ECSS Paris 2023: CP-PN01
INTRODUCTION: Sleep disturbances are a potential negative consequence of problematic low energy availability [1]. For instance, four weeks of energy restriction impacted the sleep patterns of non-athletes [2]. Additionally, athletes reported, via interviews, that their subjective perception was that weight reduction negatively affected their sleep [3]. The aim of this study was to investigate the association of perceived sleep and primary indicators of Relative Energy Deficiency in Sport (REDs). METHODS: National and international level female athletes (n=128; 23.3±4.8 years) representing various sports participated in the study during their preparatory season. Athletes’ sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI). Seven components of sleep (quality, latency, duration, efficiency, disturbance, sleep medication use, and daytime dysfunction) were calculated from the PSQI. REDs indicators included primary and secondary amenorrhea assessed via LEAF-Q (low energy availability in females questionnaire), low serum free triiodothyronine concentration, history of bone stress injury, low bone mineral density (Z-score <-1) at the lumbar spine analysed by Dual-energy X-ray absorptiometry, and an elevated score for the EDE-Qs (eating disorder examination questionnaire short). Participants were divided into groups based on the use of hormonal contraception: naturally menstruating (NM, n=80) and hormonal contraceptive users (HC, n=48), and further based on the primary indicators of REDs: no-risk (0 indicator), risk (1 or more indicators). The differences in PSQI points between groups were analysed with Mann-Whitney U Test and the differences of prevalence with Chi-Square Tests (SPSS 28.0.0). RESULTS: REDs indicators were observed in 50% of NM and 54% of HC, while poor sleep (5 or more points in PSQI) was observed in 45% of NM and 40% of HC. There were no differences between no-risk and risk groups in total PSQI score or the PSQI components (NM: p=0.104-0.897; HC: p=0.367-0.791), but medication use was higher in NM-risk (p=0.023). Medication use was more prevalent in NM-risk (23%) than in NM no-risk (5%; p=0.026). Additionally, there was a trend for higher medication use (p=0.073) and prevalence of medication use (p=0.081; 21% vs. 4%) in HC-risk compared to HC-no-risk. CONCLUSION: The primary indicators of REDs were not linked to perceived sleep quality. However, female athletes with more indicators of REDs were more likely to use sleep medication. The relationship between energy availability and sleep should be further explored. 1. Mountjoy M, et al. 2023 International Olympic Committees (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023; 57(17): 1073-1097. 2. Karklin A, et al. Restricted energy intake affects nocturnal body temperature and sleep patterns. Am J Clin Nutr 1994; 59: 346–9. 3. Gillbanks L, et al. Lightweight rowers’ perspectives of living with relative energy deficiency in sport (RED- S). PLoS One 2022;17:e0265268.
Read CV Essi AhokasECSS Paris 2023: CP-PN01
INTRODUCTION: Bed rest is a common occurrence in clinical settings, including hospitals and extended care facilities. The resulting inactivity leads to muscle mass loss, reduced strength, and diminished functional capacity, which can increase mortality risk, particularly in older adults. Muscle loss in this population is strongly linked to a higher risk of falls. While physical activity is known to mitigate age-related declines in muscle mass and function in older adults, its effectiveness in counteracting the detrimental effects of bed rest on skeletal muscle mass and fiber composition in older adults remains unclear. This study examined the effects of 14 days of six-degree head-down tilt bed rest (HDBR) on muscle volume, as measured by MRI, and muscle fiber composition, assessed through biopsy samples in older adults. Additionally, it evaluated whether an in-bed exercise countermeasure could mitigate the detrimental impact of bed rest on muscle mass. METHODS: Twenty-two participants (aged 55–65 years) were randomized into two groups for a two-week HDBR: a control group (♂: 6, ♀: 5) and an exercise group (♂: 5, ♀: 6). The exercise group performed one hour of combined resistance and aerobic exercise daily while remaining in bed. Needle muscle biopsies from the vastus lateralis and calf muscle and fat volumes by MRI were conducted prior to, and after HDBR. RESULTS: At baseline, no significant differences were observed between groups. Following 14 days of bed rest, both groups experienced a reduction in total calf muscle volume (control: 28.4 ± 2.0 cm³ to 25.1 ± 2.0 cm³; exercise: 29.3 ± 2.2 cm³ to 26.7 ± 2.2 cm³). However, a significant group effect was observed in calf fat volumes, with a decrease only in the exercise group (18.1 ± 2.0 cm³ to 16.9 ± 1.9 cm³, p = 0.001), while no significant change was observed in the control group (16.2 ± 1.8 cm³ to 16.4 ± 1.7 cm³). Our preliminary findings suggest that neither bed rest alone nor bed rest with exercise significantly alters muscle fiber composition. CONCLUSION: HDBR resulted in a significant reduction in calf muscle volume in both the control and exercise groups, highlighting the rapid muscle loss associated with inactivity in older adults. However, a reduction in calf fat volume was observed only in the exercise group, suggesting potential metabolic benefits of in-bed exercise during prolonged inactivity. Further analysis will offer deeper insights into muscle fiber changes following HDBR.
