Effects of military training on aerobic fitness, serum hormones, oxidative stress and energy balance, with special reference to overreaching
Year: 2012
Type: dissertation
Study design: Observational Study
Abstract: In Finnish compulsory military service, all conscripts have to perform the same physical training program.This may cause some conscripts to exceed their capacity to tolerate the physical load imposed and hence contribute to overreaching (OR) in a multi-stressor military environment.Therefore, this study evaluated the training load of an 8-week Finnish military basic training (BT) period during wintertime and the incidence of OR.A further aim was to investigate the associations between physical fitness, energy balance, fatness, mood state and training load during BT and during an 8-day intensive training course (TC) with easy-to-use energy supplementation.The results showed that the physical training load ( 4 MET) of BT is two hours per day with a half hour rest, such as a daily nap ( 1.0 MET), and is comparable to values found in persons performing strenuous work or daily competitive athletic training.During the first 4 weeks of BT, positive training responses as indicated by improved aerobic fitness and decreased oxidative stress, were observed.In the second half of BT, increased somatic symptoms of OR and several physiological and biochemical markers indicated that the training load was not well tolerated by all the conscripts, 33% of whom were classified as OR.OR subjects did not have increased fat mass or lower fitness before BT.Instead they showed increased oxidative stress and concentration of serum sex hormone binding globuline at rest.During BT, the OR subjects had higher physical activity than the noOR subjects.Moreover, the results confirm that markers of oxidative stress, serum cortisol, testosterone/cortisol -ratio at rest and maximal lactate/RPE -ratio could be useful tools for monitoring whether military training is too stressful.Of the three factors of energy balance, fitness and fatness, fatness limited the most high-level training while fitness protected from sick leave.TC did not have an adverse effect on physical performance.Although energy supplementation improved positive mood state, it did not prevent energy deficit or influence physical activity or performance.However, negative mood state affected energy intake already before TC.In conclusion, this thesis provides new evidence of the vulnerability of the conscripts to OR and supports the promotion of optimal energy intake to enhance performance during a strenuous military training period.
Author: Minna Tanskanen
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funder: Suomen Kulttuurirahasto
OpenAlex ID: W2214960239