology, Tampere University, Tampere 33100, Finland
| | - Tomi K Wuorimaa
- Diving Medical Centre, Centre for Military Medicine, Finnish Defence Forces, Kirkkonummi 02470, Finland
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Myllylä M, Parkkola KI, Ojanen T, Heinonen OJ, Ruohola JP, Vahlberg T, Kyröläinen H. Effects of 12-Month Training Intervention on Physical Fitness, Body Composition, and Health Markers in Finnish Navy Soldiers. Healthcare (Basel) 2023; 11:2698. [PMID: 37830735 PMCID: PMC10572769 DOI: 10.3390/healthcare11192698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/02/2023] [Accepted: 10/07/2023] [Indexed: 10/14/2023] Open
Abstract
BACKGROUND Most Western adults do not meet the recommendations for sufficient activity, and obesity is a global problem. Similar trends are also seen among Western military personnel. Many successful physical training interventions have been carried out in military environments, but the interventions have been quite short term, and the training has been supervised. Therefore, the aim of this study was to investigate the effects of a 12-month voluntary motivational training intervention among the Finnish Defence Forces' (FDF) Navy soldiers. METHODS In total, 77 FDF Navy soldiers, serving in missile patrol boats, took part in the study. The intervention group (IG) contained 45 participants and the control group (CG) contained 32 participants. The IG was divided into four teams that carried out the intervention, while the CG took part in only the measurements. RESULTS Most of the participants (65%) in the IG reported that they had increased their exercise volume during the intervention, but no major beneficial impacts on the physical fitness, body composition, or health markers were observed. Nevertheless, there was a clear diversity visible between the subgroups in the IG. The team that reported the most exercise had the best motivation and the most motivated team coach and also had the most improved physical fitness and body composition results. CONCLUSIONS The present study points out that in military environments, long-term voluntary training interventions may not be as successful as short-term supervised interventions. The results also suggest that in voluntary training interventions among military personnel, the participants' motivation to exercise is a key factor when improving physical fitness.
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Affiliation(s)
- Mikko Myllylä
- Centre for Military Medicine, The Finnish Defence Forces, 20241 Turku, Finland
- Doctoral Programme in Clinical Research, University of Turku, 20014 Turku, Finland
| | - Kai I. Parkkola
- Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
- Department of Leadership and Military Pedagogy, National Defence University, 00861 Helsinki, Finland
| | - Tommi Ojanen
- Human Performance Division, Finnish Defence Research Agency, The Finnish Defence Forces, 04310 Tuusula, Finland
| | - Olli J. Heinonen
- Paavo Nurmi Centre & Unit for Health and Physical Activity, University of Turku, 20520 Turku, Finland
| | - Juha-Petri Ruohola
- Defence Command Finland, The Finnish Defence Forces, 00131 Helsinki, Finland
| | - Tero Vahlberg
- Department of Biostatistics, University of Turku, 20014 Turku, Finland
| | - Heikki Kyröläinen
- Department of Leadership and Military Pedagogy, National Defence University, 00861 Helsinki, Finland
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, 40014 Jyväskylä, Finland
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Myllylä M, Kyröläinen H, Ojanen T, Ruohola JP, Heinonen OJ, Simola P, Vahlberg T, Parkkola KI. The Effects of Individual Characteristics of the Naval Personnel on Sleepiness and Stress during Two Different Watchkeeping Schedules. Int J Environ Res Public Health 2022; 19:13451. [PMID: 36294028 PMCID: PMC9603121 DOI: 10.3390/ijerph192013451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Naval service can have a significant impact on the wellbeing of seafarers, and the operation of warships is highly dependent on the personnel on board. Nevertheless, there is a lack of knowledge concerning the impact of seafarers' individual characteristics on their wellbeing in a naval environment. Therefore, the aim of this study was to investigate individual characteristics of the naval personnel that may be associated with the amount of sleepiness, fatigue and stress responses experienced during shift work and irregular working hours in a naval environment. METHODS The study took place on a Finnish Defence Forces' Navy missile patrol boat on which 18 crewmembers served as study participants. The measurement periods lasted two separate weeks (seven days and six nights) during shift work with two different watchkeeping systems (4:4, 4:4/6:6). The onboard measurements consisted of the Karolinska Sleepiness Scale, salivary stress hormones, cognitive tests (Sustained Attention to Response Task and N-back Task) and heart rate variability. RESULTS Participants of older ages or with a longer history in naval service were associated with a greater amount of sleepiness, fatigue and stress responses on board. On the contrary, increased physical activity and a higher level of physical fitness, especially standing long jump, were associated with a lower amount of sleepiness, fatigue and fewer stress responses. In addition, an athletic body composition together with a healthy lifestyle may be beneficial, considering the stress responses on board. CONCLUSION The present results are well in line with the previous literature regarding shift work and irregular working hours. The results highlight the importance of regular physical activity and good physical fitness during service in the naval environment.