Read CV Guy Hajj-BoutrosECSS Paris 2023: CP-PN01
INTRODUCTION: Cooling interventions after exercise have been used to enhance skeletal muscle mitochondrial adaptations to endurance exercise (1). Recently, we found that intermittent cooling of skeletal muscle for 1 hour modulates intramyocyte [hydrogen peroxide], which plays an important role in intramuscular signaling. This cooling pattern increases gene expression of Nrf2, a transcription factor that responds to altered [hydrogen peroxide]. Increased Nrf2 expression prior to endurance exercise enhances exercise-induced mitochondrial adaptations (2). Therefore, this investigation was designed to test the hypothesis that local cooling of skeletal muscle prior to running exercise would enhance mitochondrial adaptations in mouse skeletal muscles. METHODS: Acute experiment: Male C57Bl/6J mice (9 and 10 weeks old) were divided into sedentary (n=7) and exercise (n=7) groups. Both groups were subjected to cooling stimulation (muscle temperature: 35~13~35°C x 6 sets, total 60 min) on the left leg. The sub-groups were Room temperature + sedentary (RT + Sed), ICE + sedentary (ICE + Sed), Room temperature + exercise (RT + Ex), and ICE + exercise (ICE + Ex). The exercise group performed a 60-minute treadmill running (15 m/min, slope 10 degree incline) immediately after the temperature intervention whereas Sed animals rested. Three hours after the the exercise or rest, tibialis anterior (TA) muscles of all groups were excised, and mRNA levels of PGC1α, Ucp3, and pdk4 were measured. Training experiment: In 14 mice, the same cooling and exercise protocol as in the acute model was performed 4 times / week for 4 weeks, and 24 hours after the last training bout, TA and EDL muscles were harvested. Mitochondrial enzyme activity, mitochondrial and antioxidant-related proteins were measured. Statistical analyses using a paired two-way ANOVA, and multiple comparison tests were performed for interaction effects. A statistical level of p<0.05 was accepted. RESULTS: Acute Responses: ICE + Ex showed significantly higher levels of PGC1α mRNA than RT + Ex (+14%, p=0.012). Ucp3 and Pdk4 increased with exercise (p<0.001), but decreased with cooling stimulation (p<0.05). Training Responses: CS activity increased additively (+18%) with the combination of training and cooling as did β-HAD activity compared with training alone (+24%, p=0.017). There were no differences in the levels of mitochondrial-related proteins OXPHOS, PGC1α, or antioxidant enzymes Sod1,2 among groups. CONCLUSION: Local cooling stimulation of skeletal muscle prior to acute running exercise promoted an increase in PGC1α mRNA levels. Running training under pre-cooling conditions increased the activity of the mitochondrial enzymes CS and β-HAD compared to training under normal conditions. This study demonstrates that pre-conditioning with local cooling has a synergistic effect on the mitochondrial adaptations induced by running exercise.
Read CV Ryotaro KanoECSS Paris 2023: CP-PN01