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Affiliation(s)
- Mikko Myllylä
- Centre for Military Medicine, The Finnish Defence Forces, 20241 Turku, Finland
- Doctoral Programme in Clinical Research, University of Turku, 20014 Turku, Finland
| | - Heikki Kyröläinen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, 40014 Jyväskylä, Finland
- Department of Leadership and Military Pedagogy, National Defence University, 00861 Helsinki, Finland
| | - Tommi Ojanen
- Human Performance Division, Finnish Defence Research Agency, The Finnish Defence Forces, 04310 Tuusula, Finland
| | - Juha-Petri Ruohola
- The Navy Command Finland, The Finnish Defence Forces, 20811 Turku, Finland
| | - Olli J. Heinonen
- Paavo Nurmi Centre & Unit of Health and Physical Activity, University of Turku, 20520 Turku, Finland
| | - Petteri Simola
- Human Performance Division, Finnish Defence Research Agency, The Finnish Defence Forces, 04310 Tuusula, Finland
| | - Tero Vahlberg
- Department of Biostatistics, University of Turku, 20014 Turku, Finland
| | - Kai I. Parkkola
- Department of Leadership and Military Pedagogy, National Defence University, 00861 Helsinki, Finland
- Faculty of Medicine and Health Technology, Tampere University, 33100 Tampere, Finland
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Myllylä M, Kyröläinen H, Ojanen T, Ruohola JP, Heinonen OJ, Vahlberg T, Parkkola KI. Effects of operational assessment of the 4:4 and 4:4/6:6 watch systems on sleepiness, fatigue, and stress responses during patrolling on a navy missile patrol boat. Chronobiol Int 2022; 39:1233-1241. [DOI: 10.1080/07420528.2022.2090374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Mikko Myllylä
- Centre for Military Medicine, The Finnish Defence Forces, Turku, Finland
- Doctoral Programme in Clinical Research, University of Turku, Turku, Finland
| | - Heikki Kyröläinen
- Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
| | - Tommi Ojanen
- Human Performance Division, Finnish Defence Research Agency, The Finnish Defence Forces, Tuusula, Finland
| | | | - Olli J. Heinonen
- Paavo Nurmi Centre & Unit of Health and Physical Activity, University of Turku, Turku, Finland
| | - Tero Vahlberg
- Department of Biostatistics, University of Turku, Turku, Finland
| | - Kai I. Parkkola
- Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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Lundell RV, Räisänen-Sokolowski AK, Wuorimaa TK, Ojanen T, Parkkola KI. Diving in the Arctic: Cold Water Immersion's Effects on Heart Rate Variability in Navy Divers. Front Physiol 2020; 10:1600. [PMID: 32082177 PMCID: PMC7005786 DOI: 10.3389/fphys.2019.01600] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 12/20/2019] [Indexed: 11/13/2022] Open
Abstract
Introduction Diving close to the Arctic circle means diving in cold water regardless of the time of year. The human body reacts to cold through autonomous nervous system (ANS)-mediated thermoregulatory mechanisms. Diving also induces ANS responses as a result of the diving reflex. Materials and Methods In order to study ANS responses during diving in Arctic water temperatures, we retrospectively analyzed repeated 5-min heart rate variability (HRV) measures and the mean body temperature from dives at regular intervals using naval diving equipment measurement tests in 0°C water. Three divers performed seven dives without physical activity (81–91 min), and two divers performed four dives with physical activity after 10 min of diving (0–10 min HRV recordings were included in the study). Results Our study showed a significant increase in parasympathetic activity (PNS) at the beginning of the dives, after which PNS activity decreased significantly (measure 5–10 min). Subsequent measurements (15–20 min and onward) showed a significant increase in PNS activity over time. Conclusion Our results suggest that the first PNS responses of the human diving reflex decrease quickly. Adverse effects of PNS activity should be considered on long and cold dives. To avoid concurrent sympathetic (SNS) and PNS activity at the beginning of dives, which in turn may increase the risk of arrhythmia in cold water, we suggest a short adaptation phase before physical activity. Moreover, we suggest it is prudent to give special attention to cardiovascular risk factors during pre-dive examinations for cold water divers.
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Affiliation(s)
- Richard V Lundell
- Diving Medical Centre, Centre for Military Medicine, The Finnish Defence Forces, Helsinki, Finland.,Doctoral Programme in Clinical Research, University of Helsinki, Helsinki, Finland
| | - Anne K Räisänen-Sokolowski
- Department of Pathology, HUSLAB, Helsinki University Hospital, University of Helsinki, Helsinki, Finland.,Centre for Military Medicine, The Finnish Defence Forces, Kirkkonummi, Finland
| | - Tomi K Wuorimaa
- Diving Medical Centre, Centre for Military Medicine, The Finnish Defence Forces, Kirkkonummi, Finland
| | - Tommi Ojanen
- Human Performance Division, Finnish Defence Research Agency, The Finnish Defence Forces, Tuusula, Finland
| | - Kai I Parkkola
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,National Defence University, Helsinki, Finland
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Varis N, Parkkola KI, Leino TK. Hypoxia Hangover and Flight Performance After Normobaric Hypoxia Exposure in a Hawk Simulator. Aerosp Med Hum Perform 2019; 90:720-724. [PMID: 31331422 DOI: 10.3357/amhp.5289.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION: The incidence of hypoxia-like symptoms in military aviators is on the rise. Cases can be related to On-Board Oxygen Generating System (OBOGS) malfunction, air contamination, loss of cabin pressurization, hyperventilation, or a combination of these issues simultaneously. Normobaric hypoxia training in tactical fighter simulations has been conducted in the Finnish Air Force since 2008. This training helps aviators to recognize their individual hypoxia symptoms and refreshes hypoxia emergency procedures in a realistic cockpit.METHODS: A flight mission included three set-ups and a return to base (RTB) after the third set-up. In a tactical Hawk simulator, different concentrations of oxygen were used (8%, 7%, and 6% oxygen in nitrogen) to create normobaric hypoxia exposures. During the RTB, the flight instructor evaluated the subjects' flight performance (N = 16) in order to estimate cognitive functions after hypoxia. A control flight was evaluated before or after the flight with normobaric hypoxia exposure.RESULTS: Instrumental flight rule performance during RTB decreased significantly from 4.81 to 3.63 after normobaric hypoxia and emergency procedures. Some pilots reported fatigue, headache, memory problems, and cognitive impairment as adverse effects up to 12 h after normobaric hypoxia training.DISCUSSION: Hypoxia has a significant effect on flight performance during RTB, even 10 min after hypoxia emergency procedures. Since 100% oxygen was used as emergency oxygen, as in a real aircraft, the oxygen paradox may decrease flight performance. Hypoxia training in tactical fighter simulations provides an opportunity for pilots to also understand the effects of the "hypoxia hangover" on their flight performance.Varis N, Parkkola KI, Leino TK. Hypoxia hangover and flight performance after normobaric hypoxia exposure in a Hawk simulator. Aerosp Med Hum Perform. 2019; 90(8):720-724.
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